001/* 002 Licensed to the Apache Software Foundation (ASF) under one 003 or more contributor license agreements. See the NOTICE file 004 distributed with this work for additional information 005 regarding copyright ownership. The ASF licenses this file 006 to you under the Apache License, Version 2.0 (the 007 "License"); you may not use this file except in compliance 008 with the License. You may obtain a copy of the License at 009 010 http://www.apache.org/licenses/LICENSE-2.0 011 012 Unless required by applicable law or agreed to in writing, 013 software distributed under the License is distributed on an 014 "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 KIND, either express or implied. See the License for the 016 specific language governing permissions and limitations 017 under the License. 018*/ 019 020package org.apache.wiki.diff; 021 022import org.apache.logging.log4j.LogManager; 023import org.apache.logging.log4j.Logger; 024import org.apache.wiki.api.core.Context; 025import org.apache.wiki.api.core.Engine; 026import org.apache.wiki.api.exceptions.NoRequiredPropertyException; 027import org.apache.wiki.api.providers.PageProvider; 028import org.apache.wiki.pages.PageManager; 029import org.apache.wiki.util.ClassUtil; 030 031import java.io.IOException; 032import java.util.Properties; 033 034 035/** 036 * Load, initialize and delegate to the DiffProvider that will actually do the work. 037 */ 038public class DefaultDifferenceManager implements DifferenceManager { 039 040 private static final Logger LOG = LogManager.getLogger( DefaultDifferenceManager.class ); 041 042 private DiffProvider m_provider; 043 044 /** 045 * Creates a new DifferenceManager for the given engine. 046 * 047 * @param engine The Engine. 048 * @param props A set of properties. 049 */ 050 public DefaultDifferenceManager( final Engine engine, final Properties props ) { 051 loadProvider( props ); 052 initializeProvider( engine, props ); 053 054 LOG.info( "Using difference provider: " + m_provider.getProviderInfo() ); 055 } 056 057 private void loadProvider( final Properties props ) { 058 final String providerClassName = props.getProperty( PROP_DIFF_PROVIDER, TraditionalDiffProvider.class.getName() ); 059 try { 060 m_provider = ClassUtil.buildInstance( "org.apache.wiki.diff", providerClassName ); 061 } catch( final ReflectiveOperationException e ) { 062 LOG.warn( "Failed loading DiffProvider, will use NullDiffProvider.", e ); 063 } 064 065 if( m_provider == null ) { 066 m_provider = new DiffProvider.NullDiffProvider(); 067 } 068 } 069 070 071 private void initializeProvider( final Engine engine, final Properties props ) { 072 try { 073 m_provider.initialize( engine, props ); 074 } catch( final NoRequiredPropertyException | IOException e ) { 075 LOG.warn( "Failed initializing DiffProvider, will use NullDiffProvider.", e ); 076 m_provider = new DiffProvider.NullDiffProvider(); //doesn't need init'd 077 } 078 } 079 080 /** 081 * Returns valid XHTML string to be used in any way you please. 082 * 083 * @param context The Wiki Context 084 * @param firstWikiText The old text 085 * @param secondWikiText the new text 086 * @return XHTML, or empty string, if no difference detected. 087 */ 088 @Override 089 public String makeDiff( final Context context, final String firstWikiText, final String secondWikiText ) { 090 String diff; 091 try { 092 diff = m_provider.makeDiffHtml( context, firstWikiText, secondWikiText ); 093 094 if( diff == null ) { 095 diff = ""; 096 } 097 } catch( final Exception e ) { 098 diff = "Failed to create a diff, check the logs."; 099 LOG.warn( diff, e ); 100 } 101 return diff; 102 } 103 104 /** 105 * Returns a diff of two versions of a page. 106 * <p> 107 * Note that the API was changed in 2.6 to provide a WikiContext object! 108 * 109 * @param context The WikiContext of the page you wish to get a diff from 110 * @param version1 Version number of the old page. If WikiPageProvider.LATEST_VERSION (-1), then uses current page. 111 * @param version2 Version number of the new page. If WikiPageProvider.LATEST_VERSION (-1), then uses current page. 112 * 113 * @return A HTML-ized difference between two pages. If there is no difference, returns an empty string. 114 */ 115 @Override 116 public String getDiff( final Context context, final int version1, final int version2 ) { 117 final String page = context.getPage().getName(); 118 String page1 = context.getEngine().getManager( PageManager.class ).getPureText( page, version1 ); 119 final String page2 = context.getEngine().getManager( PageManager.class ).getPureText( page, version2 ); 120 121 // Kludge to make diffs for new pages to work this way. 122 if( version1 == PageProvider.LATEST_VERSION ) { 123 page1 = ""; 124 } 125 126 return makeDiff( context, page1, page2 ); 127 } 128 129} 130