wireheader.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 *
 * $Id: WireHeader.java,v 1.13 2005/11/22 22:04:01 hamada Exp $
 *
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * 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.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA"
 *    must not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 */


package net.jxta.impl.pipe;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import net.jxta.document.Attributable;
import net.jxta.document.Attribute;
import net.jxta.document.Document;
import net.jxta.document.Element;
import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredDocumentFactory;
import net.jxta.document.StructuredTextDocument;
import net.jxta.document.XMLElement;
import net.jxta.id.ID;
import net.jxta.id.IDFactory;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * This class implements a JXTA-WIRE header.
 */
public class WireHeader {

    private final static Logger LOG = Logger.getLogger(WireHeader.class.getName());

    public static final String Name = "JxtaWire";
    public static final String MsgIdTag = "MsgId";
    public static final String PipeIdTag = "PipeId";
    public static final String SrcTag = "SrcPeer";
    public static final String TTLTag = "TTL";
    public static final String PeerTag = "VisitedPeer";

    private ID srcPeer = ID.nullID;
    private ID pipeID = ID.nullID;
    private String msgId = null;
    private int    TTL = Integer.MIN_VALUE;

    private Set peers = new HashSet();

    public WireHeader() {}

    public WireHeader(ID srcPeer, ID wireId, int ttl) {

        this.srcPeer = srcPeer;
        this.pipeID = wireId;
        this.TTL = ttl;
    }

    public WireHeader(Element root) {
        this();
        initialize(root);
    }

    public void setSrcPeer(ID p) {
        srcPeer = p;
    }

    public ID getSrcPeer() {
        return srcPeer;
    }

    public void setTTL(int t) {
        TTL = t;
    }

    public int getTTL() {
        return TTL;
    }

    public void addPeer(String peer) {
        peers.add(peer);
    }

    public void setPeers(Set v) {
        peers = new HashSet(v);
    }

    public boolean containsPeer(String peer) {
        return peers.contains(peer);
    }

    public String[] getPeers() {
        return (String[]) peers.toArray(new String[0]);
    }

    public String getMsgId() {
        return msgId;
    }

    public void setMsgId(String id) {
        this.msgId = id;
    }

    public ID getPipeID() {
        return pipeID;
    }

    public void setPipeID(ID id) {
        this.pipeID = id;
    }

    /**
     *  Called to handle elements during parsing.
     *
     *  @param elem Element to parse
     *  @return true if element was handled, otherwise false.
     */
    protected boolean handleElement(XMLElement elem) {

        if (elem.getName().equals(SrcTag)) {
            try {
                URI pID = new URI(elem.getTextValue());
                setSrcPeer(IDFactory.fromURI(pID));
            } catch (URISyntaxException badID) {
                throw new IllegalArgumentException("Bad PeerID ID in header: " + elem.getTextValue());
            }
            return true;
        }

        if (elem.getName().equals(MsgIdTag)) {
            msgId = elem.getTextValue();
            return true;
        }

        if (elem.getName().equals(PipeIdTag)) {
            try {
                URI pipeID = new URI(elem.getTextValue());
                setPipeID(IDFactory.fromURI(pipeID));
            } catch (URISyntaxException badID) {
                throw new IllegalArgumentException("Bad pipe ID in header");
            }

            return true;
        }

        if (elem.getName().equals(TTLTag)) {
            TTL = Integer.parseInt(elem.getTextValue());
            return true;
        }
        if (elem.getName().equals(PeerTag)) {
            //ignoring obsolete tag
            return true;
        }

        return false;
    }

    /**
     *  internal method to process a document into a header.
     *
     *  @param root where to start.
     */
    protected void initialize(Element root) {
        if(!XMLElement.class.isInstance(root)) {
            throw new IllegalArgumentException(getClass().getName() + " only supports XLMElement");
        }

        XMLElement doc = (XMLElement) root;

        String doctype = doc.getName();

        String typedoctype = "";
        Attribute itsType = doc.getAttribute("type");
        if(null != itsType) {
            typedoctype = itsType.getValue();
        }

        if(!doctype.equals(Name) && !Name.equals(typedoctype)) {
            throw new IllegalArgumentException("Could not construct : "
                                                + getClass().getName() + "from doc containing a " + doc.getName());
        }

        Enumeration elements = doc.getChildren();

        while (elements.hasMoreElements()) {
            XMLElement elem = (XMLElement) elements.nextElement();

            if(!handleElement(elem)) {
                if (LOG.isEnabledFor(Level.DEBUG)) {
                    LOG.debug("Unhandled Element: " + elem.getName());
                }
            }
        }

        // Sanity Check!

        if(null == getMsgId()) {
            throw new IllegalArgumentException("Header does not contain a message id");
        }

        if(ID.nullID == getPipeID()) {
            throw new IllegalArgumentException("Header does not contain a pipe id");
        }
    }

    /**
     *  {@inheritDoc}
     */
    public Document getDocument(MimeMediaType encodeAs) {
        StructuredTextDocument doc = (StructuredTextDocument)
                                     StructuredDocumentFactory.newStructuredDocument(
                                         encodeAs, Name);

        if(doc instanceof Attributable) {
            ((Attributable)doc).addAttribute("xmlns:jxta", "http://jxta.org");
        }

        if(null == getMsgId()) {
            throw new IllegalStateException("Message id is not initialized");
        }

        if(ID.nullID == getPipeID()) {
            throw new IllegalStateException("PipeID is not initialized");
        }

        Element e = null;

        if ((srcPeer != null) && (srcPeer != ID.nullID)) {
            e = doc.createElement(SrcTag, srcPeer.toString());
            doc.appendChild(e);
        }

        e = doc.createElement(PipeIdTag, getPipeID().toString());
        doc.appendChild(e);

        e = doc.createElement(MsgIdTag, getMsgId());
        doc.appendChild(e);

        e = doc.createElement(TTLTag, Integer.toString(TTL));
        doc.appendChild(e);

        Iterator eachPeer = peers.iterator();

        return doc;
    }
}