TemplateSource


1   /*
2    * $Id: TemplateSource.java,v 1.3 2004/12/01 07:54:28 hengels Exp $
3    * Copyright 2000,2005 wingS development team.
4    *
5    * This file is part of wingS (http://www.j-wings.org).
6    *
7    * wingS is free software; you can redistribute it and/or modify
8    * it under the terms of the GNU Lesser General Public License
9    * as published by the Free Software Foundation; either version 2.1
10   * of the License, or (at your option) any later version.
11   *
12   * Please see COPYING for the complete licence.
13   */
14  package org.wings.template;
15  
16  import java.io.IOException  ;
17  import java.io.InputStream  ;
18  
19  /**
20   * A TemplateSource for a Template. This encapsulates what is the notion
21   * of a template from the parsers point of view: some named entity, that
22   * might change over time and thus has a modification time; an input stream
23   * to access the contents.
24   * <p/>
25   * So <CODE>TemplateSource</CODE> is a general source where templates can come
26   * from. You can think of Files, URLs, Database-BLOBS ..
27   *
28   * @author <A HREF="mailto:H.Zeller@acm.org">Henner Zeller</A>
29   * @version $Revision: 1.3 $ $Date: 2004/12/01 07:54:28 $
30   */
31  public interface TemplateSource {
32      /**
33       * Returns a canonical name of this TemplateSource.
34       * <p/>
35       * The name returned here is used to look up the parsing
36       * result of the internal caching, so it should differ
37       * for all different Sources :-)
38       * May return <code>null</code> if this Source is supposed
39       * to be parsed each time. The canonical name would be something
40       * like a filename or an URL.
41       *
42       * @return the canonical name of the source. like 'file:/web/template.html'
43       */
44      String   getCanonicalName();
45  
46      /**
47       * Returns the time the content of this TemplateSource
48       * was last modified.
49       * <p/>
50       * The return value is used to decide whether to reparse a
51       * Source or not. Reparsing is done if the value returned
52       * here <em>differs</em> from the value returned at the last processing
53       * time. This may not return a 'real' time, it needs just
54       * to be comparable to itself; so some sort of version counter instead
55       * of time would be perfect as well.
56       *
57       * @return long a modification time
58       */
59      long lastModified();
60  
61      /**
62       * Gets an InputStream of this TemplateSource.
63       * <p/>
64       * <em>Note</em>
65       * that this method may be called twice if the page has to
66       * be parsed first. So you probably have to implement a
67       * buffer if your underlying source is transient ..
68       *
69       * @return an InputStream the content of the template is read from.
70       */
71      InputStream   getInputStream() throws IOException  ;
72  }
73  
74  
75  
76  
77
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