src/org/jivesoftware/smack/packet/Packet.java - platform/external/smack - Git at Google

 /**
  * $RCSfile$
  * $Revision$
  * $Date$
  *
  * Copyright 2003-2007 Jive Software.
  *
  * All rights reserved. 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 java.io.ByteArrayOutputStream;
 import java.io.ObjectOutputStream;
 import java.io.Serializable;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.TimeZone;
 import java.util.concurrent.CopyOnWriteArrayList;

 import org.jivesoftware.smack.util.StringUtils;

 /**
  * Base class for XMPP packets. Every packet has a unique ID (which is automatically
  * generated, but can be overriden). Optionally, the "to" and "from" fields can be set,
  * as well as an arbitrary number of properties.
  *
  * Properties provide an easy mechanism for clients to share data. Each property has a
  * String name, and a value that is a Java primitive (int, long, float, double, boolean)
  * or any Serializable object (a Java object is Serializable when it implements the
  * Serializable interface).
  *
  * @author Matt Tucker
  */
 public abstract class Packet {

     protected static final String DEFAULT_LANGUAGE =
             java.util.Locale.getDefault().getLanguage().toLowerCase();

     private static String DEFAULT_XML_NS = null;

     /**
      * Constant used as packetID to indicate that a packet has no id. To indicate that a packet
      * has no id set this constant as the packet's id. When the packet is asked for its id the
      * answer will be <tt>null</tt>.
      */
     public static final String ID_NOT_AVAILABLE = "ID_NOT_AVAILABLE";

     /**
      * Date format as defined in XEP-0082 - XMPP Date and Time Profiles.
      * The time zone is set to UTC.
      * <p>
      * Date formats are not synchronized. Since multiple threads access the format concurrently,
      * it must be synchronized externally.
      */
     public static final DateFormat XEP_0082_UTC_FORMAT = new SimpleDateFormat(
                     "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
     static {
         XEP_0082_UTC_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
     }


     /**
      * A prefix helps to make sure that ID's are unique across mutliple instances.
      */
     private static String prefix = StringUtils.randomString(5) + "-";

     /**
      * Keeps track of the current increment, which is appended to the prefix to
      * forum a unique ID.
      */
     private static long id = 0;

     private String xmlns = DEFAULT_XML_NS;

     /**
      * Returns the next unique id. Each id made up of a short alphanumeric
      * prefix along with a unique numeric value.
      *
      * @return the next id.
      */
     public static synchronized String nextID() {
         return prefix + Long.toString(id++);
     }

     public static void setDefaultXmlns(String defaultXmlns) {
         DEFAULT_XML_NS = defaultXmlns;
     }

     private String packetID = null;
     private String to = null;
     private String from = null;
     private final List<PacketExtension> packetExtensions
             = new CopyOnWriteArrayList<PacketExtension>();

     private final Map<String,Object> properties = new HashMap<String, Object>();
     private XMPPError error = null;

     public Packet() {
     }

     public Packet(Packet p) {
         packetID = p.getPacketID();
         to = p.getTo();
         from = p.getFrom();
         xmlns = p.xmlns;
         error = p.error;

         // Copy extensions
         for (PacketExtension pe : p.getExtensions()) {
             addExtension(pe);
         }
     }

     /**
      * Returns the unique ID of the packet. The returned value could be <tt>null</tt> when
      * ID_NOT_AVAILABLE was set as the packet's id.
      *
      * @return the packet's unique ID or <tt>null</tt> if the packet's id is not available.
      */
     public String getPacketID() {
         if (ID_NOT_AVAILABLE.equals(packetID)) {
             return null;
         }

         if (packetID == null) {
             packetID = nextID();
         }
         return packetID;
     }

     /**
      * Sets the unique ID of the packet. To indicate that a packet has no id
      * pass the constant ID_NOT_AVAILABLE as the packet's id value.
      *
      * @param packetID the unique ID for the packet.
      */
     public void setPacketID(String packetID) {
         this.packetID = packetID;
     }

     /**
      * Returns who the packet is being sent "to", or <tt>null</tt> if
      * the value is not set. The XMPP protocol often makes the "to"
      * attribute optional, so it does not always need to be set.<p>
      *
      * The StringUtils class provides several useful methods for dealing with
      * XMPP addresses such as parsing the
      * {@link StringUtils#parseBareAddress(String) bare address},
      * {@link StringUtils#parseName(String) user name},
      * {@link StringUtils#parseServer(String) server}, and
      * {@link StringUtils#parseResource(String) resource}.
      *
      * @return who the packet is being sent to, or <tt>null</tt> if the
      *      value has not been set.
      */
     public String getTo() {
         return to;
     }

     /**
      * Sets who the packet is being sent "to". The XMPP protocol often makes
      * the "to" attribute optional, so it does not always need to be set.
      *
      * @param to who the packet is being sent to.
      */
     public void setTo(String to) {
         this.to = to;
     }

     /**
      * Returns who the packet is being sent "from" or <tt>null</tt> if
      * the value is not set. The XMPP protocol often makes the "from"
      * attribute optional, so it does not always need to be set.<p>
      *
      * The StringUtils class provides several useful methods for dealing with
      * XMPP addresses such as parsing the
      * {@link StringUtils#parseBareAddress(String) bare address},
      * {@link StringUtils#parseName(String) user name},
      * {@link StringUtils#parseServer(String) server}, and
      * {@link StringUtils#parseResource(String) resource}.
      *
      * @return who the packet is being sent from, or <tt>null</tt> if the
      *      value has not been set.
      */
     public String getFrom() {
         return from;
     }

     /**
      * Sets who the packet is being sent "from". The XMPP protocol often
      * makes the "from" attribute optional, so it does not always need to
      * be set.
      *
      * @param from who the packet is being sent to.
      */
     public void setFrom(String from) {
         this.from = from;
     }

     /**
      * Returns the error associated with this packet, or <tt>null</tt> if there are
      * no errors.
      *
      * @return the error sub-packet or <tt>null</tt> if there isn't an error.
      */
     public XMPPError getError() {
         return error;
     }

     /**
      * Sets the error for this packet.
      *
      * @param error the error to associate with this packet.
      */
     public void setError(XMPPError error) {
         this.error = error;
     }

     /**
      * Returns an unmodifiable collection of the packet extensions attached to the packet.
      *
      * @return the packet extensions.
      */
     public synchronized Collection<PacketExtension> getExtensions() {
         if (packetExtensions == null) {
             return Collections.emptyList();
         }
         return Collections.unmodifiableList(new ArrayList<PacketExtension>(packetExtensions));
     }

     /**
      * Returns the first extension of this packet that has the given namespace.
      *
      * @param namespace the namespace of the extension that is desired.
      * @return the packet extension with the given namespace.
      */
     public PacketExtension getExtension(String namespace) {
         return getExtension(null, namespace);
     }

     /**
      * Returns the first packet extension that matches the specified element name and
      * namespace, or <tt>null</tt> if it doesn't exist. If the provided elementName is null
      * than only the provided namespace is attempted to be matched. Packet extensions are
      * are arbitrary XML sub-documents in standard XMPP packets. By default, a
      * DefaultPacketExtension instance will be returned for each extension. However,
      * PacketExtensionProvider instances can be registered with the
      * {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager}
      * class to handle custom parsing. In that case, the type of the Object
      * will be determined by the provider.
      *
      * @param elementName the XML element name of the packet extension. (May be null)
      * @param namespace the XML element namespace of the packet extension.
      * @return the extension, or <tt>null</tt> if it doesn't exist.
      */
     public PacketExtension getExtension(String elementName, String namespace) {
         if (namespace == null) {
             return null;
         }
         for (PacketExtension ext : packetExtensions) {
             if ((elementName == null || elementName.equals(ext.getElementName()))
                     && namespace.equals(ext.getNamespace()))
             {
                 return ext;
             }
         }
         return null;
     }

     /**
      * Adds a packet extension to the packet. Does nothing if extension is null.
      *
      * @param extension a packet extension.
      */
     public void addExtension(PacketExtension extension) {
         if (extension == null) return;
         packetExtensions.add(extension);
     }

     /**
      * Adds a collection of packet extensions to the packet. Does nothing if extensions is null.
      *
      * @param extensions a collection of packet extensions
      */
     public void addExtensions(Collection<PacketExtension> extensions) {
         if (extensions == null) return;
         packetExtensions.addAll(extensions);
     }

     /**
      * Removes a packet extension from the packet.
      *
      * @param extension the packet extension to remove.
      */
     public void removeExtension(PacketExtension extension)  {
         packetExtensions.remove(extension);
     }

     /**
      * Returns the packet property with the specified name or <tt>null</tt> if the
      * property doesn't exist. Property values that were originally primitives will
      * be returned as their object equivalent. For example, an int property will be
      * returned as an Integer, a double as a Double, etc.
      *
      * @param name the name of the property.
      * @return the property, or <tt>null</tt> if the property doesn't exist.
      */
     public synchronized Object getProperty(String name) {
         if (properties == null) {
             return null;
         }
         return properties.get(name);
     }

     /**
      * Sets a property with an Object as the value. The value must be Serializable
      * or an IllegalArgumentException will be thrown.
      *
      * @param name the name of the property.
      * @param value the value of the property.
      */
     public synchronized void setProperty(String name, Object value) {
         if (!(value instanceof Serializable)) {
             throw new IllegalArgumentException("Value must be serialiazble");
         }
         properties.put(name, value);
     }

     /**
      * Deletes a property.
      *
      * @param name the name of the property to delete.
      */
     public synchronized void deleteProperty(String name) {
         if (properties == null) {
             return;
         }
         properties.remove(name);
     }

     /**
      * Returns an unmodifiable collection of all the property names that are set.
      *
      * @return all property names.
      */
     public synchronized Collection<String> getPropertyNames() {
         if (properties == null) {
             return Collections.emptySet();
         }
         return Collections.unmodifiableSet(new HashSet<String>(properties.keySet()));
     }

     /**
      * Returns the packet as XML. Every concrete extension of Packet must implement
      * this method. In addition to writing out packet-specific data, every sub-class
      * should also write out the error and the extensions data if they are defined.
      *
      * @return the XML format of the packet as a String.
      */
     public abstract String toXML();

     /**
      * Returns the extension sub-packets (including properties data) as an XML
      * String, or the Empty String if there are no packet extensions.
      *
      * @return the extension sub-packets as XML or the Empty String if there
      * are no packet extensions.
      */
     protected synchronized String getExtensionsXML() {
         StringBuilder buf = new StringBuilder();
         // Add in all standard extension sub-packets.
         for (PacketExtension extension : getExtensions()) {
             buf.append(extension.toXML());
         }
         // Add in packet properties.
         if (properties != null && !properties.isEmpty()) {
             buf.append("<properties xmlns=\"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>");
                 buf.append("<name>").append(StringUtils.escapeForXML(name)).append("</name>");
                 buf.append("<value type=\"");
                 if (value instanceof Integer) {
                     buf.append("integer\">").append(value).append("</value>");
                 }
                 else if (value instanceof Long) {
                     buf.append("long\">").append(value).append("</value>");
                 }
                 else if (value instanceof Float) {
                     buf.append("float\">").append(value).append("</value>");
                 }
                 else if (value instanceof Double) {
                     buf.append("double\">").append(value).append("</value>");
                 }
                 else if (value instanceof Boolean) {
                     buf.append("boolean\">").append(value).append("</value>");
                 }
                 else if (value instanceof String) {
                     buf.append("string\">");
                     buf.append(StringUtils.escapeForXML((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
                 // encode the binary data before adding it.
                 else {
                     ByteArrayOutputStream byteStream = null;
                     ObjectOutputStream out = null;
                     try {
                         byteStream = new ByteArrayOutputStream();
                         out = new ObjectOutputStream(byteStream);
                         out.writeObject(value);
                         buf.append("java-object\">");
                         String encodedVal = StringUtils.encodeBase64(byteStream.toByteArray());
                         buf.append(encodedVal).append("</value>");
                     }
                     catch (Exception e) {
                         e.printStackTrace();
                     }
                     finally {
                         if (out != null) {
                             try {
                                 out.close();
                             }
                             catch (Exception e) {
                                 // Ignore.
                             }
                         }
                         if (byteStream != null) {
                             try {
                                 byteStream.close();
                             }
                             catch (Exception e) {
                                 // Ignore.
                             }
                         }
                     }
                 }
                 buf.append("</property>");
             }
             buf.append("</properties>");
         }
         return buf.toString();
     }

     public String getXmlns() {
         return this.xmlns;
     }

     /**
      * Returns the default language used for all messages containing localized content.
      *
      * @return the default language
      */
     public static String getDefaultLanguage() {
         return DEFAULT_LANGUAGE;
     }

     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;

         Packet packet = (Packet) o;

         if (error != null ? !error.equals(packet.error) : packet.error != null) { return false; }
         if (from != null ? !from.equals(packet.from) : packet.from != null) { return false; }
         if (!packetExtensions.equals(packet.packetExtensions)) { return false; }
         if (packetID != null ? !packetID.equals(packet.packetID) : packet.packetID != null) {
             return false;
         }
         if (properties != null ? !properties.equals(packet.properties)
                 : packet.properties != null) {
             return false;
         }
         if (to != null ? !to.equals(packet.to) : packet.to != null)  { return false; }
         return !(xmlns != null ? !xmlns.equals(packet.xmlns) : packet.xmlns != null);
     }

     public int hashCode() {
         int result;
         result = (xmlns != null ? xmlns.hashCode() : 0);
         result = 31 * result + (packetID != null ? packetID.hashCode() : 0);
         result = 31 * result + (to != null ? to.hashCode() : 0);
         result = 31 * result + (from != null ? from.hashCode() : 0);
         result = 31 * result + packetExtensions.hashCode();
         result = 31 * result + properties.hashCode();
         result = 31 * result + (error != null ? error.hashCode() : 0);
         return result;
     }
 }
	/**
	* $RCSfile$
	* $Revision$
	* $Date$
	*
	* Copyright 2003-2007 Jive Software.
	*
	* All rights reserved. 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 java.io.ByteArrayOutputStream;
	import java.io.ObjectOutputStream;
	import java.io.Serializable;
	import java.text.DateFormat;
	import java.text.SimpleDateFormat;
	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.TimeZone;
	import java.util.concurrent.CopyOnWriteArrayList;

	import org.jivesoftware.smack.util.StringUtils;

	/**
	* Base class for XMPP packets. Every packet has a unique ID (which is automatically
	* generated, but can be overriden). Optionally, the "to" and "from" fields can be set,
	* as well as an arbitrary number of properties.
	*
	* Properties provide an easy mechanism for clients to share data. Each property has a
	* String name, and a value that is a Java primitive (int, long, float, double, boolean)
	* or any Serializable object (a Java object is Serializable when it implements the
	* Serializable interface).
	*
	* @author Matt Tucker
	*/
	public abstract class Packet {

	protected static final String DEFAULT_LANGUAGE =
	java.util.Locale.getDefault().getLanguage().toLowerCase();

	private static String DEFAULT_XML_NS = null;

	/**
	* Constant used as packetID to indicate that a packet has no id. To indicate that a packet
	* has no id set this constant as the packet's id. When the packet is asked for its id the
	* answer will be <tt>null</tt>.
	*/
	public static final String ID_NOT_AVAILABLE = "ID_NOT_AVAILABLE";

	/**
	* Date format as defined in XEP-0082 - XMPP Date and Time Profiles.
	* The time zone is set to UTC.
	* <p>
	* Date formats are not synchronized. Since multiple threads access the format concurrently,
	* it must be synchronized externally.
	*/
	public static final DateFormat XEP_0082_UTC_FORMAT = new SimpleDateFormat(
	"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
	static {
	XEP_0082_UTC_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
	}


	/**
	* A prefix helps to make sure that ID's are unique across mutliple instances.
	*/
	private static String prefix = StringUtils.randomString(5) + "-";

	/**
	* Keeps track of the current increment, which is appended to the prefix to
	* forum a unique ID.
	*/
	private static long id = 0;

	private String xmlns = DEFAULT_XML_NS;

	/**
	* Returns the next unique id. Each id made up of a short alphanumeric
	* prefix along with a unique numeric value.
	*
	* @return the next id.
	*/
	public static synchronized String nextID() {
	return prefix + Long.toString(id++);
	}

	public static void setDefaultXmlns(String defaultXmlns) {
	DEFAULT_XML_NS = defaultXmlns;
	}

	private String packetID = null;
	private String to = null;
	private String from = null;
	private final List<PacketExtension> packetExtensions
	= new CopyOnWriteArrayList<PacketExtension>();

	private final Map<String,Object> properties = new HashMap<String, Object>();
	private XMPPError error = null;

	public Packet() {
	}

	public Packet(Packet p) {
	packetID = p.getPacketID();
	to = p.getTo();
	from = p.getFrom();
	xmlns = p.xmlns;
	error = p.error;

	// Copy extensions
	for (PacketExtension pe : p.getExtensions()) {
	addExtension(pe);
	}
	}

	/**
	* Returns the unique ID of the packet. The returned value could be <tt>null</tt> when
	* ID_NOT_AVAILABLE was set as the packet's id.
	*
	* @return the packet's unique ID or <tt>null</tt> if the packet's id is not available.
	*/
	public String getPacketID() {
	if (ID_NOT_AVAILABLE.equals(packetID)) {
	return null;
	}

	if (packetID == null) {
	packetID = nextID();
	}
	return packetID;
	}

	/**
	* Sets the unique ID of the packet. To indicate that a packet has no id
	* pass the constant ID_NOT_AVAILABLE as the packet's id value.
	*
	* @param packetID the unique ID for the packet.
	*/
	public void setPacketID(String packetID) {
	this.packetID = packetID;
	}

	/**
	* Returns who the packet is being sent "to", or <tt>null</tt> if
	* the value is not set. The XMPP protocol often makes the "to"
	* attribute optional, so it does not always need to be set.<p>
	*
	* The StringUtils class provides several useful methods for dealing with
	* XMPP addresses such as parsing the
	* {@link StringUtils#parseBareAddress(String) bare address},
	* {@link StringUtils#parseName(String) user name},
	* {@link StringUtils#parseServer(String) server}, and
	* {@link StringUtils#parseResource(String) resource}.
	*
	* @return who the packet is being sent to, or <tt>null</tt> if the
	* value has not been set.
	*/
	public String getTo() {
	return to;
	}

	/**
	* Sets who the packet is being sent "to". The XMPP protocol often makes
	* the "to" attribute optional, so it does not always need to be set.
	*
	* @param to who the packet is being sent to.
	*/
	public void setTo(String to) {
	this.to = to;
	}

	/**
	* Returns who the packet is being sent "from" or <tt>null</tt> if
	* the value is not set. The XMPP protocol often makes the "from"
	* attribute optional, so it does not always need to be set.<p>
	*
	* The StringUtils class provides several useful methods for dealing with
	* XMPP addresses such as parsing the
	* {@link StringUtils#parseBareAddress(String) bare address},
	* {@link StringUtils#parseName(String) user name},
	* {@link StringUtils#parseServer(String) server}, and
	* {@link StringUtils#parseResource(String) resource}.
	*
	* @return who the packet is being sent from, or <tt>null</tt> if the
	* value has not been set.
	*/
	public String getFrom() {
	return from;
	}

	/**
	* Sets who the packet is being sent "from". The XMPP protocol often
	* makes the "from" attribute optional, so it does not always need to
	* be set.
	*
	* @param from who the packet is being sent to.
	*/
	public void setFrom(String from) {
	this.from = from;
	}

	/**
	* Returns the error associated with this packet, or <tt>null</tt> if there are
	* no errors.
	*
	* @return the error sub-packet or <tt>null</tt> if there isn't an error.
	*/
	public XMPPError getError() {
	return error;
	}

	/**
	* Sets the error for this packet.
	*
	* @param error the error to associate with this packet.
	*/
	public void setError(XMPPError error) {
	this.error = error;
	}

	/**
	* Returns an unmodifiable collection of the packet extensions attached to the packet.
	*
	* @return the packet extensions.
	*/
	public synchronized Collection<PacketExtension> getExtensions() {
	if (packetExtensions == null) {
	return Collections.emptyList();
	}
	return Collections.unmodifiableList(new ArrayList<PacketExtension>(packetExtensions));
	}

	/**
	* Returns the first extension of this packet that has the given namespace.
	*
	* @param namespace the namespace of the extension that is desired.
	* @return the packet extension with the given namespace.
	*/
	public PacketExtension getExtension(String namespace) {
	return getExtension(null, namespace);
	}

	/**
	* Returns the first packet extension that matches the specified element name and
	* namespace, or <tt>null</tt> if it doesn't exist. If the provided elementName is null
	* than only the provided namespace is attempted to be matched. Packet extensions are
	* are arbitrary XML sub-documents in standard XMPP packets. By default, a
	* DefaultPacketExtension instance will be returned for each extension. However,
	* PacketExtensionProvider instances can be registered with the
	* {@link org.jivesoftware.smack.provider.ProviderManager ProviderManager}
	* class to handle custom parsing. In that case, the type of the Object
	* will be determined by the provider.
	*
	* @param elementName the XML element name of the packet extension. (May be null)
	* @param namespace the XML element namespace of the packet extension.
	* @return the extension, or <tt>null</tt> if it doesn't exist.
	*/
	public PacketExtension getExtension(String elementName, String namespace) {
	if (namespace == null) {
	return null;
	}
	for (PacketExtension ext : packetExtensions) {
	if ((elementName == null \|\| elementName.equals(ext.getElementName()))
	&& namespace.equals(ext.getNamespace()))
	{
	return ext;
	}
	}
	return null;
	}

	/**
	* Adds a packet extension to the packet. Does nothing if extension is null.
	*
	* @param extension a packet extension.
	*/
	public void addExtension(PacketExtension extension) {
	if (extension == null) return;
	packetExtensions.add(extension);
	}

	/**
	* Adds a collection of packet extensions to the packet. Does nothing if extensions is null.
	*
	* @param extensions a collection of packet extensions
	*/
	public void addExtensions(Collection<PacketExtension> extensions) {
	if (extensions == null) return;
	packetExtensions.addAll(extensions);
	}

	/**
	* Removes a packet extension from the packet.
	*
	* @param extension the packet extension to remove.
	*/
	public void removeExtension(PacketExtension extension) {
	packetExtensions.remove(extension);
	}

	/**
	* Returns the packet property with the specified name or <tt>null</tt> if the
	* property doesn't exist. Property values that were originally primitives will
	* be returned as their object equivalent. For example, an int property will be
	* returned as an Integer, a double as a Double, etc.
	*
	* @param name the name of the property.
	* @return the property, or <tt>null</tt> if the property doesn't exist.
	*/
	public synchronized Object getProperty(String name) {
	if (properties == null) {
	return null;
	}
	return properties.get(name);
	}

	/**
	* Sets a property with an Object as the value. The value must be Serializable
	* or an IllegalArgumentException will be thrown.
	*
	* @param name the name of the property.
	* @param value the value of the property.
	*/
	public synchronized void setProperty(String name, Object value) {
	if (!(value instanceof Serializable)) {
	throw new IllegalArgumentException("Value must be serialiazble");
	}
	properties.put(name, value);
	}

	/**
	* Deletes a property.
	*
	* @param name the name of the property to delete.
	*/
	public synchronized void deleteProperty(String name) {
	if (properties == null) {
	return;
	}
	properties.remove(name);
	}

	/**
	* Returns an unmodifiable collection of all the property names that are set.
	*
	* @return all property names.
	*/
	public synchronized Collection<String> getPropertyNames() {
	if (properties == null) {
	return Collections.emptySet();
	}
	return Collections.unmodifiableSet(new HashSet<String>(properties.keySet()));
	}

	/**
	* Returns the packet as XML. Every concrete extension of Packet must implement
	* this method. In addition to writing out packet-specific data, every sub-class
	* should also write out the error and the extensions data if they are defined.
	*
	* @return the XML format of the packet as a String.
	*/
	public abstract String toXML();

	/**
	* Returns the extension sub-packets (including properties data) as an XML
	* String, or the Empty String if there are no packet extensions.
	*
	* @return the extension sub-packets as XML or the Empty String if there
	* are no packet extensions.
	*/
	protected synchronized String getExtensionsXML() {
	StringBuilder buf = new StringBuilder();
	// Add in all standard extension sub-packets.
	for (PacketExtension extension : getExtensions()) {
	buf.append(extension.toXML());
	}
	// Add in packet properties.
	if (properties != null && !properties.isEmpty()) {
	buf.append("<properties xmlns=\"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>");
	buf.append("<name>").append(StringUtils.escapeForXML(name)).append("</name>");
	buf.append("<value type=\"");
	if (value instanceof Integer) {
	buf.append("integer\">").append(value).append("</value>");
	}
	else if (value instanceof Long) {
	buf.append("long\">").append(value).append("</value>");
	}
	else if (value instanceof Float) {
	buf.append("float\">").append(value).append("</value>");
	}
	else if (value instanceof Double) {
	buf.append("double\">").append(value).append("</value>");
	}
	else if (value instanceof Boolean) {
	buf.append("boolean\">").append(value).append("</value>");
	}
	else if (value instanceof String) {
	buf.append("string\">");
	buf.append(StringUtils.escapeForXML((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
	// encode the binary data before adding it.
	else {
	ByteArrayOutputStream byteStream = null;
	ObjectOutputStream out = null;
	try {
	byteStream = new ByteArrayOutputStream();
	out = new ObjectOutputStream(byteStream);
	out.writeObject(value);
	buf.append("java-object\">");
	String encodedVal = StringUtils.encodeBase64(byteStream.toByteArray());
	buf.append(encodedVal).append("</value>");
	}
	catch (Exception e) {
	e.printStackTrace();
	}
	finally {
	if (out != null) {
	try {
	out.close();
	}
	catch (Exception e) {
	// Ignore.
	}
	}
	if (byteStream != null) {
	try {
	byteStream.close();
	}
	catch (Exception e) {
	// Ignore.
	}
	}
	}
	}
	buf.append("</property>");
	}
	buf.append("</properties>");
	}
	return buf.toString();
	}

	public String getXmlns() {
	return this.xmlns;
	}

	/**
	* Returns the default language used for all messages containing localized content.
	*
	* @return the default language
	*/
	public static String getDefaultLanguage() {
	return DEFAULT_LANGUAGE;
	}

	public boolean equals(Object o) {
	if (this == o) return true;
	if (o == null \|\| getClass() != o.getClass()) return false;

	Packet packet = (Packet) o;

	if (error != null ? !error.equals(packet.error) : packet.error != null) { return false; }
	if (from != null ? !from.equals(packet.from) : packet.from != null) { return false; }
	if (!packetExtensions.equals(packet.packetExtensions)) { return false; }
	if (packetID != null ? !packetID.equals(packet.packetID) : packet.packetID != null) {
	return false;
	}
	if (properties != null ? !properties.equals(packet.properties)
	: packet.properties != null) {
	return false;
	}
	if (to != null ? !to.equals(packet.to) : packet.to != null) { return false; }
	return !(xmlns != null ? !xmlns.equals(packet.xmlns) : packet.xmlns != null);
	}

	public int hashCode() {
	int result;
	result = (xmlns != null ? xmlns.hashCode() : 0);
	result = 31 * result + (packetID != null ? packetID.hashCode() : 0);
	result = 31 * result + (to != null ? to.hashCode() : 0);
	result = 31 * result + (from != null ? from.hashCode() : 0);
	result = 31 * result + packetExtensions.hashCode();
	result = 31 * result + properties.hashCode();
	result = 31 * result + (error != null ? error.hashCode() : 0);
	return result;
	}
	}