iq.java

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package org.xmpp.packet;

import org.dom4j.Element;
import org.dom4j.QName;

import java.lang.reflect.Constructor;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

/**
 * 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 extended XML
 * namespace.
 */
public class IQ extends Packet {

    // Sequence and random number generator used for creating unique ID's.
    private static int sequence = 0;
    private static Random random = new Random();

    /**
     * Constructs a new IQ with an automatically generated ID and a type
     * of {@link Type#get IQ.Type.get}.
     */
    public IQ() {
        this.element = docFactory.createDocument().addElement("iq");
        String id = String.valueOf(random.nextInt(1000) + "-" + sequence++);
        setType(Type.get);
        setID(id);
    }

    /**
     * Constructs a new IQ using the specified type. A packet ID will
     * be automatically generated.
     *
     * @param type the IQ type.
     */
    public IQ(Type type) {
        this.element = docFactory.createDocument().addElement("iq");
        setType(type);
        String id = String.valueOf(random.nextInt(1000) + "-" + sequence++);
        setID(id);
    }

    /**
     * Constructs a new IQ using the specified type and ID.
     *
     * @param ID the packet ID of the IQ.
     * @param type the IQ type.
     */
    public IQ(Type type, String ID) {
        this.element = docFactory.createDocument().addElement("iq");
        setType(type);
        setID(ID);
    }

    /**
     * Constructs a new IQ using an existing Element. This is useful
     * for parsing incoming IQ Elements into IQ objects.
     *
     * @param element the IQ Element.
     */
    public IQ(Element element) {
        super(element);
    }

    /**
     * Constructs a new IQ using an existing Element. This is useful
     * for parsing incoming IQ Elements into IQ objects. Stringprep validation
     * on the TO address can be disabled. The FROM address will not be validated since the
     * server is the one that sets that value.
     *
     * @param element the IQ Element.
     * @param skipValidation true if stringprep should not be applied to the TO address.
     */
    public IQ(Element element, boolean skipValidation) {
        super(element, skipValidation);
    }

    /**
     * Constructs a new IQ that is a copy of an existing IQ.
     *
     * @param iq the iq packet.
     * @see #createCopy()
     */
    private IQ(IQ iq) {
        Element elementCopy = iq.element.createCopy();
        docFactory.createDocument().add(elementCopy);
        this.element = elementCopy;
        // Copy cached JIDs (for performance reasons)
        this.toJID = iq.toJID;
        this.fromJID = iq.fromJID;
    }

    /**
     * Returns the type of this IQ.
     *
     * @return the IQ type.
     * @see Type
     */
    public Type getType() {
        String type = element.attributeValue("type");
        if (type != null) {
            return Type.valueOf(type);
        }
        else {
            return null;
        }
    }

    /**
     * Sets the type of this IQ.
     *
     * @param type the IQ type.
     * @see Type
     */
    public void setType(Type type) {
        element.addAttribute("type", type==null?null:type.toString());
    }

    /**
     * Convenience routine to indicate if this is a request stanza. (get or set)
     *
     * @return True or false if this is a request stanza
     */
    public boolean isRequest() {
        Type type = getType();
        return (type != null && (type.equals(Type.get) || type.equals(Type.set)));
    }

    /**
     * Convenience routine to indicate if this is a response stanza. (result or error)
     *
     * @return True or false if this is a response stanza
     */
    public boolean isResponse() {
        Type type = getType();
        return (type != null && (type.equals(Type.result) || type.equals(Type.error)));
    }

    /**
     * Returns the child element of this IQ. IQ packets may have a single child
     * element in an extended namespace. This is a convenience method to
     * avoid manipulating the underlying packet's Element instance directly.<p>
     *
     * An IQ child element in extended namespaces is used to extend the features
     * of XMPP. Although any valid XML can be included in a child element
     * in an extended namespace, many common features have been standardized
     * as <a href="http://www.jabber.org/jeps">Jabber Enhancement Proposals</a>
     * (JEPs).
     *
     * @return the child element.
     */
    public Element getChildElement() {
        List elements = element.elements();
        if (elements.isEmpty()) {
            return null;
        }
        else {
            // Search for a child element that is in a different namespace.
            for (int i=0; i<elements.size(); i++) {
                Element element = (Element)elements.get(i);
                String namespace = element.getNamespaceURI();
                if (!namespace.equals("") && !namespace.equals("jabber:client") &&
                        !namespace.equals("jabber:server"))
                {
                    return element;
                }
            }
            return null;
        }
    }

    /**
     * Sets the child element of this IQ. IQ packets may have a single child
     * element in an extended namespace. This is a convenience method to
     * avoid manipulating this underlying packet's Element instance directly.<p>
     *
     * A sample use of this method might look like the following:
     * <pre>
     * IQ iq = new IQ("time_1");
     * iq.setTo("[e-mail]");
     * iq.setType(IQ.Type.GET);
     * iq.setChildElement(docFactory.createElement("query", "jabber:iq:time"));</pre><p>
     *
     * An IQ child element in extended namespaces is used to extend the features
     * of XMPP. Although any valid XML can be included in a child element
     * in an extended namespace, many common features have been standardized
     * as <a href="http://www.jabber.org/jeps">Jabber Enhancement Proposals</a>
     * (JEPs).
     *
     * @param childElement the child element.
     */
    public void setChildElement(Element childElement) {
        for (Iterator i=element.elementIterator(); i.hasNext(); ) {
            element.remove((Element)i.next());
        }
        element.add(childElement);