Improve Privacy List code

notably add a cache for the active and default privacy list to avoid
IQ get/response round-trips.

Also add a few methods to PrivacyListManager to get the privacy list
names. The already existing methods always returned the whole list
together with the name, which caused two round-trips.

Simplified some code.

Properly escape Privacy XML.

smack-core/src/main/java/org/jivesoftware/smack/AbstractXMPPConnection.java

@@ -1371,6 +1371,27 @@ public abstract class AbstractXMPPConnection implements XMPPConnection {
         sendStanzaWithResponseCallback(iqRequest, replyFilter, callback, exceptionCallback, timeout);
     }
 
+    @Override
+    public void addOneTimeSyncCallback(final PacketListener callback, final PacketFilter packetFilter) {
+        final PacketListener packetListener = new PacketListener() {
+            @Override
+            public void processPacket(Packet packet) throws NotConnectedException {
+                try {
+                    callback.processPacket(packet);
+                } finally {
+                    removeSyncPacketListener(this);
+                }
+            }
+        };
+        addSyncPacketListener(packetListener, packetFilter);
+        removeCallbacksService.schedule(new Runnable() {
+            @Override
+            public void run() {
+                removeSyncPacketListener(packetListener);
+            }
+        }, getPacketReplyTimeout(), TimeUnit.MILLISECONDS);
+    }
+
     private long lastStanzaReceived;
 
     public long getLastStanzaReceived() {

smack-core/src/main/java/org/jivesoftware/smack/XMPPConnection.java

@@ -556,6 +556,15 @@ public interface XMPPConnection {
                     final ExceptionCallback exceptionCallback, long timeout)
                     throws NotConnectedException;
 
+    /**
+     * Add a callback that is called exactly once and synchronously with the incoming stanza that matches the given
+     * packet filter.
+     * 
+     * @param callback the callback invoked once the packet filter matches a stanza.
+     * @param packetFilter the filter to match stanzas or null to match all.
+     */
+    public void addOneTimeSyncCallback(PacketListener callback, PacketFilter packetFilter);
+
     /**
      * Returns the timestamp in milliseconds when the last stanza was received.
      * 

smack-core/src/main/java/org/jivesoftware/smack/filter/IQResultReplyFilter.java

@@ -0,0 +1,41 @@
+/**
+ *
+ * Copyright 2015 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.filter;
+
+import org.jivesoftware.smack.XMPPConnection;
+import org.jivesoftware.smack.packet.IQ;
+import org.jivesoftware.smack.packet.Packet;
+
+/**
+ *
+ */
+public class IQResultReplyFilter extends IQReplyFilter {
+
+
+    public IQResultReplyFilter(IQ iqPacket, XMPPConnection conn) {
+        super(iqPacket, conn);
+    }
+
+    @Override
+    public boolean accept(Packet packet) {
+        if (!super.accept(packet)) {
+            return false;
+        }
+        return IQTypeFilter.RESULT.accept(packet);
+    }
+
+}

smack-extensions/src/main/java/org/jivesoftware/smackx/privacy/PrivacyList.java

@@ -70,4 +70,8 @@ public class PrivacyList {
         return items;
     }
 
+    @Override
+    public String toString() {
+        return "Privacy List: " + listName + "(active:" + isActiveList + ", default:" + isDefaultList + ")";
+    }
 }

smack-extensions/src/main/java/org/jivesoftware/smackx/privacy/PrivacyListManager.java

@@ -23,6 +23,7 @@ import java.util.Set;
 import java.util.WeakHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
 
+import org.jivesoftware.smack.AbstractConnectionListener;
 import org.jivesoftware.smack.SmackException.NoResponseException;
 import org.jivesoftware.smack.SmackException.NotConnectedException;
 import org.jivesoftware.smack.XMPPConnection;
@@ -32,25 +33,29 @@ import org.jivesoftware.smack.PacketListener;
 import org.jivesoftware.smack.XMPPConnectionRegistry;
 import org.jivesoftware.smack.XMPPException.XMPPErrorException;
 import org.jivesoftware.smack.filter.AndFilter;
+import org.jivesoftware.smack.filter.IQResultReplyFilter;
 import org.jivesoftware.smack.filter.IQTypeFilter;
 import org.jivesoftware.smack.filter.PacketFilter;
 import org.jivesoftware.smack.filter.PacketTypeFilter;
 import org.jivesoftware.smack.packet.IQ;
 import org.jivesoftware.smack.packet.Packet;
 import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
+import org.jivesoftware.smackx.privacy.filter.SetActiveListFilter;
+import org.jivesoftware.smackx.privacy.filter.SetDefaultListFilter;
 import org.jivesoftware.smackx.privacy.packet.Privacy;
 import org.jivesoftware.smackx.privacy.packet.PrivacyItem;
 
 /**
  * A PrivacyListManager is used by XMPP clients to block or allow communications from other
- * users. Use the manager to: <ul>
+ * users. Use the manager to:
+ * <ul>
  *      <li>Retrieve privacy lists.
  *      <li>Add, remove, and edit privacy lists.
  *      <li>Set, change, or decline active lists.
  *      <li>Set, change, or decline the default list (i.e., the list that is active by default).
  * </ul>
  * Privacy Items can handle different kind of permission communications based on JID, group, 
- * subscription type or globally (@see PrivacyItem).
+ * subscription type or globally (see {@link PrivacyItem}).
  * 
  * @author Francisco Vives
  * @see <a href="http://xmpp.org/extensions/xep-0016.html">XEP-16: Privacy Lists</a>
@@ -58,8 +63,11 @@ import org.jivesoftware.smackx.privacy.packet.PrivacyItem;
 public class PrivacyListManager extends Manager {
     public static final String NAMESPACE = Privacy.NAMESPACE;
 
-    private static final PacketFilter PACKET_FILTER = new AndFilter(IQTypeFilter.SET,
+    public static final PacketFilter PRIVACY_FILTER = new PacketTypeFilter(Privacy.class);
-                    new PacketTypeFilter(Privacy.class));
+
+    private static final PacketFilter PRIVACY_SET = new AndFilter(IQTypeFilter.SET, PRIVACY_FILTER);
+
+    private static final PacketFilter PRIVACY_RESULT = new AndFilter(IQTypeFilter.RESULT, PRIVACY_FILTER);
 
     // Keep the list of instances of this class.
     private static final Map<XMPPConnection, PrivacyListManager> INSTANCES = new WeakHashMap<XMPPConnection, PrivacyListManager>();
@@ -75,6 +83,10 @@ public class PrivacyListManager extends Manager {
         });
     }
 
+    // TODO implement: private final Map<String, PrivacyList> cachedPrivacyLists = new HashMap<>();
+    private volatile String cachedActiveListName;
+    private volatile String cachedDefaultListName;
+
     /**
      * Creates a new privacy manager to maintain the communication privacy. Note: no
      * information is sent to or received from the server until you attempt to 
@@ -82,7 +94,7 @@ public class PrivacyListManager extends Manager {
      *
      * @param connection the XMPP connection.
      */
-	private PrivacyListManager(final XMPPConnection connection) {
+	private PrivacyListManager(XMPPConnection connection) {
         super(connection);
 
         connection.addSyncPacketListener(new PacketListener() {
@@ -109,7 +121,78 @@ public class PrivacyListManager extends Manager {
                 IQ iq = IQ.createResultIQ(privacy);
                 connection().sendPacket(iq);
             }
-        }, PACKET_FILTER);
+        }, PRIVACY_SET);
+
+        // cached(Active|Default)ListName handling
+        connection.addPacketSendingListener(new PacketListener() {
+            @Override
+            public void processPacket(Packet packet) throws NotConnectedException {
+                XMPPConnection connection = connection();
+                Privacy privacy = (Privacy) packet;
+                PacketFilter iqResultReplyFilter = new IQResultReplyFilter(privacy, connection);
+                final String activeListName = privacy.getActiveName();
+                final boolean declinceActiveList = privacy.isDeclineActiveList();
+                connection.addOneTimeSyncCallback(new PacketListener() {
+                    @Override
+                    public void processPacket(Packet packet) throws NotConnectedException {
+                            if (declinceActiveList) {
+                                cachedActiveListName = null;
+                            }
+                            else {
+                                cachedActiveListName = activeListName;
+                            }
+                            return;
+                    }
+                }, iqResultReplyFilter);
+            }
+        }, SetActiveListFilter.INSTANCE);
+        connection.addPacketSendingListener(new PacketListener() {
+            @Override
+            public void processPacket(Packet packet) throws NotConnectedException {
+                XMPPConnection connection = connection();
+                Privacy privacy = (Privacy) packet;
+                PacketFilter iqResultReplyFilter = new IQResultReplyFilter(privacy, connection);
+                final String defaultListName = privacy.getDefaultName();
+                final boolean declinceDefaultList = privacy.isDeclineDefaultList();
+                connection.addOneTimeSyncCallback(new PacketListener() {
+                    @Override
+                    public void processPacket(Packet packet) throws NotConnectedException {
+                            if (declinceDefaultList) {
+                                cachedDefaultListName = null;
+                            }
+                            else {
+                                cachedDefaultListName = defaultListName;
+                            }
+                            return;
+                    }
+                }, iqResultReplyFilter);
+            }
+        }, SetDefaultListFilter.INSTANCE);
+        connection.addSyncPacketListener(new PacketListener() {
+            @Override
+            public void processPacket(Packet packet) throws NotConnectedException {
+                Privacy privacy = (Privacy) packet;
+                // If a privacy IQ result stanza has an active or default list name set, then we use that
+                // as cached list name.
+                String activeList = privacy.getActiveName();
+                if (activeList != null) {
+                    cachedActiveListName = activeList;
+                }
+                String defaultList = privacy.getDefaultName();
+                if (defaultList != null) {
+                    cachedDefaultListName = defaultList;
+                }
+            }
+        }, PRIVACY_RESULT);
+        connection.addConnectionListener(new AbstractConnectionListener() {
+            @Override
+            public void reconnectionSuccessful() {
+                cachedActiveListName = cachedDefaultListName = null;
+            }
+        });
+
+        // XEP-0016 § 3.
+        ServiceDiscoveryManager.getInstanceFor(connection).addFeature(NAMESPACE);
     }
 
     /**
@@ -191,13 +274,26 @@ public class PrivacyListManager extends Manager {
     public PrivacyList getActiveList() throws NoResponseException, XMPPErrorException, NotConnectedException  {
         Privacy privacyAnswer = this.getPrivacyWithListNames();
         String listName = privacyAnswer.getActiveName();
-        boolean isDefaultAndActive = privacyAnswer.getActiveName() != null
+        boolean isDefaultAndActive = listName != null && listName.equals(privacyAnswer.getDefaultName());
-                && privacyAnswer.getDefaultName() != null
-                && privacyAnswer.getActiveName().equals(
-                privacyAnswer.getDefaultName());
         return new PrivacyList(true, isDefaultAndActive, listName, getPrivacyListItems(listName));
     }
 
+    /**
+     * Get the name of the active list.
+     * 
+     * @return the name of the active list or null if there is none set.
+     * @throws NoResponseException
+     * @throws XMPPErrorException
+     * @throws NotConnectedException
+     * @since 4.1
+     */
+    public String getActiveListName() throws NoResponseException, XMPPErrorException, NotConnectedException {
+        if (cachedActiveListName != null) {
+            return cachedActiveListName;
+        }
+        return getPrivacyWithListNames().getActiveName();
+    }
+
     /**
      * Answer the default privacy list.
      * 
@@ -209,13 +305,47 @@ public class PrivacyListManager extends Manager {
     public PrivacyList getDefaultList() throws NoResponseException, XMPPErrorException, NotConnectedException {
         Privacy privacyAnswer = this.getPrivacyWithListNames();
         String listName = privacyAnswer.getDefaultName();
-        boolean isDefaultAndActive = privacyAnswer.getActiveName() != null
+        boolean isDefaultAndActive = listName != null && listName.equals(privacyAnswer.getActiveName());
-                && privacyAnswer.getDefaultName() != null
-                && privacyAnswer.getActiveName().equals(
-                privacyAnswer.getDefaultName());
         return new PrivacyList(isDefaultAndActive, true, listName, getPrivacyListItems(listName));
     }
 
+    /**
+     * Get the name of the default list.
+     *
+     * @return the name of the default list or null if there is none set.
+     * @throws NoResponseException
+     * @throws XMPPErrorException
+     * @throws NotConnectedException
+     * @since 4.1
+     */
+    public String getDefaultListName() throws NoResponseException, XMPPErrorException, NotConnectedException {
+        if (cachedDefaultListName != null) {
+            return cachedDefaultListName;
+        }
+        return getPrivacyWithListNames().getDefaultName();
+    }
+
+    /**
+     * Returns the name of the effective privacy list.
+     * <p>
+     * The effective privacy list is the one that is currently enforced on the connection. It's either the active
+     * privacy list, or, if the active privacy list is not set, the default privacy list.
+     * </p>
+     *
+     * @return the name of the effective privacy list or null if there is none set.
+     * @throws NoResponseException
+     * @throws XMPPErrorException
+     * @throws NotConnectedException
+     * @since 4.1
+     */
+    public String getEffectiveListName() throws NoResponseException, XMPPErrorException, NotConnectedException {
+        String activeListName = getActiveListName();
+        if (activeListName != null) {
+            return activeListName;
+        }
+        return getDefaultListName();
+    }
+
     /**
      * Answer the privacy list items under listName with the allowed and blocked permissions.
      * 

smack-extensions/src/main/java/org/jivesoftware/smackx/privacy/filter/SetActiveListFilter.java

@@ -0,0 +1,38 @@
+/**
+ *
+ * Copyright 2015 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.smackx.privacy.filter;
+
+import org.jivesoftware.smack.filter.FlexiblePacketTypeFilter;
+import org.jivesoftware.smack.packet.IQ.Type;
+import org.jivesoftware.smackx.privacy.packet.Privacy;
+
+public class SetActiveListFilter extends FlexiblePacketTypeFilter<Privacy> {
+
+    public static final SetActiveListFilter INSTANCE = new SetActiveListFilter();
+
+    private SetActiveListFilter() {
+    }
+
+    @Override
+    protected boolean acceptSpecific(Privacy privacy) {
+        if (privacy.getType() != Type.set) {
+            return false;
+        }
+        return privacy.getActiveName() != null || privacy.isDeclineActiveList();
+    }
+
+}

smack-extensions/src/main/java/org/jivesoftware/smackx/privacy/filter/SetDefaultListFilter.java

@@ -0,0 +1,38 @@
+/**
+ *
+ * Copyright 2015 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.smackx.privacy.filter;
+
+import org.jivesoftware.smack.filter.FlexiblePacketTypeFilter;
+import org.jivesoftware.smack.packet.IQ.Type;
+import org.jivesoftware.smackx.privacy.packet.Privacy;
+
+public class SetDefaultListFilter extends FlexiblePacketTypeFilter<Privacy> {
+
+    public static final SetDefaultListFilter INSTANCE = new SetDefaultListFilter();
+
+    private SetDefaultListFilter() {
+    }
+
+    @Override
+    protected boolean acceptSpecific(Privacy privacy) {
+        if (privacy.getType() != Type.set) {
+            return false;
+        }
+        return privacy.getDefaultName() != null || privacy.isDeclineDefaultList();
+    }
+
+}

smack-extensions/src/main/java/org/jivesoftware/smackx/privacy/packet/Privacy.java

@@ -292,7 +292,7 @@ public class Privacy extends IQ {
         	buf.append("<active/>");
         } else {
         	if (this.getActiveName() != null) {
-            	buf.append("<active name=\"").append(this.getActiveName()).append("\"/>");
+                buf.append("<active name=\"").escape(getActiveName()).append("\"/>");
             }
         }
         // Add the default tag
@@ -300,7 +300,7 @@ public class Privacy extends IQ {
         	buf.append("<default/>");
         } else {
 	        if (this.getDefaultName() != null) {
-	        	buf.append("<default name=\"").append(this.getDefaultName()).append("\"/>");
+                buf.append("<default name=\"").escape(getDefaultName()).append("\"/>");
 	        }
         }
         
@@ -310,9 +310,9 @@ public class Privacy extends IQ {
           List<PrivacyItem> items = entry.getValue();
 			// Begin the list tag
 			if (items.isEmpty()) {
-				buf.append("<list name=\"").append(listName).append("\"/>");
+                buf.append("<list name=\"").escape(listName).append("\"/>");
 			} else {
-				buf.append("<list name=\"").append(listName).append("\">");
+                buf.append("<list name=\"").escape(listName).append("\">");
 			}
 	        for (PrivacyItem item : items) {
 	        	// Append the item xml representation