piperesolvermsg.java

JXTA源文件

/*
 * Copyright (c) 2002 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.
 *
 * $Id: PipeResolverMsg.java,v 1.11 2004/10/09 23:35:38 bondolo Exp $
 */

package net.jxta.impl.protocol;

import java.io.InputStream;
import java.io.StringWriter;
import java.io.StringReader;
import java.io.Writer;
import java.net.URI;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Set;

import java.io.IOException;
import java.net.URISyntaxException;

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

import net.jxta.document.AdvertisementFactory;
import net.jxta.document.Attribute;
import net.jxta.document.Attributable;
import net.jxta.document.Element;
import net.jxta.document.TextElement;
import net.jxta.document.MimeMediaType;
import net.jxta.document.Document;
import net.jxta.document.StructuredTextDocument;
import net.jxta.document.StructuredDocumentFactory;
import net.jxta.document.StructuredDocumentUtils;
import net.jxta.id.ID;
import net.jxta.id.IDFactory;
import net.jxta.peer.PeerID;
import net.jxta.pipe.PipeID;
import net.jxta.protocol.PeerAdvertisement;
import net.jxta.protocol.PipeResolverMessage;

/**
 * This class implements {@link net.jxta.protocol.PipeResolverMessage} by
 * providing {@link #initialize(Element)} and {@link #getDocument(MimeMediaType)}
 * implementations.
 *
 * <p/>It implements the PipeResolver message for the standard Pipe
   Binding Protocol (PBP) with the following schema:
 *
 * <pre><code>
 * &lt;xs:element name="jxta:PipeResolver" type="jxta:PipeResolver"/>
 *
 * &lt;xs:simpleType name="PipeResolverMsgType">
 *   &lt;xs:restriction base="xs:string">
 *     &lt;!-- QUERY -->
 *     &lt;xs:enumeration value="Query"/>
 *     &lt;!-- ANSWER -->
 *     &lt;xs:enumeration value="Answer"/>
 *   &lt;/xs:restriction>
 * &lt;/xs:simpleType>
 *
 * &lt;xs:complexType name="PipeResolver">
 *   &lt;xs:sequence>
 *     &lt;xs:element name="MsgType" type="jxta:PipeResolverMsgType"/>
 *     &lt;xs:element name="PipeId" type="jxta:JXTAID"/>
 * &lt;xs:element name="Type" type="xs:string"/>
 *
 *     &lt;!-- used in the query -->
 * &lt;xs:element name="Cached" type="xs:boolean" default="true" minOccurs="0"/>
 *     &lt;xs:element name="Peer" type="jxta:JXTAID" minOccurs="0"/>
 *
 *     &lt;!-- used in the answer -->
 *     &lt;xs:element name="Found" type="xs:boolean"/>
 * &lt;!-- This should refer to a peer adv, but is instead a whole doc -->
 * &lt;xs:element name="PeerAdv" type="xs:string" minOccurs="0"/>
 *   &lt;/xs:sequence>
 * &lt;/xs:complexType>
 * </code></pre>
 *
 * @see net.jxta.pipe.PipeService
 * @see net.jxta.impl.pipe.PipeServiceImpl
 * @see <a href="http://spec.jxta.org/nonav/v1.0/docbook/JXTAProtocols.html#proto-pbp" target="_blank">JXTA Protocols Specification : Pipe Binding Protocol</a>
 **/
public class PipeResolverMsg extends PipeResolverMessage {
    
    /**
     *  Log4J Logger
     **/
    private final static transient Logger LOG = Logger.getLogger( PipeResolverMsg.class.getName());
    
    private final static String MsgTypeTag       = "MsgType";
    private final static String PipeIdTag        = "PipeId";
    private final static String PipeTypeTag      = "Type";
    private final static String PeerIdTag        = "Peer";
    private final static String PeerAdvTag       = "PeerAdv";
    private final static String FoundTag         = "Found";
    
    private final static String QueryMsgType     = "Query";
    private final static String AnswerMsgType    = "Answer";
    
    public PipeResolverMsg() {
        super();
    }
    
    public PipeResolverMsg(Element root) {
        this();
        initialize( root );
    }
    
    /**
     *  Initializes the message from a document.
     **/
    protected void initialize(Element root) {
        if( !TextElement.class.isInstance( root ) )
            throw new IllegalArgumentException( getClass().getName() + " only supports TextElement" );
        
        TextElement doc = (TextElement) root;
        
        String docName = doc.getName();
        
        if( !docName.equals(getMessageType()) )
            throw new IllegalArgumentException( "Could not construct : "
            + getClass().getName()
            + "from doc containing a "
            + docName );
        
        Enumeration each = doc.getChildren();
        
        while (each.hasMoreElements()) {
            TextElement elem = (TextElement) each.nextElement();
            
            if (elem.getName().equals(MsgTypeTag)) {
                String msgtype = elem.getTextValue();
                if( msgtype.equals( QueryMsgType ) )
                    setMsgType( PipeResolverMessage.MessageType.QUERY );
                else if ( msgtype.equals( AnswerMsgType ) )
                    setMsgType( PipeResolverMessage.MessageType.ANSWER );
                else
                    throw new IllegalArgumentException( "Unexpected Message Type in parsing." );
                continue;
            }
            
            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 message" );
                }
                continue;
            }
            
            if (elem.getName().equals(PipeTypeTag)) {
                setPipeType( elem.getTextValue() );
                continue;
            }
            
            if (elem.getName().equals(PeerIdTag)) {
                try {
                    URI peerID =  new URI( elem.getTextValue() );
                    addPeerID( IDFactory.fromURI( peerID ) );
                } catch ( URISyntaxException badID ) {
                    throw new IllegalArgumentException( "Bad peer ID in message" );
                }
                continue;
            }
            
            if (elem.getName().equals(FoundTag)) {
                setFound( Boolean.valueOf(elem.getTextValue()).booleanValue() );
                continue;
            }
            
            // let's check whether the responder sent us a adv
            if (elem.getName().equals(PeerAdvTag)) {
                String peerAdv = elem.getTextValue();
                try {
                    setInputPeerAdv( (PeerAdvertisement) AdvertisementFactory.newAdvertisement(
                    MimeMediaType.XMLUTF8,
                    new StringReader(peerAdv)) );
                } catch ( IOException caught ) {
                    if (LOG.isEnabledFor(Level.DEBUG))
                        LOG.debug( "Malformed peer adv in message", caught );
                    throw new IllegalArgumentException( "Malformed peer adv in message : " + caught.getMessage() );
                }
                continue;
            }

        }
        
        // Begin checking sanity!
        PipeResolverMessage.MessageType msgType = getMsgType();
        if ( null == msgType )
            throw new IllegalArgumentException( "Message type was never set!" );
        
        ID pipeID = getPipeID();
        if( (null == pipeID) || ID.nullID.equals(pipeID) || !(pipeID instanceof PipeID) )
            throw new IllegalArgumentException( "Input Pipe ID not set or invalid" );
        
        if ( null == getPipeType() )
            throw new IllegalArgumentException( "Pipe type was never set!" );
        
        //Query extra checks
        
        //Response extra checks
        if (  PipeResolverMessage.MessageType.ANSWER.equals( msgType ) ) {
            if( getPeerIDs().isEmpty() ) {
                throw new IllegalArgumentException( "An answer without responses is invalid" );
            }
        }
    }
    
    /**
     *  Creates a document out of the message.
     *
     *  @param  encodeAs  The document representation format requested.
     *  @return the message as a document.
     **/
    public Document getDocument(MimeMediaType encodeAs) {
        StructuredTextDocument doc = (StructuredTextDocument)
        StructuredDocumentFactory.newStructuredDocument(encodeAs, getMessageType() );
        
        if( doc instanceof Attributable ) {
            ((Attributable)doc).addAttribute( "xmlns:jxta", "http://jxta.org" );
        }
        
        PipeResolverMessage.MessageType msgType = getMsgType();
        if ( null == msgType ) {
            throw new IllegalStateException( "Message type was never set!" );
        }
        
        ID pipeID = getPipeID();
        if( (null == pipeID) || ID.nullID.equals(pipeID) || !(pipeID instanceof PipeID) ) {
            throw new IllegalStateException( "Pipe ID not set or invalid." );
        }
        
        String pipeType = getPipeType();
        if ( (null == pipeType) || (0 == pipeType.trim().length()) ) {
            throw new IllegalStateException( "Pipe type was never set or is invalid." );
        }
        
        Element e = null;
        if(  PipeResolverMessage.MessageType.QUERY.equals( msgType ) ) {
            e = doc.createElement(MsgTypeTag, QueryMsgType);
        } else if (  PipeResolverMessage.MessageType.ANSWER.equals( msgType ) ) {
            e = doc.createElement(MsgTypeTag, AnswerMsgType);
        } else {
            throw new IllegalStateException( "Unknown message type :" + msgType.toString() );
        }
        doc.appendChild(e);
        
        e = doc.createElement(PipeIdTag, pipeID.toString() );
        doc.appendChild(e);
        
        if( (null != pipeType) && (0 != pipeType.length()) ) {
            e = doc.createElement( PipeTypeTag, pipeType );
            doc.appendChild(e);
        }
        
        // Write the peer ids.
        Set peers = getPeerIDs();
        
        if ( PipeResolverMessage.MessageType.ANSWER.equals( msgType ) && peers.isEmpty() ) {
            throw new IllegalStateException( "An ANSWER message must contain at least one peer as part of the response." );
        }
        
        Iterator eachPeer = peers.iterator();
        
        while( eachPeer.hasNext() ) {
            ID aPeer = (ID) eachPeer.next();
            
                e = doc.createElement(PeerIdTag, aPeer.toString() );
                doc.appendChild(e);
        }
        
        if(  PipeResolverMessage.MessageType.QUERY.equals( msgType ) ) {
            // nothing for now...
        } else if (  PipeResolverMessage.MessageType.ANSWER.equals( msgType ) ) {
            e = doc.createElement(FoundTag, (isFound() ? Boolean.TRUE : Boolean.FALSE).toString() );
            doc.appendChild(e);
            
            PeerAdvertisement peerAdv = getInputPeerAdv();

            if (peerAdv != null) {
                if( !peers.contains( peerAdv.getPeerID() ) ) {
                    throw new IllegalStateException( "Provided Peer Advertisement does not refer to one of the peers in the response list." );
                }
                
		    StructuredTextDocument asDoc = (StructuredTextDocument)
			peerAdv.getDocument( MimeMediaType.XMLUTF8 );
                
                e = doc.createElement( PeerAdvTag, asDoc.toString() );
		    doc.appendChild(e);
	    }
        } else {
            throw new IllegalStateException( "Unknown message type :" + msgType.toString() );
        }
        
        return doc;
    }
}