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1   /*
2    * Copyright 2004 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  package com.nordija.tapestry.bayeux.stream;
17  
18  import org.apache.tapestry.IRequestCycle;
19  import org.apache.tapestry.engine.IEngineService;
20  import org.apache.tapestry.engine.ILink;
21  import org.apache.tapestry.link.AbstractLinkComponent;
22  import org.apache.tapestry.link.DirectLink;
23  
24  /**
25   * Renders a link to the stream service.
26   * <p/>
27   * The link acts much like the {@link DirectLink} but renders a link to the {@link StreamService}  an id for the resource to be streamed.
28   *
29   * @author Jacob von Eyben www.nordija.com
30   * @version $Id: StreamLink.java 131 2007-06-05 19:31:21Z jeyben $
31   * @see com.nordija.tapestry.bayeux.stream.StreamService
32   */
33  public abstract class StreamLink extends AbstractLinkComponent implements IStream {
34  
35      /**
36       * The parameters passed to the StreamService and further to the specified StreamResourceSourceExtention.
37       *
38       * @return
39       */
40      public abstract Object getParameters();
41  
42      /**
43       * todo: document
44       *
45       * @return
46       */
47      public abstract String getStreamResourceSourceExtentionName();
48  
49      /**
50       * todo: document
51       *
52       * @return
53       */
54      public abstract IEngineService getStreamService();
55  
56      /**
57       * todo: document
58       *
59       * @param cycle
60       * @return
61       */
62      public ILink getLink(IRequestCycle cycle) {
63          Object[] serviceParameters = DirectLink.constructServiceParameters(getParameters());
64          StreamServiceParameter ssp = new StreamServiceParameter(this, getStreamResourceSourceExtentionName(), serviceParameters);
65          return getStreamService().getLink(isStateful(), ssp);
66      }
67  }