1 /*
2 * $Id: AbstractMessageAwareTransformer.java 11343 2008-03-13 10:58:26Z tcarlson $
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.transformer;
12
13 import org.mule.DefaultMuleMessage;
14 import org.mule.MuleServer;
15 import org.mule.RequestContext;
16 import org.mule.api.MuleEventContext;
17 import org.mule.api.MuleMessage;
18 import org.mule.api.transformer.TransformerException;
19 import org.mule.config.i18n.CoreMessages;
20
21 /**
22 * <code>AbstractMessageAwareTransformer</code> is a transformer that has a reference
23 * to the current message. This message can be used obtains properties associated
24 * with the current message useful to the transform. Note that when part of a
25 * transform chain, the Message payload reflects the pre-transform message state,
26 * unless there is no current event for this thread, then the message will be a new
27 * DefaultMuleMessage with the src as its payload. Transformers should always work on the
28 * src object not the message payload.
29 *
30 * @see org.mule.api.MuleMessage
31 * @see org.mule.DefaultMuleMessage
32 */
33
34 public abstract class AbstractMessageAwareTransformer extends AbstractTransformer
35 {
36
37 public boolean isSourceTypeSupported(Class aClass, boolean exactMatch)
38 {
39 //TODO RM* This is a bit of hack since we could just register MuleMessage as a supportedType, but this has some
40 //funny behaviour in certain ObjectToXml transformers
41 return (super.isSourceTypeSupported(aClass, exactMatch) || MuleMessage.class.isAssignableFrom(aClass));
42 }
43
44 public final Object doTransform(Object src, String encoding) throws TransformerException
45 {
46 MuleMessage message;
47 if(src instanceof MuleMessage)
48 {
49 message = (MuleMessage)src;
50 }
51 else if (MuleServer.getMuleContext().getConfiguration().isAutoWrapMessageAwareTransform())
52 {
53 message = new DefaultMuleMessage(src);
54 }
55 else
56 {
57 MuleEventContext event = RequestContext.getEventContext();
58 if (event == null)
59 {
60 throw new TransformerException(CoreMessages.noCurrentEventForTransformer(), this);
61 }
62 message = event.getMessage();
63 if(!message.getPayload().equals(src))
64 {
65 throw new IllegalStateException("Transform payload does not match current MuleEventContext payload");
66 }
67 }
68 return transform(message, encoding);
69 }
70
71 public abstract Object transform(MuleMessage message, String outputEncoding)
72 throws TransformerException;
73
74 }