Smack/source/org/jivesoftware/smack/packet/IQ.java

/**
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 *
 * Copyright (C) 2002-2003 Jive Software. All rights reserved.
 * ====================================================================
 * The Jive Software License (based on Apache Software License, Version 1.1)
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    the documentation and/or other materials provided with the
 *    distribution.
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 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by
 *        Jive Software (http://www.jivesoftware.com)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Smack" and "Jive Software" must not be used to
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 * 5. Products derived from this software may not be called "Smack",
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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package org.jivesoftware.smack.packet;

/**
 * The base IQ (Info/Query) packet. IQ packets are used to get and set information
 * on the server, including authentication, roster operations, and creating
 * accounts. Each IQ packet has a specific type that indicates what type of action
 * is being taken: "get", "set", "result", or "error".<p>
 *
 * IQ packets can contain a single child element that exists in a specific XML
 * namespace. The combination of the element name and namespace determines what
 * type of IQ packet it is. Some example IQ subpacket snippets:<ul>
 *
 *  <li>&lt;query xmlns="jabber:iq:auth"&gt; -- an authentication IQ.
 *  <li>&lt;query xmlns="jabber:iq:private"&gt; -- a private storage IQ.
 *  <li>&lt;pubsub xmlns="http://jabber.org/protocol/pubsub"&gt; -- a pubsub IQ.
 * </ul>
 *
 * @author Matt Tucker
 */
public abstract class IQ extends Packet {

    private Type type = Type.GET;

    /**
     * Returns the type of the IQ packet.
     *
     * @return the type of the IQ packet.
     */
    public Type getType() {
        return type;
    }

    /**
     * Sets the type of the IQ packet.
     *
     * @param type the type of the IQ packet.
     */
    public void setType(Type type) {
        this.type = type;
    }

    public String toXML() {
        StringBuffer buf = new StringBuffer();
        buf.append("<iq ");
        if (getPacketID() != null) {
            buf.append("id=\"" + getPacketID() + "\" ");
        }
        if (getTo() != null) {
            buf.append("to=\"").append(getTo()).append("\" ");
        }
        if (getFrom() != null) {
            buf.append("from=\"").append(getFrom()).append("\" ");
        }
        if (type == null) {
            buf.append("type=\"get\">");
        }
        else {
            buf.append("type=\"").append(getType()).append("\">");
        }
        // Add the query section if there is one.
        String queryXML = 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>");
        return buf.toString();
    }

    /**
     * Returns the sub-element XML section of the IQ packet, or <tt>null</tt> if there
     * isn't one.<p>
     *
     * Generally, extensions of this class should override this method. This lets
     * the majority of IQ XML writing be generic, with each sub-class providing just
     * the packet-specific XML.
     *
     * @return the query section of the IQ XML.
     */
    public abstract String getChildElementXML();

    /**
     * A class to represent the type of the IQ packet. The types are:
     *
     * <ul>
     *      <li>IQ.Type.GET
     *      <li>IQ.Type.SET
     *      <li>IQ.Type.RESULT
     *      <li>IQ.Type.ERROR
     * </ul>
     */
    public static class Type {

        public static final Type GET = new Type("get");
        public static final Type SET = new Type("set");
        public static final Type RESULT = new Type("result");
        public static final Type ERROR = new Type("error");

        /**
         * Converts a String into the corresponding types. Valid String values
         * that can be converted to types are: "get", "set", "result", and "error".
         *
         * @param type the String value to covert.
         * @return the corresponding Type.
         */
        public static Type fromString(String type) {
            if (type == null) {
                return null;
            }
            type = type.toLowerCase();
            if (GET.toString().equals(type)) {
                return GET;
            }
            else if (SET.toString().equals(type)) {
                return SET;
            }
            else if (ERROR.toString().equals(type)) {
                return ERROR;
            }
            else if (RESULT.toString().equals(type)) {
                return RESULT;
            }
            else {
                return null;
            }
        }

        private String value;

        private Type(String value) {
            this.value = value;
        }

        public String toString() {
            return value;
        }
    }
}