visitorcredential.java

Java p2p程序设计2002年版

/*
 * VisitorCredential.java
 *
 * Created on September 24, 2001, 8:05 PM
 */

package com.sams.jxta.groups;
import net.jxta.peergroup.*;
import net.jxta.protocol.*;
import net.jxta.service.*;
import net.jxta.exception.*;
import net.jxta.membership.*;
import net.jxta.peer.*;
import net.jxta.document.*;
import net.jxta.credential.*;
import java.util.*;
import java.net.URL;
import net.jxta.id.IDFactory;
import net.jxta.id.ID;
/**
 * Credentials are sent with every message to ensure that the
 * message sender is a valid member of the group. This means we
 * have to be careful about how much information is in the credential.
 * We also have to be careful that we don't take too much time
 * verifying the credential each time a message is received.
 *
 * This XML message is outbound and intended fo consumers of messages from this
 * peer.
 */

public class VisitorCredential implements Credential {
   
   protected VisitorMembership source;
   
   protected ID peerID;
   
   protected PeerGroup peerGroup;
   protected ID peerGroupID;
   
   // Specific Information
   protected boolean debugMode;
   protected String visitorName;
   
   protected VisitorCredential( VisitorMembership source) {
      System.out.println(this.getClass().getName()+" **** VisitorCredential()");
      this.source = (VisitorMembership) source;
      peerID = source.getPeerGroup().getPeerID();
      peerGroup = source.getPeerGroup();
      
   }
   protected VisitorCredential( VisitorMembership source, VisitorAuthenticator visitor ) {
      System.out.println(this.getClass().getName()+" **** VisitorCredential()");
      this.source = (VisitorMembership) source;
      peerID = source.getPeerGroup().getPeerID();
      peerGroup = source.getPeerGroup();
      // Specific information
      debugMode = visitor.getDebugMode();
      visitorName = visitor.getVisitorName();
      
   }
   /**
    * Welcome to the uglyness of JXTA!
    *
    * Credentials are created by an Authenticator. This means that
    * the Authenticator will probably own or create the credentials
    * based on either a self discovery, user input, or both. Given
    * that expectation, we pass in our authenticator object to be
    * digested.
    */
   protected VisitorCredential( VisitorMembership source, PeerGroupID peergroupID, PeerID peerID, VisitorAuthenticator visitor ) throws PeerGroupException {
      System.out.println(this.getClass().getName()+" **** VisitorCredential()");
      peerGroup = source.getPeerGroup();
      this.source = (VisitorMembership) source;
      // Verify that the source group and ID match.
      if( !source.getPeerGroup().getPeerGroupID().equals( peerGroupID ) ){
         throw new PeerGroupException( "Cannot credential for a different peer group." );
      }
      this.peerID = peerID;
      
      // Specific information
      debugMode = visitor.getDebugMode();
      visitorName = visitor.getVisitorName();
   }
   
   /**
    * Returns the service which generated this credential.
    */
   public net.jxta.membership.MembershipService getSourceService() {
      return source;
   }
   /**
    * Returns the peer group ID
    */
   public ID getPeerGroupID() {
      return source.getPeerGroup().getPeerGroupID();
   }
   /**
    * Returns the peer ID. This is the peer that was
    * authenticated. Messages with this ID came
    * from the peer that created this credential.
    */
   
   public ID getPeerID() {
      return peerID;
   }
    /**
    * Returns the document representation of this credential.
    * The document can be saved as local proof of the credential.
    */
   public StructuredDocument getDocument(MimeMediaType as) throws Exception {
      StructuredDocument doc = StructuredDocumentFactory.newStructuredDocument( as, "VisitorCredential" );
      peerGroup.getPeerGroupID();
      Element e = doc.createElement( "PeerGroupID", peerGroup.getPeerGroupID().toString() );
      doc.appendChild( e );
      
      e = doc.createElement( "PeerID", peerID.toString() );
      doc.appendChild( e );
      
      /**
       * The following are items that we asked the visitor to provide.
       * Limit this information to avoid cloging the network.
       */
      
      e = doc.createElement( "VisitorName",  visitorName);
      doc.appendChild( e );
      
      e = doc.createElement( "DebugMode",  ""+debugMode);
      doc.appendChild( e );
      
      return doc;
   }
   /**
    * This constructs a credential from an XML element.
    */
   protected VisitorCredential(VisitorMembership source, Element element) throws PeerGroupException, Exception {
      System.out.println(this.getClass().getName()+" **** VisitorCredential()");
      this.source = source;
      this.peerGroup = source.getPeerGroup();
      
      if( !"VisitorCredential".equals(element.getKey()) ){
         throw new PeerGroupException( "Element does not contain a recognized credential format" );
      }
      
      Enumeration children = element.getChildren( "PeerGroupID" );
      if( !children.hasMoreElements() ){
         throw new RuntimeException( "Missing PeerGroupID Element" );
      }
      peerGroupID = (PeerGroupID) IDFactory.fromURL( new URL( (String) ((Element) children.nextElement()).getValue() ) );
      
      //if( children.hasMoreElements() ){
      //   throw new RuntimeException( "Extra PeerGroupID Elements" );
      //}
      
      children = element.getChildren( "PeerID" );
      if( !children.hasMoreElements() ){
         throw new RuntimeException( "Missing PeerID Element" );
      }
      peerID = (PeerID) IDFactory.fromURL( new URL( (String) ((Element) children.nextElement()).getValue() ) );
      
      // Verify that the source group and ID match.
      if( !source.getPeerGroup().getPeerGroupID().equals( peerGroupID ) ){
         throw new PeerGroupException( "Cannot credential for a different peer group." );
      }
      
      //if( children.hasMoreElements() ){ ??? Don't know why this is here
      //   throw new RuntimeException( "Extra PeerID Elements" );
      //}
      
      //children = element.getChildren( "PeerID" );
      //if( !children.hasMoreElements() ){
      //   throw new RuntimeException( "Missing PeerID Element" );
      //}
      
      //=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-//
      // The following are items that we asked the visitor to provide //
      //=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-//
      
      children = element.getChildren( "VistorName" );
      String visitor = (String) ((Element) children.nextElement()).getValue();
      if( children.hasMoreElements() ){
         throw new RuntimeException( "VistorName Element Not Found" );
      }
      
      children = element.getChildren( "DebugMode" );
      debugMode = Boolean.getBoolean( (String) ((Element) children.nextElement()).getValue() );
      if( children.hasMoreElements() ){
         throw new RuntimeException( "DebugMode Element Not Found" );
      }
      
   }
   
        /* From here on are the methods specific to this credential type */
   
   public String getIdentity() {
      return visitorName;
   }
   
   
}// end of VisitorCredentials