01: /*
02: JSPWiki - a JSP-based WikiWiki clone.
03:
04: Copyright (C) 2001-2002 Janne Jalkanen (Janne.Jalkanen@iki.fi)
05:
06: This program is free software; you can redistribute it and/or modify
07: it under the terms of the GNU Lesser General Public License as published by
08: the Free Software Foundation; either version 2.1 of the License, or
09: (at your option) any later version.
10:
11: This program is distributed in the hope that it will be useful,
12: but WITHOUT ANY WARRANTY; without even the implied warranty of
13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14: GNU Lesser General Public License for more details.
15:
16: You should have received a copy of the GNU Lesser General Public License
17: along with this program; if not, write to the Free Software
18: Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19: */
20: package com.ecyrd.jspwiki.diff;
21:
22: import java.io.IOException;
23: import java.util.Properties;
24:
25: import com.ecyrd.jspwiki.NoRequiredPropertyException;
26: import com.ecyrd.jspwiki.WikiContext;
27: import com.ecyrd.jspwiki.WikiEngine;
28: import com.ecyrd.jspwiki.WikiProvider;
29:
30: /**
31: * Provides an SPI for creating a diff between two page versions.
32: */
33: public interface DiffProvider extends WikiProvider {
34: /**
35: * The return string is to be XHTML compliant ready to display html. No further
36: * processing of this text will be done by the wiki engine.
37: *
38: * @return An XHTML diff.
39: * @param context The Wiki Context
40: * @param oldWikiText the old text
41: * @param newWikiText the new text
42: */
43: public String makeDiffHtml(WikiContext context, String oldWikiText,
44: String newWikiText);
45:
46: /**
47: * If there is no diff provider set, this provider will work instead.
48: */
49: public static class NullDiffProvider implements DiffProvider {
50: /**
51: * {@inheritDoc}
52: */
53: public String makeDiffHtml(WikiContext ctx, String oldWikiText,
54: String newWikiText) {
55: return "You are using the NullDiffProvider, check your properties file.";
56: }
57:
58: /**
59: * {@inheritDoc}
60: */
61: public void initialize(WikiEngine engine, Properties properties)
62: throws NoRequiredPropertyException, IOException {
63: }
64:
65: /**
66: * {@inheritDoc}
67: */
68: public String getProviderInfo() {
69: return "NullDiffProvider";
70: }
71: }
72:
73: }
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