1 /*
2 * $Id: IdempotentSecureHashReceiver.java 8952 2007-10-05 23:11:13Z holger $
3 * --------------------------------------------------------------------------------------
4 * Copyright (c) MuleSource, Inc. All rights reserved. http://www.mulesource.com
5 *
6 * The software in this package is published under the terms of the CPAL v1.0
7 * license, a copy of which has been included with this distribution in the
8 * LICENSE.txt file.
9 */
10
11 package org.mule.routing.inbound;
12
13 import org.mule.transformers.simple.ByteArrayToHexString;
14 import org.mule.transformers.simple.SerializableToByteArray;
15 import org.mule.umo.MessagingException;
16 import org.mule.umo.UMOEvent;
17 import org.mule.umo.routing.RoutingException;
18 import org.mule.umo.transformer.TransformerException;
19
20 import java.security.MessageDigest;
21 import java.security.NoSuchAlgorithmException;
22
23 /**
24 * <code>IdempotentSecureHashReceiver</code> ensures that only unique messages are
25 * received by a component. It does this by calculating the SHA-256 hash of the message
26 * itself. This provides a value with an infinitesimally small chance of a collision. This
27 * can be used to filter message duplicates. Please keep in mind that the hash is
28 * calculated over the entire byte array representing the message, so any leading or
29 * trailing spaces or extraneous bytes (like padding) can produce different hash values
30 * for the same semantic message content. Care should be taken to ensure that messages do
31 * not contain extraneous bytes. This class is useful when the message does not support
32 * unique identifiers.
33 */
34
35 public class IdempotentSecureHashReceiver extends IdempotentReceiver
36 {
37 private static final String messageDigestAlgorithm = "SHA-256";
38
39 private final SerializableToByteArray objectToByteArray = new SerializableToByteArray();
40 private final ByteArrayToHexString byteArrayToHexString = new ByteArrayToHexString();
41
42 // @Override
43 protected Object getIdForEvent(UMOEvent event) throws MessagingException
44 {
45 try
46 {
47 MessageDigest md = MessageDigest.getInstance(messageDigestAlgorithm);
48 return byteArrayToHexString.transform(md.digest((byte[]) objectToByteArray.transform(event.getMessage()
49 .getPayload())));
50 }
51 catch (NoSuchAlgorithmException nsa)
52 {
53 throw new RoutingException(event.getMessage(), event.getEndpoint(), nsa);
54 }
55 catch (TransformerException te)
56 {
57 throw new RoutingException(event.getMessage(), event.getEndpoint(), te);
58 }
59 }
60 }