1 /*
2 * Copyright 2005 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springframework.ws.server.endpoint;
18
19 import javax.xml.transform.Source;
20 import javax.xml.transform.sax.SAXResult;
21
22 import org.springframework.xml.transform.TransformerObjectSupport;
23 import org.xml.sax.ContentHandler;
24
25 /**
26 * Abstract base class for endpoints that handle the message payload with a SAX <code>ContentHandler</code>. Allows
27 * subclasses to create a response by returning a <code>Source</code>.
28 * <p/>
29 * Implementations of this class should create a new handler for each call of <code>createContentHandler</code>, because
30 * of thread safety. The handlers is later passed on to <code>createResponse</code>, so it can be used for holding
31 * request-specific state.
32 *
33 * @author Arjen Poutsma
34 * @see #createContentHandler()
35 * @see #getResponse(org.xml.sax.ContentHandler)
36 * @since 1.0.0
37 */
38 public abstract class AbstractSaxPayloadEndpoint extends TransformerObjectSupport implements PayloadEndpoint {
39
40 /**
41 * Invokes the provided <code>ContentHandler</code> on the given request. After parsing has been done, the provided
42 * response is returned.
43 *
44 * @see #createContentHandler()
45 * @see #getResponse(org.xml.sax.ContentHandler)
46 */
47 public final Source invoke(Source request) throws Exception {
48 ContentHandler contentHandler = null;
49 if (request != null) {
50 contentHandler = createContentHandler();
51 SAXResult result = new SAXResult(contentHandler);
52 transform(request, result);
53 }
54 return getResponse(contentHandler);
55 }
56
57 /**
58 * Returns the SAX <code>ContentHandler</code> used to parse the incoming request payload. A new instance should be
59 * created for each call, because of thread-safety. The content handler can be used to hold request-specific state.
60 * <p/>
61 * If an incoming message does not contain a payload, this method will not be invoked.
62 *
63 * @return a SAX content handler to be used for parsing
64 */
65 protected abstract ContentHandler createContentHandler() throws Exception;
66
67 /**
68 * Returns the response to be given, if any. This method is called after the request payload has been parsed using
69 * the SAX <code>ContentHandler</code>. The passed <code>ContentHandler</code> is created by {@link
70 * #createContentHandler()}: it can be used to hold request-specific state.
71 * <p/>
72 * If an incoming message does not contain a payload, this method will be invoked with <code>null</code> as content
73 * handler.
74 *
75 * @param contentHandler the content handler used to parse the request
76 */
77 protected abstract Source getResponse(ContentHandler contentHandler) throws Exception;
78 }