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 */ 019package org.apache.wiki.api.filters; 020 021import java.util.Properties; 022 023import org.apache.wiki.WikiContext; 024import org.apache.wiki.WikiEngine; 025import org.apache.wiki.api.exceptions.FilterException; 026 027/** 028 * Provides a definition for a page filter. A page filter is a class 029 * that can be used to transform the WikiPage content being saved or 030 * being loaded at any given time. 031 * <p> 032 * Note that the WikiContext.getPage() method always returns the context 033 * in which text is rendered, i.e. the original request. Thus the content 034 * may actually be different content than what what the wikiContext.getPage() 035 * implies! This happens often if you are for example including multiple 036 * pages on the same page. 037 * <p> 038 * PageFilters must be thread-safe! There is only one instance of each PageFilter 039 * per each WikiEngine invocation. If you need to store data persistently, use 040 * VariableManager, or WikiContext. 041 * <p> 042 * As of 2.5.30, initialize() gains access to the WikiEngine. 043 * 044 */ 045public interface PageFilter 046{ 047 /** 048 * Is called whenever the a new PageFilter is instantiated and 049 * reset. 050 * 051 * @param engine The WikiEngine whic owns this PageFilter 052 * @param properties The properties ripped from filters.xml. 053 * @throws FilterException If the filter could not be initialized. If this is thrown, 054 * the filter is not added to the internal queues. 055 */ 056 void initialize( WikiEngine engine, Properties properties ) 057 throws FilterException; 058 059 /** 060 * This method is called whenever a page has been loaded from the provider, 061 * but not yet been sent through the markup-translation process. Note that you cannot 062 * do HTML translation here, because it will be escaped. 063 * 064 * @param wikiContext The current wikicontext. 065 * @param content WikiMarkup. 066 * @return The modified wikimarkup content. 067 * @throws FilterException If something goes wrong. Throwing this causes the entire page 068 * processing to be abandoned. 069 */ 070 String preTranslate( WikiContext wikiContext, String content ) 071 throws FilterException; 072 073 /** 074 * This method is called after a page has been fed through the translation process, 075 * so anything you are seeing here is translated content. If you want to 076 * do any of your own WikiMarkup2HTML translation, do it here. 077 * 078 * @param wikiContext The WikiContext. 079 * @param htmlContent The translated HTML 080 * @return The modified HTML 081 * 082 * @throws FilterException If something goes wrong. Throwing this causes the entire page 083 * processing to be abandoned. 084 */ 085 String postTranslate( WikiContext wikiContext, String htmlContent ) 086 throws FilterException; 087 088 /** 089 * This method is called before the page has been saved to the PageProvider. 090 * 091 * @param wikiContext The WikiContext 092 * @param content The wikimarkup that the user just wanted to save. 093 * @return The modified wikimarkup 094 * @throws FilterException If something goes wrong. Throwing this causes the entire page 095 * processing to be abandoned. 096 */ 097 String preSave( WikiContext wikiContext, String content ) 098 throws FilterException; 099 100 /** 101 * This method is called after the page has been successfully saved. 102 * If the saving fails for any reason, then this method will not 103 * be called. 104 * <p> 105 * Since the result is discarded from this method, this is only useful 106 * for things like counters, etc. 107 * 108 * @param wikiContext The WikiContext 109 * @param content The content which was just stored. 110 * @throws FilterException If something goes wrong. As the page is already saved, 111 * This is just logged. 112 */ 113 void postSave( WikiContext wikiContext, String content ) 114 throws FilterException; 115 116 /** 117 * Called for every filter, e.g. on wiki engine shutdown. Use this if you have to 118 * clean up or close global resources you allocated in the initialize() method. 119 * 120 * @param engine The WikiEngine which owns this filter. 121 * @since 2.5.36 122 */ 123 void destroy( WikiEngine engine ); 124 125}