rawaggregate.java

pastry的java实现的2.0b版

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

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

- 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.

- Neither  the name  of Rice  University (RICE) nor  the names  of its
contributors may be  used to endorse or promote  products derived from
this software without specific prior written permission.

This software is provided by RICE and the contributors on an "as is"
basis, without any representations or warranties of any kind, express
or implied including, but not limited to, representations or
warranties of non-infringement, merchantability or fitness for a
particular purpose. In no event shall RICE or 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.

********************************************************************************/
package rice.p2p.aggregation.raw;

import rice.p2p.past.gc.GCPastContent;
import rice.p2p.past.*;
import rice.p2p.past.gc.*;
import rice.p2p.past.gc.rawserialization.*;
import rice.p2p.past.rawserialization.*;
import rice.p2p.util.rawserialization.SimpleOutputBuffer;
import rice.p2p.aggregation.*;
import rice.p2p.commonapi.*;
import rice.p2p.commonapi.rawserialization.*;
import rice.p2p.glacier.VersionKey;
import java.security.*;
import java.io.*;

/**
 * DESCRIBE THE CLASS
 *
 * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
 * @author jeffh
 */
public class RawAggregate extends Aggregate implements RawGCPastContent {

  private RawGCPastContent[] rawComponents;

  private final static long serialVersionUID = -4891386773008082L;
  /**
   * DESCRIBE THE FIELD
   */
  public final static short TYPE = 1;

  /**
   * Constructor for RawAggregate.
   *
   * @param components DESCRIBE THE PARAMETER
   * @param pointers DESCRIBE THE PARAMETER
   */
  public RawAggregate(GCPastContent[] components, Id[] pointers) {
    super(components, pointers);
    buildRawComponents(components);
    this.myId = null;
    this.pointers = pointers;
  }

  /**
   * Constructor for RawAggregate.
   *
   * @param components DESCRIBE THE PARAMETER
   * @param pointers DESCRIBE THE PARAMETER
   */
  public RawAggregate(RawGCPastContent[] components, Id[] pointers) {
    super(components, pointers);
    this.rawComponents = components;
    this.myId = null;
    this.pointers = pointers;
  }

  /**
   * Constructor for RawAggregate.
   *
   * @param buf DESCRIBE THE PARAMETER
   * @param endpoint DESCRIBE THE PARAMETER
   * @param contentDeserializer DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public RawAggregate(InputBuffer buf, Endpoint endpoint, PastContentDeserializer contentDeserializer) throws IOException {
    super(null, null);

    byte version = buf.readByte();
    switch (version) {
      case 0:
        myId = endpoint.readId(buf, buf.readShort());

        pointers = new Id[buf.readShort()];
        for (int i = 0; i < pointers.length; i++) {
          pointers[i] = endpoint.readId(buf, buf.readShort());
        }

        rawComponents = new RawGCPastContent[buf.readShort()];
        components = new GCPastContent[rawComponents.length];
        for (int i = 0; i < rawComponents.length; i++) {
          short type = buf.readShort();
          GCPastContent temp = (GCPastContent) contentDeserializer.deserializePastContent(buf, endpoint, type);
          if (type == 0) {
            components[i] = temp;
            rawComponents[i] = new JavaSerializedGCPastContent(temp);
          } else {
            components[i] = temp;
            rawComponents[i] = (RawGCPastContent) temp;
          }
        }
        break;
      default:
        throw new IOException("Unknown Version: " + version);
    }
  }

  /**
   * Gets the ContentHash attribute of the RawAggregate object
   *
   * @return The ContentHash value
   */
  public byte[] getContentHash() {
    byte[] bytes = null;
    int numBytes = 0;
    try {
//      ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
//      ObjectOutputStream objectStream = new ObjectOutputStream(byteStream);
//
//      objectStream.writeObject(components);
//      objectStream.writeObject(pointers);
//      objectStream.flush();
//
//      bytes = byteStream.toByteArray();
      SimpleOutputBuffer buf = new SimpleOutputBuffer();
      serializeHelper(buf);
      bytes = buf.getBytes();
      numBytes = buf.getWritten();
    } catch (IOException ioe) {
      return null;
    }

    MessageDigest md = null;
    try {
      md = MessageDigest.getInstance("SHA");
    } catch (NoSuchAlgorithmException e) {
      return null;
    }

    md.reset();
    md.update(bytes, 0, numBytes);

    return md.digest();
  }

  /**
   * Raw Serialization **************************************
   *
   * @return The Type value
   */
  public short getType() {
    return TYPE;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public int numComponents() {
    return rawComponents.length;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param buf DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   */
  public void serialize(OutputBuffer buf) throws IOException {
    buf.writeByte((byte) 0);
    // version
    buf.writeShort(myId.getType());
    myId.serialize(buf);
    serializeHelper(buf);
  }

  /**
   * Used in serialize() and getContentHash()
   *
   * @param buf
   * @throws IOException
   */
  private void serializeHelper(OutputBuffer buf) throws IOException {
    buf.writeShort((short) pointers.length);
    for (int i = 0; i < pointers.length; i++) {
      buf.writeShort(pointers[i].getType());
      pointers[i].serialize(buf);
    }

    buf.writeShort((short) rawComponents.length);
    for (int i = 0; i < rawComponents.length; i++) {
      buf.writeShort(rawComponents[i].getType());
      rawComponents[i].serialize(buf);
    }
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param in DESCRIBE THE PARAMETER
   * @exception IOException DESCRIBE THE EXCEPTION
   * @exception ClassNotFoundException DESCRIBE THE EXCEPTION
   */
  private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
    in.defaultReadObject();
    buildRawComponents(components);
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @param components DESCRIBE THE PARAMETER
   */
  private void buildRawComponents(GCPastContent[] components) {
    this.rawComponents = new RawGCPastContent[components.length];
    for (int i = 0; i < rawComponents.length; i++) {
      if (rawComponents[i] instanceof RawGCPastContent) {
        this.rawComponents[i] = (RawGCPastContent) components[i];
      } else {
        this.rawComponents[i] = new JavaSerializedGCPastContent(components[i]);
      }
    }
  }
}