pastryobjectinputstream.java

pastry的java实现的2.0b版

/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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********************************************************************************/
/*
 *  Created on May 10, 2004
 *
 *  To change the template for this generated file go to
 *  Window>Preferences>Java>Code Generation>Code and Comments
 */
package rice.pastry.messaging;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;

import rice.pastry.*;

/**
 * coalesces NodeHandles on the fly during java deserialization
 *
 * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
 * @author Jeff Hoye
 */
public class PastryObjectInputStream extends ObjectInputStream {

  /**
   * DESCRIBE THE FIELD
   */
  protected PastryNode node;

  /**
   * @param stream DESCRIBE THE PARAMETER
   * @param node DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   * @throws java.io.IOException
   */
  public PastryObjectInputStream(InputStream stream, PastryNode node)
     throws IOException {
    super(stream);
    this.node = node;
    enableResolveObject(true);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param input DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  protected Object resolveObject(Object input) throws IOException {
    if (input instanceof NodeHandle) {
//      System.out.println("POIS.resolveObject("+input+"@"+System.identityHashCode(input)+"):"+node);
      if (node != null) {
        // coalesce
        input = node.coalesce((NodeHandle) input);
      }
    }

    return input;
  }
}