Use XmlStringBuilder in most toXML() bodies

Also change StringUtils.escapeForXML() and Packet.toXML() to return
CharSequence instead of String. XmlStringBuilder now has 'optX' methods.

Remove XmlUtils in favor of XmlStringBuilder

bosh/src/main/java/org/jivesoftware/smack/BOSHConnection.java

@@ -338,7 +338,7 @@ public class BOSHConnection extends XMPPConnection {
     void sendPacketInternal(Packet packet) {
         if (!done) {
             try {
-                send(ComposableBody.builder().setPayloadXML(packet.toXML())
+                send(ComposableBody.builder().setPayloadXML(packet.toXML().toString())
                         .build());
             } catch (BOSHException e) {
                 LOGGER.log(Level.SEVERE, "BOSHException in sendPacketInternal", e);
@@ -391,7 +391,7 @@ public class BOSHConnection extends XMPPConnection {
         try {
             client.disconnect(ComposableBody.builder()
                     .setNamespaceDefinition("xmpp", XMPP_BOSH_NS)
-                    .setPayloadXML(unavailablePresence.toXML())
+                    .setPayloadXML(unavailablePresence.toXML().toString())
                     .build());
             // Wait 150 ms for processes to clean-up, then shutdown.
             Thread.sleep(150);

core/src/main/java/org/jivesoftware/smack/DirectoryRosterStore.java

@@ -291,9 +291,9 @@ public class DirectoryRosterStore implements RosterStore {
         XmlStringBuilder xml = new XmlStringBuilder();
         xml.openElement("item");
         xml.element("user", item.getUser());
-        xml.element("name", item.getName());
+        xml.optElement("name", item.getName());
-        xml.element("type", item.getItemType());
+        xml.optElement("type", item.getItemType());
-        xml.element("status", item.getItemStatus());
+        xml.optElement("status", item.getItemStatus());
         for (String groupName : item.getGroupNames()) {
             xml.openElement("group");
             xml.element("groupName", groupName);

core/src/main/java/org/jivesoftware/smack/debugger/LiteDebugger.java

@@ -241,8 +241,8 @@ public class LiteDebugger implements SmackDebugger {
         // data as Smack sees it and not as it's coming in as raw XML.
         listener = new PacketListener() {
             public void processPacket(Packet packet) {
-                interpretedText1.append(packet.toXML());
+                interpretedText1.append(packet.toXML().toString());
-                interpretedText2.append(packet.toXML());
+                interpretedText2.append(packet.toXML().toString());
                 interpretedText1.append(NEWLINE);
                 interpretedText2.append(NEWLINE);
             }

core/src/main/java/org/jivesoftware/smack/packet/Bind.java

@@ -17,6 +17,8 @@
 
 package org.jivesoftware.smack.packet;
 
+import org.jivesoftware.smack.util.XmlStringBuilder;
+
 /**
  * IQ packet used by Smack to bind a resource and to obtain the jid assigned by the server.
  * There are two ways to bind a resource. One is simply sending an empty Bind packet where the
@@ -53,16 +55,16 @@ public class Bind extends IQ {
         this.jid = jid;
     }
 
-    public String getChildElementXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public CharSequence getChildElementXML() {
-        buf.append("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
+        XmlStringBuilder xml = new XmlStringBuilder();
-        if (resource != null) {
+        xml.halfOpenElement("bind");
-            buf.append("<resource>").append(resource).append("</resource>");
+        xml.xmlnsAttribute("urn:ietf:params:xml:ns:xmpp-bind");
-        }
+        xml.rightAngelBracket();
-        if (jid != null) {
+        xml.optElement("resource", resource);
-            buf.append("<jid>").append(jid).append("</jid>");
+        xml.optElement("jid", jid);
-        }
+        xml.closeElement("bind");
-        buf.append("</bind>");
+
-        return buf.toString();
+        return xml;
     }
 }

core/src/main/java/org/jivesoftware/smack/packet/DefaultPacketExtension.java

@@ -19,6 +19,8 @@ package org.jivesoftware.smack.packet;
 
 import java.util.*;
 
+import org.jivesoftware.smack.util.XmlStringBuilder;
+
 /**
  * Default implementation of the PacketExtension interface. Unless a PacketExtensionProvider
  * is registered with {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager},
@@ -76,17 +78,16 @@ public class DefaultPacketExtension implements PacketExtension {
         return namespace;
     }
 
-    public String toXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public CharSequence toXML() {
-        buf.append("<").append(elementName).append(" xmlns=\"").append(namespace).append("\">");
+        XmlStringBuilder buf = new XmlStringBuilder();
+        buf.halfOpenElement(elementName).xmlnsAttribute(namespace).rightAngelBracket();
         for (String name : getNames()) {
             String value = getValue(name);
-            buf.append("<").append(name).append(">");
+            buf.element(name, value);
-            buf.append(value);
-            buf.append("</").append(name).append(">");
         }
-        buf.append("</").append(elementName).append(">");
+        buf.closeElement(elementName);
-        return buf.toString();
+        return buf;
     }
 
     /**

core/src/main/java/org/jivesoftware/smack/packet/IQ.java

@@ -17,7 +17,7 @@
 
 package org.jivesoftware.smack.packet;
 
-import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 /**
  * The base IQ (Info/Query) packet. IQ packets are used to get and set information
@@ -71,36 +71,27 @@ public abstract class IQ extends Packet {
         }
     }
 
-    public String toXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public CharSequence toXML() {
-        buf.append("<iq ");
+        XmlStringBuilder buf = new XmlStringBuilder();
-        if (getPacketID() != null) {
+        buf.halfOpenElement("iq");
-            buf.append("id=\"" + getPacketID() + "\" ");
+        addCommonAttributes(buf);
-        }
-        if (getTo() != null) {
-            buf.append("to=\"").append(StringUtils.escapeForXML(getTo())).append("\" ");
-        }
-        if (getFrom() != null) {
-            buf.append("from=\"").append(StringUtils.escapeForXML(getFrom())).append("\" ");
-        }
         if (type == null) {
-            buf.append("type=\"get\">");
+            buf.attribute("type", "get");
         }
         else {
-            buf.append("type=\"").append(getType()).append("\">");
+            buf.attribute("type", type.toString());
         }
+        buf.rightAngelBracket();
         // Add the query section if there is one.
-        String queryXML = getChildElementXML();
+        buf.optAppend(getChildElementXML());
-        if (queryXML != null) {
-            buf.append(queryXML);
-        }
         // Add the error sub-packet, if there is one.
         XMPPError error = getError();
         if (error != null) {
             buf.append(error.toXML());
         }
-        buf.append("</iq>");
+        buf.closeElement("iq");
-        return buf.toString();
+        return buf;
     }
 
     /**
@@ -111,7 +102,7 @@ public abstract class IQ extends Packet {
      *
      * @return the child element section of the IQ XML.
      */
-    public abstract String getChildElementXML();
+    public abstract CharSequence getChildElementXML();
 
     /**
      * Convenience method to create a new empty {@link Type#RESULT IQ.Type.RESULT}
@@ -170,7 +161,8 @@ public abstract class IQ extends Packet {
                     "IQ must be of type 'set' or 'get'. Original IQ: " + request.toXML());
         }
         final IQ result = new IQ() {
-            public String getChildElementXML() {
+            @Override
+            public CharSequence getChildElementXML() {
                 return request.getChildElementXML();
             }
         };

core/src/main/java/org/jivesoftware/smack/packet/Message.java

@@ -17,7 +17,7 @@
 
 package org.jivesoftware.smack.packet;
 
-import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.util.*;
 
@@ -404,59 +404,47 @@ public class Message extends Packet {
         
     }
 
-    public String toXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public XmlStringBuilder toXML() {
-        buf.append("<message");
+        XmlStringBuilder buf = new XmlStringBuilder();
-        if (getXmlns() != null) {
+        buf.halfOpenElement("message");
-            buf.append(" xmlns=\"").append(getXmlns()).append("\"");
+        buf.xmlnsAttribute(getXmlns());
-        }
+        buf.xmllangAttribute(getLanguage());
-        if (language != null) {
+        addCommonAttributes(buf);
-            buf.append(" xml:lang=\"").append(getLanguage()).append("\"");
-        }
-        if (getPacketID() != null) {
-            buf.append(" id=\"").append(getPacketID()).append("\"");
-        }
-        if (getTo() != null) {
-            buf.append(" to=\"").append(StringUtils.escapeForXML(getTo())).append("\"");
-        }
-        if (getFrom() != null) {
-            buf.append(" from=\"").append(StringUtils.escapeForXML(getFrom())).append("\"");
-        }
         if (type != Type.normal) {
-            buf.append(" type=\"").append(type).append("\"");
+            buf.attribute("type", type);
         }
-        buf.append(">");
+        buf.rightAngelBracket();
+
         // Add the subject in the default language
         Subject defaultSubject = getMessageSubject(null);
         if (defaultSubject != null) {
-            buf.append("<subject>").append(StringUtils.escapeForXML(defaultSubject.subject)).append("</subject>");
+            buf.element("subject", defaultSubject.subject);
         }
         // Add the subject in other languages
         for (Subject subject : getSubjects()) {
             // Skip the default language
             if(subject.equals(defaultSubject))
                 continue;
-            buf.append("<subject xml:lang=\"").append(subject.language).append("\">");
+            buf.halfOpenElement("subject").xmllangAttribute(subject.language).rightAngelBracket();
-            buf.append(StringUtils.escapeForXML(subject.subject));
+            buf.escape(subject.subject);
-            buf.append("</subject>");
+            buf.closeElement("subject");
         }
         // Add the body in the default language
         Body defaultBody = getMessageBody(null);
         if (defaultBody != null) {
-            buf.append("<body>").append(StringUtils.escapeForXML(defaultBody.message)).append("</body>");
+            buf.element("body", defaultBody.message);
         }
         // Add the bodies in other languages
         for (Body body : getBodies()) {
             // Skip the default language
             if(body.equals(defaultBody))
                 continue;
-            buf.append("<body xml:lang=\"").append(body.getLanguage()).append("\">");
+            buf.halfOpenElement("body").xmllangAttribute(body.getLanguage()).rightAngelBracket();
-            buf.append(StringUtils.escapeForXML(body.getMessage()));
+            buf.escape(body.getMessage());
-            buf.append("</body>");
+            buf.closeElement("body");
-        }
-        if (thread != null) {
-            buf.append("<thread>").append(thread).append("</thread>");
         }
+        buf.optElement("thread", thread);
         // Append the error subpacket if the message type is an error.
         if (type == Type.error) {
             XMPPError error = getError();
@@ -466,8 +454,8 @@ public class Message extends Packet {
         }
         // Add packet extensions, if any are defined.
         buf.append(getExtensionsXML());
-        buf.append("</message>");
+        buf.closeElement("message");
-        return buf.toString();
+        return buf;
     }
 
 

core/src/main/java/org/jivesoftware/smack/packet/Packet.java

@@ -18,6 +18,7 @@
 package org.jivesoftware.smack.packet;
 
 import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.io.ByteArrayOutputStream;
 import java.io.ObjectOutputStream;
@@ -352,7 +353,7 @@ public abstract class Packet {
      *
      * @return the XML format of the packet as a String.
      */
-    public abstract String toXML();
+    public abstract CharSequence toXML();
 
     /**
      * Returns the extension sub-packets (including properties data) as an XML
@@ -361,40 +362,47 @@ public abstract class Packet {
      * @return the extension sub-packets as XML or the Empty String if there
      * are no packet extensions.
      */
-    protected synchronized String getExtensionsXML() {
+    protected synchronized CharSequence getExtensionsXML() {
-        StringBuilder buf = new StringBuilder();
+        XmlStringBuilder xml = new XmlStringBuilder();
         // Add in all standard extension sub-packets.
         for (PacketExtension extension : getExtensions()) {
-            buf.append(extension.toXML());
+            xml.append(extension.toXML());
         }
         // Add in packet properties.
         if (properties != null && !properties.isEmpty()) {
-            buf.append("<properties xmlns=\"http://www.jivesoftware.com/xmlns/xmpp/properties\">");
+            xml.halfOpenElement("properties").xmlnsAttribute("http://www.jivesoftware.com/xmlns/xmpp/properties");
             // Loop through all properties and write them out.
             for (String name : getPropertyNames()) {
                 Object value = getProperty(name);
-                buf.append("<property>");
+                xml.openElement("property");
-                buf.append("<name>").append(StringUtils.escapeForXML(name)).append("</name>");
+                xml.element("name", name);
-                buf.append("<value type=\"");
+                xml.halfOpenElement("value");
+
+                String type;
+                String valueStr;
                 if (value instanceof Integer) {
-                    buf.append("integer\">").append(value).append("</value>");
+                    type = "integer";
+                    valueStr = Integer.toString((Integer)value);
                 }
                 else if (value instanceof Long) {
-                    buf.append("long\">").append(value).append("</value>");
+                    type = "long";
+                    valueStr = Long.toString((Long) value);
                 }
                 else if (value instanceof Float) {
-                    buf.append("float\">").append(value).append("</value>");
+                    type = "float";
+                    valueStr = Float.toString((Float) value);
                 }
                 else if (value instanceof Double) {
-                    buf.append("double\">").append(value).append("</value>");
+                    type = "double";
+                    valueStr = Double.toString((Double) value);
                 }
                 else if (value instanceof Boolean) {
-                    buf.append("boolean\">").append(value).append("</value>");
+                    type = "boolean";
+                    valueStr = Boolean.toString((Boolean) value);
                 }
                 else if (value instanceof String) {
-                    buf.append("string\">");
+                    type = "string";
-                    buf.append(StringUtils.escapeForXML((String)value));
+                    valueStr = (String) value;
-                    buf.append("</value>");
                 }
                 // Otherwise, it's a generic Serializable object. Serialized objects are in
                 // a binary format, which won't work well inside of XML. Therefore, we base-64
@@ -406,12 +414,13 @@ public abstract class Packet {
                         byteStream = new ByteArrayOutputStream();
                         out = new ObjectOutputStream(byteStream);
                         out.writeObject(value);
-                        buf.append("java-object\">");
+                        type ="java-object";
-                        String encodedVal = StringUtils.encodeBase64(byteStream.toByteArray());
+                        valueStr = StringUtils.encodeBase64(byteStream.toByteArray());
-                        buf.append(encodedVal).append("</value>");
                     }
                     catch (Exception e) {
                         LOGGER.log(Level.SEVERE, "Error encoding java object", e);
+                        type ="java-object";
+                        valueStr = "Serializing error: " + e.getMessage();
                     }
                     finally {
                         if (out != null) {
@@ -432,11 +441,15 @@ public abstract class Packet {
                         }
                     }
                 }
-                buf.append("</property>");
+                xml.attribute("type", type);
+                xml.rightAngelBracket();
+                xml.escape(valueStr);
+                xml.closeElement("value");
+                xml.closeElement("property");
             }
-            buf.append("</properties>");
+            xml.closeElement("properties");
         }
-        return buf.toString();
+        return xml;
     }
 
     public String getXmlns() {
@@ -488,6 +501,17 @@ public abstract class Packet {
 
     @Override
     public String toString() {
-        return toXML();
+        return toXML().toString();
+    }
+
+    /**
+     * Add to, from and id attributes
+     *
+     * @param xml
+     */
+    protected void addCommonAttributes(XmlStringBuilder xml) {
+        xml.optAttribute("id", getPacketID());
+        xml.optAttribute("to", getTo());
+        xml.optAttribute("from", getFrom());
     }
 }

core/src/main/java/org/jivesoftware/smack/packet/PacketExtension.java

@@ -49,5 +49,5 @@ public interface PacketExtension {
      *
      * @return the packet extension as XML.
      */
-    public String toXML();
+    public CharSequence toXML();
 }

core/src/main/java/org/jivesoftware/smack/packet/Presence.java

@@ -17,7 +17,7 @@
 
 package org.jivesoftware.smack.packet;
 
-import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 /**
  * Represents XMPP presence packets. Every presence packet has a type, which is one of
@@ -220,49 +220,35 @@ public class Presence extends Packet {
         this.language = language;
     }
 
-    public String toXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public XmlStringBuilder toXML() {
-        buf.append("<presence");
+        XmlStringBuilder buf = new XmlStringBuilder();
-        if(getXmlns() != null) {
+        buf.halfOpenElement("presence");
-            buf.append(" xmlns=\"").append(getXmlns()).append("\"");
+        buf.xmlnsAttribute(getXmlns());
-        }
+        buf.xmllangAttribute(getLanguage());
-        if (language != null) {
+        addCommonAttributes(buf);
-            buf.append(" xml:lang=\"").append(getLanguage()).append("\"");
-        }
-        if (getPacketID() != null) {
-            buf.append(" id=\"").append(getPacketID()).append("\"");
-        }
-        if (getTo() != null) {
-            buf.append(" to=\"").append(StringUtils.escapeForXML(getTo())).append("\"");
-        }
-        if (getFrom() != null) {
-            buf.append(" from=\"").append(StringUtils.escapeForXML(getFrom())).append("\"");
-        }
         if (type != Type.available) {
-            buf.append(" type=\"").append(type).append("\"");
+            buf.attribute("type", type);
-        }
-        buf.append(">");
-        if (status != null) {
-            buf.append("<status>").append(StringUtils.escapeForXML(status)).append("</status>");
         }
+        buf.rightAngelBracket();
+
+        buf.optElement("status", status);
         if (priority != Integer.MIN_VALUE) {
-            buf.append("<priority>").append(priority).append("</priority>");
+            buf.element("priority", Integer.toString(priority));
         }
         if (mode != null && mode != Mode.available) {
-            buf.append("<show>").append(mode).append("</show>");
+            buf.element("show", mode);
         }
-
+        buf.append(getExtensionsXML());
-        buf.append(this.getExtensionsXML());
 
         // Add the error sub-packet, if there is one.
         XMPPError error = getError();
         if (error != null) {
             buf.append(error.toXML());
         }
+        buf.closeElement("presence");
 
-        buf.append("</presence>");
+        return buf;
-        
-        return buf.toString();
     }
 
     public String toString() {

core/src/main/java/org/jivesoftware/smack/packet/Registration.java

@@ -19,6 +19,8 @@ package org.jivesoftware.smack.packet;
 
 import java.util.Map;
 
+import org.jivesoftware.smack.util.XmlStringBuilder;
+
 /**
  * Represents registration packets. An empty GET query will cause the server to return information
  * about it's registration support. SET queries can be used to create accounts or update
@@ -85,23 +87,22 @@ public class Registration extends IQ {
         this.attributes = attributes;
     }
 
-    public String getChildElementXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public XmlStringBuilder getChildElementXML() {
-        buf.append("<query xmlns=\"jabber:iq:register\">");
+        XmlStringBuilder xml = new XmlStringBuilder();
-        if (instructions != null) {
+        xml.halfOpenElement("query");
-            buf.append("<instructions>").append(instructions).append("</instructions>");
+        xml.xmlnsAttribute("jabber:iq:register");
-        }
+        xml.rightAngelBracket();
+        xml.optElement("instructions", instructions);
         if (attributes != null && attributes.size() > 0) {
             for (String name : attributes.keySet()) {
                 String value = attributes.get(name);
-                buf.append("<").append(name).append(">");
+                xml.element(name, value);
-                buf.append(value);
-                buf.append("</").append(name).append(">");
             }
         }
         // Add packet extensions, if any are defined.
-        buf.append(getExtensionsXML());
+        xml.append(getExtensionsXML());
-        buf.append("</query>");
+        xml.closeElement("query");
-        return buf.toString();
+        return xml;
     }
 }

core/src/main/java/org/jivesoftware/smack/packet/RosterPacket.java

@@ -18,6 +18,7 @@
 package org.jivesoftware.smack.packet;
 
 import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.util.*;
 import java.util.concurrent.CopyOnWriteArraySet;
@@ -65,22 +66,20 @@ public class RosterPacket extends IQ {
         }
     }
 
-    public String getChildElementXML() {
+    public CharSequence getChildElementXML() {
-        StringBuilder buf = new StringBuilder();
+        XmlStringBuilder buf = new XmlStringBuilder();
-        buf.append("<query xmlns=\"jabber:iq:roster\"");
+        buf.halfOpenElement("query");
-        if (rosterVersion != null) {
+        buf.xmlnsAttribute("jabber:iq:roster");
-            buf.append(" ver=\"");
+        buf.optAttribute("ver", rosterVersion);
-            buf.append(rosterVersion);
+        buf.rightAngelBracket();
-            buf.append('"');
+
-        }
-        buf.append(">");
         synchronized (rosterItems) {
             for (Item entry : rosterItems) {
                 buf.append(entry.toXML());
             }
         }
-        buf.append("</query>");
+        buf.closeElement("query");
-        return buf.toString();
+        return buf;
     }
 
     public String getVersion() {

core/src/main/java/org/jivesoftware/smack/packet/Session.java

@@ -36,7 +36,8 @@ public class Session extends IQ {
         setType(IQ.Type.SET);
     }
 
-    public String getChildElementXML() {
+    @Override
+    public CharSequence getChildElementXML() {
         return "<session xmlns=\"urn:ietf:params:xml:ns:xmpp-session\"/>";
     }
 }

core/src/main/java/org/jivesoftware/smack/packet/XMPPError.java

@@ -152,7 +152,7 @@ public class XMPPError {
      *
      * @return the error as XML.
      */
-    public String toXML() {
+    public CharSequence toXML() {
         StringBuilder buf = new StringBuilder();
         buf.append("<error");
         if (type != null) {

core/src/main/java/org/jivesoftware/smack/util/LazyStringBuilder.java

@@ -0,0 +1,89 @@
+/**
+ *
+ * Copyright 2014 Florian Schmaus
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jivesoftware.smack.util;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class LazyStringBuilder implements Appendable, CharSequence {
+
+    private final List<CharSequence> list;
+    
+    public LazyStringBuilder() {
+        list = new ArrayList<CharSequence>(20);
+    }
+
+    public LazyStringBuilder append(LazyStringBuilder lsb) {
+        list.addAll(lsb.list);
+        return this;
+    }
+
+    @Override
+    public LazyStringBuilder append(CharSequence csq) {
+        assert csq != null;
+        list.add(csq);
+        return this;
+    }
+
+    @Override
+    public LazyStringBuilder append(CharSequence csq, int start, int end) {
+        CharSequence subsequence = csq.subSequence(start, end);
+        list.add(subsequence);
+        return this;
+    }
+
+    @Override
+    public LazyStringBuilder append(char c) {
+        list.add(Character.toString(c));
+        return this;
+    }
+
+    @Override
+    public int length() {
+        int length = 0;
+        for (CharSequence csq : list) {
+            length += csq.length();
+        }
+        return length;
+    }
+
+    @Override
+    public char charAt(int index) {
+        for (CharSequence csq : list) {
+            if (index < csq.length()) {
+                return csq.charAt(index);
+            } else {
+                index -= csq.length();
+            }
+        }
+        throw new IndexOutOfBoundsException();
+    }
+
+    @Override
+    public CharSequence subSequence(int start, int end) {
+        return toString().subSequence(start, end);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder(length());
+        for (CharSequence csq : list) {
+            sb.append(csq);
+        }
+        return sb.toString();
+    }
+}

core/src/main/java/org/jivesoftware/smack/util/StringUtils.java

@@ -290,7 +290,7 @@ public class StringUtils {
      * @param string the string to escape.
      * @return the string with appropriate characters escaped.
      */
-    public static String escapeForXML(final String string) {
+    public static CharSequence escapeForXML(final String string) {
         if (string == null) {
             return null;
         }
@@ -339,7 +339,7 @@ public class StringUtils {
         if (i > last) {
             out.append(input, last, i - last);
         }
-        return out.toString();
+        return out;
     }
 
     /**

core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java

@@ -16,12 +16,20 @@
  */
 package org.jivesoftware.smack.util;
 
-public class XmlStringBuilder implements Appendable, CharSequence {
+import org.jivesoftware.smack.packet.PacketExtension;
 
-    private final StringBuilder sb;
+public class XmlStringBuilder implements Appendable, CharSequence {
+    public static final String RIGHT_ANGEL_BRACKET = Character.toString('>');
+
+    private final LazyStringBuilder sb;
 
     public XmlStringBuilder() {
-        sb = new StringBuilder();
+        sb = new LazyStringBuilder();
+    }
+
+    public XmlStringBuilder(PacketExtension pe) {
+        this();
+        prelude(pe);
     }
 
     /**
@@ -29,11 +37,10 @@ public class XmlStringBuilder implements Appendable, CharSequence {
      *
      * @param name
      * @param content
-     * @return
+     * @return the XmlStringBuilder
      */
     public XmlStringBuilder element(String name, String content) {
-        if (content == null)
+        assert content != null;
-            return this;
         openElement(name);
         escape(content);
         closeElement(name);
@@ -41,8 +48,21 @@ public class XmlStringBuilder implements Appendable, CharSequence {
     }
 
     public XmlStringBuilder element(String name, Enum<?> content) {
-        if (content != null) {
+        assert content != null;
         element(name, content.name());
+        return this;
+    }
+
+    public XmlStringBuilder optElement(String name, String content) {
+        if (content != null) {
+            element(name, content);
+        }
+        return this;
+    }
+
+    public XmlStringBuilder optElement(String name, Enum<?> content) {
+        if (content != null) {
+            element(name, content);
         }
         return this;
     }
@@ -53,54 +73,111 @@ public class XmlStringBuilder implements Appendable, CharSequence {
     }
 
     public XmlStringBuilder openElement(String name) {
-        halfOpenElement(name).append('>');
+        halfOpenElement(name).rightAngelBracket();
         return this;
     }
 
     public XmlStringBuilder closeElement(String name) {
-        sb.append("</").append(name).append('>');
+        sb.append("</").append(name);
+        rightAngelBracket();
         return this;
     }
 
-    public XmlStringBuilder emptyElementClose() {
+    public XmlStringBuilder closeElement(PacketExtension pe) {
+        closeElement(pe.getElementName());
+        return this;
+    }
+
+    public XmlStringBuilder closeEmptyElement() {
         sb.append("/>");
         return this;
     }
 
+    public XmlStringBuilder rightAngelBracket() {
+        sb.append(RIGHT_ANGEL_BRACKET);
+        return this;
+    }
+
     /**
      * Does nothing if value is null.
      *
      * @param name
      * @param value
-     * @return
+     * @return the XmlStringBuilder
      */
     public XmlStringBuilder attribute(String name, String value) {
-        if (value == null)
+        assert value != null;
-            return this;
         sb.append(' ').append(name).append("='");
         escape(value);
         sb.append('\'');
         return this;
     }
 
+    public XmlStringBuilder attribute(String name, Enum<?> value) {
+        assert value != null;
+        attribute(name, value.name());
+        return this;
+    }
+
+    public XmlStringBuilder optAttribute(String name, String value) {
+        if (value != null) {
+            attribute(name, value);
+        }
+        return this;
+    }
+
+    public XmlStringBuilder optAttribute(String name, Enum<?> value) {
+        if (value != null) {
+            attribute(name, value.name());
+        }
+        return this;
+    }
+
     public XmlStringBuilder xmlnsAttribute(String value) {
-        attribute("xmlns", value);
+        optAttribute("xmlns", value);
+        return this;
+    }
+
+    public XmlStringBuilder xmllangAttribute(String value) {
+        optAttribute("xml:lang", value);
         return this;
     }
  
     public XmlStringBuilder escape(String text) {
+        assert text != null;
         sb.append(StringUtils.escapeForXML(text));
         return this;
     }
 
+    public XmlStringBuilder prelude(PacketExtension pe) {
+        halfOpenElement(pe.getElementName());
+        xmlnsAttribute(pe.getNamespace());
+        return this;
+    }
+
+    public XmlStringBuilder optAppend(CharSequence csq) {
+        if (csq != null) {
+            append(csq);
+        }
+        return this;
+    }
+
+    public XmlStringBuilder append(XmlStringBuilder xsb) {
+        assert xsb != null;
+        sb.append(xsb.sb);
+        return this;
+    }
+
     @Override
     public XmlStringBuilder append(CharSequence csq) {
+        assert csq != null;
         sb.append(csq);
         return this;
     }
 
     @Override
     public XmlStringBuilder append(CharSequence csq, int start, int end) {
+        assert csq != null;
         sb.append(csq, start, end);
         return this;
     }

core/src/main/java/org/jivesoftware/smack/util/XmlUtils.java

@@ -1,34 +0,0 @@
-/**
- *
- * Copyright the original author or authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.jivesoftware.smack.util;
-
-/**
- * Simple utility for XML.
- * 
- * @author Robin Collier
- */
-public class XmlUtils {
-
-    static public void appendAttribute(StringBuilder builder, String att, String value) {
-        builder.append(" ");
-        builder.append(att);
-        builder.append("='");
-        builder.append(value);
-        builder.append("'");
-    }
-
-}

core/src/test/java/org/jivesoftware/smack/packet/MessageTest.java

@@ -54,7 +54,7 @@ public class MessageTest {
         Message messageTypeInConstructor = new Message(null, Message.Type.chat);
         messageTypeInConstructor.setPacketID(Packet.ID_NOT_AVAILABLE);
         assertEquals(type, messageTypeInConstructor.getType());
-        assertXMLEqual(control, messageTypeInConstructor.toXML());
+        assertXMLEqual(control, messageTypeInConstructor.toXML().toString());
 
         controlBuilder = new StringBuilder();
         controlBuilder.append("<message")
@@ -67,7 +67,7 @@ public class MessageTest {
         Message messageTypeSet = getNewMessage();
         messageTypeSet.setType(type2);
         assertEquals(type2, messageTypeSet.getType());
-        assertXMLEqual(control, messageTypeSet.toXML());
+        assertXMLEqual(control, messageTypeSet.toXML().toString());
     }
 
     @Test(expected=IllegalArgumentException.class)
@@ -98,7 +98,7 @@ public class MessageTest {
         message.setSubject(messageSubject);
 
         assertEquals(messageSubject, message.getSubject());
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
     }
 
     @Test
@@ -117,7 +117,7 @@ public class MessageTest {
         message.setBody(messageBody);
 
         assertEquals(messageBody, message.getBody());
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
     }
 
     @Test
@@ -150,7 +150,7 @@ public class MessageTest {
         message.addBody(null, messageBody1);
         message.addBody(lang2, messageBody2);
         message.addBody(lang3, messageBody3);
-        Diff xmlDiff = new Diff(control, message.toXML());
+        Diff xmlDiff = new Diff(control, message.toXML().toString());
         xmlDiff.overrideElementQualifier(new RecursiveElementNameAndTextQualifier());
         assertTrue(xmlDiff.similar());
 
@@ -196,7 +196,7 @@ public class MessageTest {
         message.setThread(messageThread);
 
         assertEquals(messageThread, message.getThread());
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
     }
 
     @Test
@@ -214,7 +214,7 @@ public class MessageTest {
         Message message = getNewMessage();
         message.setLanguage(lang);
 
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
     }
 
     @Test

core/src/test/java/org/jivesoftware/smack/packet/PresenceTest.java

@@ -49,7 +49,7 @@ public class PresenceTest {
         Presence presenceTypeInConstructor = new Presence(type);
         presenceTypeInConstructor.setPacketID(Packet.ID_NOT_AVAILABLE);
         assertEquals(type, presenceTypeInConstructor.getType());
-        assertXMLEqual(control, presenceTypeInConstructor.toXML());
+        assertXMLEqual(control, presenceTypeInConstructor.toXML().toString());
 
         controlBuilder = new StringBuilder();
         controlBuilder.append("<presence")
@@ -62,7 +62,7 @@ public class PresenceTest {
         Presence presenceTypeSet = getNewPresence();
         presenceTypeSet.setType(type2);
         assertEquals(type2, presenceTypeSet.getType());
-        assertXMLEqual(control, presenceTypeSet.toXML());
+        assertXMLEqual(control, presenceTypeSet.toXML().toString());
     }
 
     @Test(expected=NullPointerException.class)
@@ -96,7 +96,7 @@ public class PresenceTest {
         presence.setStatus(status);
 
         assertEquals(status, presence.getStatus());
-        assertXMLEqual(control, presence.toXML());
+        assertXMLEqual(control, presence.toXML().toString());
     }
 
     @Test
@@ -115,7 +115,7 @@ public class PresenceTest {
         presence.setPriority(priority);
 
         assertEquals(priority, presence.getPriority());
-        assertXMLEqual(control, presence.toXML());
+        assertXMLEqual(control, presence.toXML().toString());
     }
 
     @Test(expected=IllegalArgumentException.class)
@@ -148,7 +148,7 @@ public class PresenceTest {
                 mode1);
         presenceModeInConstructor.setPacketID(Packet.ID_NOT_AVAILABLE);
         assertEquals(mode1, presenceModeInConstructor.getMode());
-        assertXMLEqual(control, presenceModeInConstructor.toXML());
+        assertXMLEqual(control, presenceModeInConstructor.toXML().toString());
 
         controlBuilder = new StringBuilder();
         controlBuilder.append("<presence>")
@@ -161,7 +161,7 @@ public class PresenceTest {
         Presence presenceModeSet = getNewPresence();
         presenceModeSet.setMode(mode2);
         assertEquals(mode2, presenceModeSet.getMode());
-        assertXMLEqual(control, presenceModeSet.toXML());
+        assertXMLEqual(control, presenceModeSet.toXML().toString());
     }
 
     @Test
@@ -189,7 +189,7 @@ public class PresenceTest {
         Presence presence = getNewPresence();
         presence.setLanguage(lang);
 
-        assertXMLEqual(control, presence.toXML());
+        assertXMLEqual(control, presence.toXML().toString());
     }
 
     private static Presence getNewPresence() {

core/src/test/java/org/jivesoftware/smack/util/PacketParserUtilsTest.java

@@ -75,7 +75,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().isEmpty());
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertNull(message.getBody(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has non-default language, body has no language
         control = XMLBuilder.create("message")
@@ -94,7 +94,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().isEmpty());
         assertEquals(otherLanguage, message.getBody(otherLanguage));
         assertNull(message.getBody(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
         
         // message has no language, body has no language
         control = XMLBuilder.create("message")
@@ -112,7 +112,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().isEmpty());
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertNull(message.getBody(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, body has default language
         control = XMLBuilder.create("message")
@@ -133,7 +133,7 @@ public class PacketParserUtilsTest {
         assertNull(message.getBody(otherLanguage));
 
         // body attribute xml:lang is unnecessary
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has no language, body has non-default language
         control = XMLBuilder.create("message")
@@ -153,7 +153,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().contains(otherLanguage));
         assertEquals(otherLanguage, message.getBody(otherLanguage));
         assertNull(message.getBody(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has default language, body has non-default language
         control = XMLBuilder.create("message")
@@ -174,7 +174,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().contains(otherLanguage));
         assertEquals(otherLanguage, message.getBody(otherLanguage));
         assertNull(message.getBody(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has non-default language, body has default language
         control = XMLBuilder.create("message")
@@ -195,7 +195,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getBodyLanguages().contains(defaultLanguage));
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertNull(message.getBody(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
     }
 
@@ -225,7 +225,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().isEmpty());
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertNull(message.getSubject(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has non-default language, subject has no language
         control = XMLBuilder.create("message")
@@ -244,7 +244,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().isEmpty());
         assertEquals(otherLanguage, message.getSubject(otherLanguage));
         assertNull(message.getSubject(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
         
         // message has no language, subject has no language
         control = XMLBuilder.create("message")
@@ -262,7 +262,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().isEmpty());
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertNull(message.getSubject(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, subject has default language
         control = XMLBuilder.create("message")
@@ -283,7 +283,7 @@ public class PacketParserUtilsTest {
         assertNull(message.getSubject(otherLanguage));
 
         // subject attribute xml:lang is unnecessary
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has no language, subject has non-default language
         control = XMLBuilder.create("message")
@@ -303,7 +303,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().contains(otherLanguage));
         assertEquals(otherLanguage, message.getSubject(otherLanguage));
         assertNull(message.getSubject(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has default language, subject has non-default language
         control = XMLBuilder.create("message")
@@ -324,7 +324,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().contains(otherLanguage));
         assertEquals(otherLanguage, message.getSubject(otherLanguage));
         assertNull(message.getSubject(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has non-default language, subject has default language
         control = XMLBuilder.create("message")
@@ -345,7 +345,7 @@ public class PacketParserUtilsTest {
         assertTrue(message.getSubjectLanguages().contains(defaultLanguage));
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertNull(message.getSubject(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
     }
 
@@ -381,7 +381,7 @@ public class PacketParserUtilsTest {
         assertEquals(2, message.getBodies().size());
         assertEquals(1, message.getBodyLanguages().size());
         assertTrue(message.getBodyLanguages().contains(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has default language, first body no language, second body default language
         control = XMLBuilder.create("message")
@@ -405,7 +405,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertEquals(1, message.getBodies().size());
         assertEquals(0, message.getBodyLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has non-default language, first body no language, second body default language
         control = XMLBuilder.create("message")
@@ -430,7 +430,7 @@ public class PacketParserUtilsTest {
         assertEquals(2, message.getBodies().size());
         assertEquals(1, message.getBodyLanguages().size());
         assertTrue(message.getBodyLanguages().contains(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, first body no language, second body default language
         control = XMLBuilder.create("message")
@@ -453,7 +453,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertEquals(1, message.getBodies().size());
         assertEquals(0, message.getBodyLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has no language, first body no language, second body other language
         control = XMLBuilder.create("message")
@@ -477,7 +477,7 @@ public class PacketParserUtilsTest {
         assertEquals(otherLanguage, message.getBody(otherLanguage));
         assertEquals(2, message.getBodies().size());
         assertEquals(1, message.getBodyLanguages().size());
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, first body no language, second body no language
         control = XMLBuilder.create("message")
@@ -499,7 +499,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getBody(defaultLanguage));
         assertEquals(1, message.getBodies().size());
         assertEquals(0, message.getBodyLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
     }
 
@@ -535,7 +535,7 @@ public class PacketParserUtilsTest {
         assertEquals(2, message.getSubjects().size());
         assertEquals(1, message.getSubjectLanguages().size());
         assertTrue(message.getSubjectLanguages().contains(otherLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has default language, first subject no language, second subject default language
         control = XMLBuilder.create("message")
@@ -559,7 +559,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertEquals(1, message.getSubjects().size());
         assertEquals(0, message.getSubjectLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has non-default language, first subject no language, second subject default language
         control = XMLBuilder.create("message")
@@ -584,7 +584,7 @@ public class PacketParserUtilsTest {
         assertEquals(2, message.getSubjects().size());
         assertEquals(1, message.getSubjectLanguages().size());
         assertTrue(message.getSubjectLanguages().contains(defaultLanguage));
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, first subject no language, second subject default language
         control = XMLBuilder.create("message")
@@ -607,7 +607,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertEquals(1, message.getSubjects().size());
         assertEquals(0, message.getSubjectLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
         // message has no language, first subject no language, second subject other language
         control = XMLBuilder.create("message")
@@ -631,7 +631,7 @@ public class PacketParserUtilsTest {
         assertEquals(otherLanguage, message.getSubject(otherLanguage));
         assertEquals(2, message.getSubjects().size());
         assertEquals(1, message.getSubjectLanguages().size());
-        assertXMLEqual(control, message.toXML());
+        assertXMLEqual(control, message.toXML().toString());
 
         // message has no language, first subject no language, second subject no language
         control = XMLBuilder.create("message")
@@ -653,7 +653,7 @@ public class PacketParserUtilsTest {
         assertEquals(defaultLanguage, message.getSubject(defaultLanguage));
         assertEquals(1, message.getSubjects().size());
         assertEquals(0, message.getSubjectLanguages().size());
-        assertXMLNotEqual(control, message.toXML());
+        assertXMLNotEqual(control, message.toXML().toString());
 
     }
 
@@ -679,9 +679,9 @@ public class PacketParserUtilsTest {
                             + "Bad Message Body</span>";
             assertEquals(body, message.getBody());
             
-            assertXMLNotEqual(control, message.toXML());
+            assertXMLNotEqual(control, message.toXML().toString());
             
-            DetailedDiff diffs = new DetailedDiff(new Diff(control, message.toXML()));
+            DetailedDiff diffs = new DetailedDiff(new Diff(control, message.toXML().toString()));
             
             // body has no namespace URI, span is escaped 
             assertEquals(6, diffs.getAllDifferences().size());
@@ -754,7 +754,7 @@ public class PacketParserUtilsTest {
             .asString(outputProperties);
         
         Packet message = PacketParserUtils.parseMessage(TestUtils.getMessageParser(control));
-        Diff xmlDiff = new Diff(control, message.toXML());
+        Diff xmlDiff = new Diff(control, message.toXML().toString());
         xmlDiff.overrideElementQualifier(new RecursiveElementNameAndTextQualifier());
         assertTrue(xmlDiff.similar());
     }
@@ -765,7 +765,7 @@ public class PacketParserUtilsTest {
     	
     	Presence presence = PacketParserUtils.parsePresence(TestUtils.getPresenceParser(stanza));
     	
-    	assertXMLEqual(stanza, presence.toXML());
+    	assertXMLEqual(stanza, presence.toXML().toString());
     }
     
     @SuppressWarnings("deprecation")
@@ -775,7 +775,7 @@ public class PacketParserUtilsTest {
     	
     	Presence presence = PacketParserUtils.parsePresence(TestUtils.getPresenceParser(stanza));
     	
-    	assertXMLEqual(stanza, presence.toXML());
+    	assertXMLEqual(stanza, presence.toXML().toString());
     	assertEquals(Presence.Type.unsubscribed, presence.getType());
     }
     
@@ -789,7 +789,7 @@ public class PacketParserUtilsTest {
     			+ "</presence>";
     	
     	Presence presence = PacketParserUtils.parsePresence(TestUtils.getPresenceParser(stanza));
-    	assertXMLEqual(stanza, presence.toXML());
+    	assertXMLEqual(stanza, presence.toXML().toString());
     	assertEquals(Presence.Type.unsubscribed, presence.getType());
     	assertEquals("dnd", presence.getMode().name());
     	assertEquals("en", presence.getLanguage());

core/src/test/java/org/jivesoftware/smack/util/StringUtilsTest.java

@@ -35,37 +35,41 @@ public class StringUtilsTest  {
         assertNull(StringUtils.escapeForXML(null));
 
         input = "<b>";
-        assertEquals("&lt;b&gt;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&lt;b&gt;", StringUtils.escapeForXML(input));
 
         input = "\"";
-        assertEquals("&quot;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&quot;", StringUtils.escapeForXML(input));
 
         input = "&";
-        assertEquals("&amp;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&amp;", StringUtils.escapeForXML(input));
 
         input = "<b>\n\t\r</b>";
-        assertEquals("&lt;b&gt;\n\t\r&lt;/b&gt;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&lt;b&gt;\n\t\r&lt;/b&gt;", StringUtils.escapeForXML(input));
 
         input = "   &   ";
-        assertEquals("   &amp;   ", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("   &amp;   ", StringUtils.escapeForXML(input));
 
         input = "   \"   ";
-        assertEquals("   &quot;   ", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("   &quot;   ", StringUtils.escapeForXML(input));
 
         input = "> of me <";
-        assertEquals("&gt; of me &lt;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&gt; of me &lt;", StringUtils.escapeForXML(input));
 
         input = "> of me & you<";
-        assertEquals("&gt; of me &amp; you&lt;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&gt; of me &amp; you&lt;", StringUtils.escapeForXML(input));
 
         input = "& <";
-        assertEquals("&amp; &lt;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&amp; &lt;", StringUtils.escapeForXML(input));
 
         input = "&";
-        assertEquals("&amp;", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("&amp;", StringUtils.escapeForXML(input));
         
         input = "It's a good day today";
-        assertEquals("It&apos;s a good day today", StringUtils.escapeForXML(input));
+        assertCharSequenceEquals("It&apos;s a good day today", StringUtils.escapeForXML(input));
+    }
+
+	public static void assertCharSequenceEquals(CharSequence expected, CharSequence actual) {
+	    assertEquals(expected.toString(), actual.toString());
 	}
 
 	@Test

debug/src/main/java/org/jivesoftware/smackx/debugger/EnhancedDebugger.java

@@ -801,7 +801,7 @@ public class EnhancedDebugger implements SmackDebugger {
 
                 messagesTable.addRow(
                         new Object[]{
-                                formatXML(packet.toXML()),
+                                formatXML(packet.toXML().toString()),
                                 dateFormatter.format(new Date()),
                                 packetReceivedIcon,
                                 packetTypeIcon,
@@ -862,7 +862,7 @@ public class EnhancedDebugger implements SmackDebugger {
 
                 messagesTable.addRow(
                         new Object[]{
-                                formatXML(packet.toXML()),
+                                formatXML(packet.toXML().toString()),
                                 dateFormatter.format(new Date()),
                                 packetSentIcon,
                                 packetTypeIcon,

extensions/src/main/java/org/jivesoftware/smackx/address/MultipleRecipientManager.java

@@ -336,7 +336,7 @@ public class MultipleRecipientManager {
      */
     private static class PacketCopy extends Packet {
 
-        private String text;
+        private CharSequence text;
 
         /**
          * Create a copy of a packet with the text to send. The passed text must be a valid text to
@@ -344,11 +344,12 @@ public class MultipleRecipientManager {
          *
          * @param text the whole text of the packet to send
          */
-        public PacketCopy(String text) {
+        public PacketCopy(CharSequence text) {
             this.text = text;
         }
 
-        public String toXML() {
+        @Override
+        public CharSequence toXML() {
             return text;
         }
 

extensions/src/main/java/org/jivesoftware/smackx/caps/cache/SimpleDirectoryPersistentCache.java

@@ -128,7 +128,7 @@ public class SimpleDirectoryPersistentCache implements EntityCapsPersistentCache
     private static void writeInfoToFile(File file, DiscoverInfo info) throws IOException {
         DataOutputStream dos = new DataOutputStream(new FileOutputStream(file));
         try {
-            dos.writeUTF(info.toXML());
+            dos.writeUTF(info.toXML().toString());
         } finally {
             dos.close();
         }

extensions/src/main/java/org/jivesoftware/smackx/caps/packet/CapsExtension.java

@@ -17,6 +17,7 @@
 package org.jivesoftware.smackx.caps.packet;
 
 import org.jivesoftware.smack.packet.PacketExtension;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 import org.jivesoftware.smackx.caps.EntityCapsManager;
 
 public class CapsExtension implements PacketExtension {
@@ -56,10 +57,10 @@ public class CapsExtension implements PacketExtension {
      *  ver='QgayPKawpkPSDYmwT/WM94uAlu0='/>
      *
      */
-    public String toXML() {
+    public CharSequence toXML() {
-        return "<" + EntityCapsManager.ELEMENT + " xmlns=\"" + EntityCapsManager.NAMESPACE + "\" " +
+        XmlStringBuilder xml = new XmlStringBuilder(this);
-            "hash=\"" + hash + "\" " +
+        xml.attribute("hash", hash).attribute("node", node).attribute("ver", ver);
-            "node=\"" + node + "\" " +
+        xml.closeEmptyElement();
-            "ver=\"" + ver + "\"/>";
+        return xml;
     }
 }

extensions/src/main/java/org/jivesoftware/smackx/disco/packet/DiscoverInfo.java

@@ -18,7 +18,7 @@
 package org.jivesoftware.smackx.disco.packet;
 
 import org.jivesoftware.smack.packet.IQ;
-import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -186,29 +186,27 @@ public class DiscoverInfo extends IQ {
         return false;
     }
 
-    public String getChildElementXML() {
+    @Override
-        StringBuilder buf = new StringBuilder();
+    public CharSequence getChildElementXML() {
-        buf.append("<query xmlns=\"" + NAMESPACE + "\"");
+        XmlStringBuilder xml = new XmlStringBuilder();
-        if (getNode() != null) {
+        xml.halfOpenElement("query");
-            buf.append(" node=\"");
+        xml.xmlnsAttribute(NAMESPACE);
-            buf.append(StringUtils.escapeForXML(getNode()));
+        xml.optAttribute("node", getNode());
-            buf.append("\"");
+        xml.rightAngelBracket();
-        }
-        buf.append(">");
         synchronized (identities) {
             for (Identity identity : identities) {
-                buf.append(identity.toXML());
+                xml.append(identity.toXML());
             }
         }
         synchronized (features) {
             for (Feature feature : features) {
-                buf.append(feature.toXML());
+                xml.append(feature.toXML());
             }
         }
         // Add packet extensions, if any are defined.
-        buf.append(getExtensionsXML());
+        xml.append(getExtensionsXML());
-        buf.append("</query>");
+        xml.closeElement("query");
-        return buf.toString();
+        return xml;
     }
 
     /**
@@ -358,22 +356,15 @@ public class DiscoverInfo extends IQ {
             return lang;
         }
 
-        public String toXML() {
+        public XmlStringBuilder toXML() {
-            StringBuilder buf = new StringBuilder();
+            XmlStringBuilder xml = new XmlStringBuilder();
-            buf.append("<identity");
+            xml.halfOpenElement("identity");
-            // Check if this packet has 'lang' set and maybe append it to the resulting string
+            xml.xmllangAttribute(lang);
-            if (lang != null)
+            xml.attribute("category", category);
-                buf.append(" xml:lang=\"").append(StringUtils.escapeForXML(lang)).append("\"");
+            xml.attribute("name", name);
-            // Category must always be set
+            xml.optAttribute("type", type);
-            buf.append(" category=\"").append(StringUtils.escapeForXML(category)).append("\"");
+            xml.closeEmptyElement();
-            // Name must always be set
+            return xml;
-            buf.append(" name=\"").append(StringUtils.escapeForXML(name)).append("\"");
-            // Check if this packet has 'type' set and maybe append it to the resulting string
-            if (type != null) {
-                buf.append(" type=\"").append(StringUtils.escapeForXML(type)).append("\"");
-            }
-            buf.append("/>");
-            return buf.toString();
         }
 
         /** 
@@ -488,10 +479,12 @@ public class DiscoverInfo extends IQ {
             return variable;
         }
 
-        public String toXML() {
+        public XmlStringBuilder toXML() {
-            StringBuilder buf = new StringBuilder();
+            XmlStringBuilder xml = new XmlStringBuilder();
-            buf.append("<feature var=\"").append(StringUtils.escapeForXML(variable)).append("\"/>");
+            xml.halfOpenElement("feature");
-            return buf.toString();
+            xml.attribute("var", variable);
+            xml.closeEmptyElement();
+            return xml;
         }
 
         public boolean equals(Object obj) {

extensions/src/main/java/org/jivesoftware/smackx/disco/packet/DiscoverItems.java

@@ -18,7 +18,7 @@
 package org.jivesoftware.smackx.disco.packet;
 
 import org.jivesoftware.smack.packet.IQ;
-import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.util.Collection;
 import java.util.Collections;
@@ -102,22 +102,20 @@ public class DiscoverItems extends IQ {
         this.node = node;
     }
 
-    public String getChildElementXML() {
+    public XmlStringBuilder getChildElementXML() {
-        StringBuilder buf = new StringBuilder();
+        XmlStringBuilder xml = new XmlStringBuilder();
-        buf.append("<query xmlns=\"" + NAMESPACE + "\"");
+        xml.halfOpenElement("query");
-        if (getNode() != null) {
+        xml.xmlnsAttribute(NAMESPACE);
-            buf.append(" node=\"");
+        xml.optAttribute("node", getNode());
-            buf.append(StringUtils.escapeForXML(getNode()));
+        xml.rightAngelBracket();
-            buf.append("\"");
+
-        }
-        buf.append(">");
         synchronized (items) {
             for (Item item : items) {
-                buf.append(item.toXML());
+                xml.append(item.toXML());
             }
         }
-        buf.append("</query>");
+        xml.closeElement("query");
-        return buf.toString();
+        return xml;
     }
 
     /**
@@ -231,20 +229,15 @@ public class DiscoverItems extends IQ {
             this.action = action;
         }
 
-        public String toXML() {
+        public XmlStringBuilder toXML() {
-            StringBuilder buf = new StringBuilder();
+            XmlStringBuilder xml = new XmlStringBuilder();
-            buf.append("<item jid=\"").append(entityID).append("\"");
+            xml.halfOpenElement("item");
-            if (name != null) {
+            xml.attribute("jid", entityID);
-                buf.append(" name=\"").append(StringUtils.escapeForXML(name)).append("\"");
+            xml.optAttribute("name", name);
-            }
+            xml.optAttribute("node", node);
-            if (node != null) {
+            xml.optAttribute("action", action);
-                buf.append(" node=\"").append(StringUtils.escapeForXML(node)).append("\"");
+            xml.closeEmptyElement();
-            }
+            return xml;
-            if (action != null) {
-                buf.append(" action=\"").append(StringUtils.escapeForXML(action)).append("\"");
-            }
-            buf.append("/>");
-            return buf.toString();
         }
     }
 }

extensions/src/main/java/org/jivesoftware/smackx/pubsub/AffiliationsExtension.java

@@ -46,7 +46,7 @@ public class AffiliationsExtension extends NodeExtension
 	}
 
 	@Override
-	public String toXML()
+	public CharSequence toXML()
 	{
 		if ((items == null) || (items.size() == 0))
 		{

extensions/src/main/java/org/jivesoftware/smackx/pubsub/FormNode.java

@@ -73,7 +73,7 @@ public class FormNode extends NodeExtension
 	}
 	
 	@Override
-	public String toXML()
+	public CharSequence toXML()
 	{
 		if (configForm == null)
 		{

extensions/src/main/java/org/jivesoftware/smackx/pubsub/ItemsExtension.java

@@ -151,7 +151,7 @@ public class ItemsExtension extends NodeExtension implements EmbeddedPacketExten
 	}
 	
 	@Override
-	public String toXML()
+	public CharSequence toXML()
 	{
 		if ((items == null) || (items.size() == 0))
 		{

extensions/src/main/java/org/jivesoftware/smackx/pubsub/NodeExtension.java

@@ -75,7 +75,7 @@ public class NodeExtension implements PacketExtension
 		return element.getNamespace().getXmlns();
 	}
 
-	public String toXML()
+	public CharSequence toXML()
 	{
 		return '<' + getElementName() + (node == null ? "" : " node='" + node + '\'') + "/>";
 	}

extensions/src/main/java/org/jivesoftware/smackx/pubsub/OptionsExtension.java

@@ -16,7 +16,7 @@
  */
 package org.jivesoftware.smackx.pubsub;
 
-import org.jivesoftware.smack.util.XmlUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 /**
  * A packet extension representing the <b>options</b> element. 
@@ -56,20 +56,13 @@ public class OptionsExtension extends NodeExtension
 	}
 
     @Override
-	public String toXML()
+    public XmlStringBuilder toXML() {
-	{
+        XmlStringBuilder xml = new XmlStringBuilder();
-		StringBuilder builder = new StringBuilder("<");
+        xml.halfOpenElement(getElementName());
-		builder.append(getElementName());
+        xml.attribute("jid", jid);
-		XmlUtils.appendAttribute(builder, "jid", jid);
+        xml.optAttribute("node", getNode());
-		
+        xml.optAttribute("subid", id);
-		if (getNode() != null)
+        xml.closeEmptyElement();
-			XmlUtils.appendAttribute(builder, "node", getNode());
+        return xml;
-		
-		if (id != null)
-			XmlUtils.appendAttribute(builder, "subid", id);
-		
-		builder.append("/>");
-		return builder.toString();
     }
-
 }

extensions/src/main/java/org/jivesoftware/smackx/pubsub/SubscriptionsExtension.java

@@ -66,7 +66,7 @@ public class SubscriptionsExtension extends NodeExtension
 	}
 
 	@Override
-	public String toXML()
+	public CharSequence toXML()
 	{
 		if ((items == null) || (items.size() == 0))
 		{

extensions/src/main/java/org/jivesoftware/smackx/pubsub/UnsubscribeExtension.java

@@ -16,7 +16,7 @@
  */
 package org.jivesoftware.smackx.pubsub;
 
-import org.jivesoftware.smack.util.XmlUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 
 /**
@@ -57,20 +57,13 @@ public class UnsubscribeExtension extends NodeExtension
 	}
 
     @Override
-	public String toXML()
+    public XmlStringBuilder toXML() {
-	{
+        XmlStringBuilder xml = new XmlStringBuilder();
-		StringBuilder builder = new StringBuilder("<");
+        xml.halfOpenElement(getElementName());
-		builder.append(getElementName());
+        xml.attribute("jid", jid);
-		XmlUtils.appendAttribute(builder, "jid", jid);
+        xml.optAttribute("node", getNode());
-		
+        xml.optAttribute("subid", id);
-		if (getNode() != null)
+        xml.closeEmptyElement();
-			XmlUtils.appendAttribute(builder, "node", getNode());
+        return xml;
-		
-		if (id != null)
-			XmlUtils.appendAttribute(builder, "subid", id);
-		
-		builder.append("/>");
-		return builder.toString();
     }
-
 }

extensions/src/main/java/org/jivesoftware/smackx/vcardtemp/packet/VCard.java

@@ -844,11 +844,11 @@ public class VCard extends IQ {
             appendTag(tag, null, null, hasContent, builder);
         }
 
-        private void appendTag(String tag, final String tagText) {
+        private void appendTag(String tag, final CharSequence tagText) {
             if (tagText == null) return;
             final ContentBuilder contentBuilder = new ContentBuilder() {
                 public void addTagContent() {
-                    sb.append(tagText.trim());
+                    sb.append(tagText.toString().trim());
                 }
             };
             appendTag(tag, true, contentBuilder);

extensions/src/main/java/org/jivesoftware/smackx/xdata/FormField.java

@@ -18,6 +18,7 @@
 package org.jivesoftware.smackx.xdata;
 
 import org.jivesoftware.smack.util.StringUtils;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -264,15 +265,13 @@ public class FormField {
     }
 
     public String toXML() {
-        StringBuilder buf = new StringBuilder();
+        XmlStringBuilder buf = new XmlStringBuilder();
         buf.append("<field");
         // Add attributes
         if (getLabel() != null) {
             buf.append(" label=\"").append(getLabel()).append("\"");
         }
-        if (getVariable() != null) {
+        buf.attribute("var", getVariable());
-            buf.append(" var=\"").append(getVariable()).append("\"");
-        }
         if (getType() != null) {
             buf.append(" type=\"").append(getType()).append("\"");
         }
@@ -286,7 +285,7 @@ public class FormField {
         }
         // Loop through all the values and append them to the string buffer
         for (Iterator<String> i = getValues(); i.hasNext();) {
-            buf.append("<value>").append(i.next()).append("</value>");
+            buf.element("value", i.next());
         }
         // Loop through all the values and append them to the string buffer
         for (Iterator<Option> i = getOptions(); i.hasNext();) {

extensions/src/test/java/org/jivesoftware/smackx/bytestreams/ibb/packet/CloseTest.java

@@ -78,7 +78,7 @@ public class CloseTest {
         close.setTo("juliet@capulet.lit/balcony");
         close.setPacketID("us71g45j");
         
-        assertXMLEqual(control, close.toXML());
+        assertXMLEqual(control, close.toXML().toString());
     }
 
 }

extensions/src/test/java/org/jivesoftware/smackx/bytestreams/ibb/packet/DataTest.java

@@ -83,7 +83,7 @@ public class DataTest {
         data.setTo("juliet@capulet.lit/balcony");
         data.setPacketID("kr91n475");
         
-        assertXMLEqual(control, data.toXML());
+        assertXMLEqual(control, data.toXML().toString());
     }
 
 }

extensions/src/test/java/org/jivesoftware/smackx/bytestreams/ibb/packet/OpenTest.java

@@ -100,7 +100,7 @@ public class OpenTest {
         open.setTo("juliet@capulet.lit/balcony");
         open.setPacketID("jn3h8g65");
         
-        assertXMLEqual(control, open.toXML());
+        assertXMLEqual(control, open.toXML().toString());
     }
     
     

extensions/src/test/java/org/jivesoftware/smackx/caps/EntityCapsManagerTest.java

@@ -101,7 +101,7 @@ public class EntityCapsManagerTest {
 
         DiscoverInfo restored_di = EntityCapsManager.getDiscoveryInfoByNodeVer(nodeVer);
         assertNotNull(restored_di);
-        assertEquals(di.toXML(), restored_di.toXML());
+        assertEquals(di.toXML().toString(), restored_di.toXML().toString());
     }
 
     private static DiscoverInfo createComplexSamplePacket() {

extensions/src/test/java/org/jivesoftware/smackx/filetransfer/FileTransferNegotiatorTest.java

@@ -50,6 +50,7 @@ public class FileTransferNegotiatorTest {
         FileTransferNegotiator fileNeg = FileTransferNegotiator.getInstanceFor(connection);
         fileNeg.negotiateOutgoingTransfer("me", "streamid", "file", 1024, null, 10);
         Packet packet = connection.getSentPacket();
-        assertTrue(packet.toXML().indexOf("\"stream-method\" type=\"list-single\"") != -1);
+        String xml = packet.toXML().toString();
+        assertTrue(xml.indexOf("var='stream-method' type=\"list-single\"") != -1);
     }
 }

extensions/src/test/java/org/jivesoftware/util/Protocol.java

@@ -135,10 +135,10 @@ public class Protocol {
 
             if (printProtocol) {
                 System.out.println("------------------- Request -------------\n");
-                System.out.println(prettyFormat(request.toXML()));
+                System.out.println(prettyFormat(request.toXML().toString()));
                 System.out.println("------------------- Response ------------\n");
                 if (response != null) {
-                    System.out.println(prettyFormat(response.toXML()));
+                    System.out.println(prettyFormat(response.toXML().toString()));
                 }
                 else {
                     System.out.println("No response");

legacy/src/main/java/org/jivesoftware/smackx/workgroup/agent/AgentSession.java

@@ -786,9 +786,6 @@ public class AgentSession {
      * @throws NotConnectedException 
      */
     public void setNote(String sessionID, String note) throws NoResponseException, XMPPErrorException, NotConnectedException  {
-        note = ChatNotes.replace(note, "\n", "\\n");
-        note = StringUtils.escapeForXML(note);
-
         ChatNotes notes = new ChatNotes();
         notes.setType(IQ.Type.SET);
         notes.setTo(workgroupJID);

legacy/src/main/java/org/jivesoftware/smackx/workgroup/ext/notes/ChatNotes.java

@@ -19,6 +19,7 @@ package org.jivesoftware.smackx.workgroup.ext.notes;
 
 import org.jivesoftware.smack.packet.IQ;
 import org.jivesoftware.smack.provider.IQProvider;
+import org.jivesoftware.smack.util.XmlStringBuilder;
 import org.xmlpull.v1.XmlPullParser;
 
 /**
@@ -57,13 +58,13 @@ public class ChatNotes extends IQ {
     }
 
     public String getChildElementXML() {
-        StringBuilder buf = new StringBuilder();
+        XmlStringBuilder buf = new XmlStringBuilder();
 
         buf.append("<").append(ELEMENT_NAME).append(" xmlns=\"").append(NAMESPACE).append("\">");
         buf.append("<sessionID>").append(getSessionID()).append("</sessionID>");
 
         if (getNotes() != null) {
-            buf.append("<notes>").append(getNotes()).append("</notes>");
+            buf.element("notes", getNotes());
         }
         buf.append("</").append(ELEMENT_NAME).append("> ");
 

legacy/src/main/java/org/jivesoftware/smackx/workgroup/user/Workgroup.java

@@ -374,13 +374,10 @@ public class Workgroup {
             String name = iter.next();
             String value = metadata.get(name).toString();
 
-            String escapedName = StringUtils.escapeForXML(name);
+            FormField field = new FormField(name);
-            String escapedValue = StringUtils.escapeForXML(value);
-
-            FormField field = new FormField(escapedName);
             field.setType(FormField.TYPE_TEXT_SINGLE);
             form.addField(field);
-            form.setAnswer(escapedName, escapedValue);
+            form.setAnswer(name, value);
         }
         joinQueue(form, userID);
     }

tcp/src/main/java/org/jivesoftware/smack/PacketWriter.java

@@ -146,7 +146,7 @@ class PacketWriter {
             while (!done && (writerThread == thisThread)) {
                 Packet packet = nextPacket();
                 if (packet != null) {
-                    writer.write(packet.toXML());
+                    writer.write(packet.toXML().toString());
 
                     if (queue.isEmpty()) {
                         writer.flush();
@@ -159,7 +159,7 @@ class PacketWriter {
             try {
                 while (!queue.isEmpty()) {
                     Packet packet = queue.remove();
-                    writer.write(packet.toXML());
+                    writer.write(packet.toXML().toString());
                 }
                 writer.flush();
             }