Introduce AbstractStreamOpen and AbstractStreamClose

- Inherit StreamOpen and StreamClose from AbstractStream classes

smack-core/src/main/java/org/jivesoftware/smack/packet/AbstractStreamClose.java

@@ -0,0 +1,20 @@
+/**
+ *
+ * Copyright 2020 Aditya Borikar
+ *
+ * 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.packet;
+
+public abstract class AbstractStreamClose implements Nonza {
+}

smack-core/src/main/java/org/jivesoftware/smack/packet/AbstractStreamOpen.java

@@ -0,0 +1,79 @@
+/**
+ *
+ * Copyright 2020 Aditya Borikar
+ *
+ * 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.packet;
+
+import org.jivesoftware.smack.XMPPConnection;
+import org.jivesoftware.smack.packet.StreamOpen.StreamContentNamespace;
+import org.jivesoftware.smack.util.StringUtils;
+
+/**
+ * AbstractStreamOpen is actually a {@link TopLevelStreamElement}, however we
+ * implement {@link Nonza} here. This is because, {@link XMPPConnection} doesn't
+ * yet support sending {@link TopLevelStreamElement} directly and the same can only
+ * be achieved through {@link XMPPConnection#sendNonza(Nonza)}.
+ */
+public abstract class AbstractStreamOpen implements Nonza {
+    public static final String CLIENT_NAMESPACE = "jabber:client";
+    public static final String SERVER_NAMESPACE = "jabber:server";
+
+    /**
+     * RFC 6120 § 4.7.5.
+     */
+    public static final String VERSION = "1.0";
+
+    /**
+     * RFC 6120 § 4.7.1.
+     */
+    protected final String from;
+
+    /**
+     * RFC 6120 § 4.7.2.
+     */
+    protected final String to;
+
+    /**
+     * RFC 6120 § 4.7.3.
+     */
+    protected final String id;
+
+    /**
+     * RFC 6120 § 4.7.4.
+     */
+    protected final String lang;
+
+    /**
+     * RFC 6120 § 4.8.2.
+     */
+    protected final String contentNamespace;
+
+    public AbstractStreamOpen(CharSequence to, CharSequence from, String id, String lang, StreamContentNamespace ns) {
+        this.to = StringUtils.maybeToString(to);
+        this.from = StringUtils.maybeToString(from);
+        this.id = id;
+        this.lang = lang;
+        switch (ns) {
+        case client:
+            this.contentNamespace = CLIENT_NAMESPACE;
+            break;
+        case server:
+            this.contentNamespace = SERVER_NAMESPACE;
+            break;
+        default:
+            throw new IllegalStateException();
+        }
+    }
+}

smack-core/src/main/java/org/jivesoftware/smack/packet/StreamClose.java

@@ -16,7 +16,7 @@
  */
 package org.jivesoftware.smack.packet;
 
-public final class StreamClose implements Nonza {
+public final class StreamClose extends AbstractStreamClose {
 
     public static final StreamClose INSTANCE = new StreamClose();
 

smack-core/src/main/java/org/jivesoftware/smack/packet/StreamOpen.java

@@ -17,49 +17,14 @@
 
 package org.jivesoftware.smack.packet;
 
-import org.jivesoftware.smack.util.StringUtils;
 import org.jivesoftware.smack.util.XmlStringBuilder;
 
 /**
  * The stream open <b>tag</b>.
  */
-public class StreamOpen implements Nonza {
+public final class StreamOpen extends AbstractStreamOpen {
-
     public static final String ELEMENT = "stream:stream";
 
-    public static final String CLIENT_NAMESPACE = "jabber:client";
-    public static final String SERVER_NAMESPACE = "jabber:server";
-
-    /**
-     * RFC 6120 § 4.7.5.
-     */
-    public static final String VERSION = "1.0";
-
-    /**
-     * RFC 6120 § 4.7.1.
-     */
-    private final String from;
-
-    /**
-     * RFC 6120 § 4.7.2.
-     */
-    private final String to;
-
-    /**
-     * RFC 6120 § 4.7.3.
-     */
-    private final String id;
-
-    /**
-     * RFC 6120 § 4.7.4.
-     */
-    private final String lang;
-
-    /**
-     * RFC 6120 § 4.8.2.
-     */
-    private final String contentNamespace;
-
     public StreamOpen(CharSequence to) {
        this(to, null, null, null, StreamContentNamespace.client);
     }
@@ -69,20 +34,7 @@ public class StreamOpen implements Nonza {
     }
 
     public StreamOpen(CharSequence to, CharSequence from, String id, String lang, StreamContentNamespace ns) {
-        this.to = StringUtils.maybeToString(to);
+        super(to, from, id, lang, ns);
-        this.from = StringUtils.maybeToString(from);
-        this.id = id;
-        this.lang = lang;
-        switch (ns) {
-        case client:
-            this.contentNamespace = CLIENT_NAMESPACE;
-            break;
-        case server:
-            this.contentNamespace = SERVER_NAMESPACE;
-            break;
-        default:
-            throw new IllegalStateException();
-        }
     }
 
     @Override