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 */ 019 020 // 021 // This source code implements specifications defined by the Java 022 // Community Process. In order to remain compliant with the specification 023 // DO NOT add / change / or delete method signatures! 024 // 025 026 package javax.servlet.jsp.tagext; 027 028 import java.util.Map; 029 030 /** 031 * Translation-time validator class for a JSP page. 032 * A validator operates on the XML view associated with the JSP page. 033 * 034 * <p> 035 * The TLD file associates a TagLibraryValidator class and some init 036 * arguments with a tag library. 037 * 038 * <p> 039 * The JSP container is reponsible for locating an appropriate 040 * instance of the appropriate subclass by 041 * 042 * <ul> 043 * <li> new a fresh instance, or reuse an available one 044 * <li> invoke the setInitParams(Map) method on the instance 045 * </ul> 046 * 047 * once initialized, the validate(String, String, PageData) method will 048 * be invoked, where the first two arguments are the prefix 049 * and uri for this tag library in the XML View. The prefix is intended 050 * to make it easier to produce an error message. However, it is not 051 * always accurate. In the case where a single URI is mapped to more 052 * than one prefix in the XML view, the prefix of the first URI is provided. 053 * Therefore, to provide high quality error messages in cases where the 054 * tag elements themselves are checked, the prefix parameter should be 055 * ignored and the actual prefix of the element should be used instead. 056 * TagLibraryValidators should always use the uri to identify elements 057 * as beloning to the tag library, not the prefix. 058 * 059 * <p> 060 * A TagLibraryValidator instance 061 * may create auxiliary objects internally to perform 062 * the validation (e.g. an XSchema validator) and may reuse it for all 063 * the pages in a given translation run. 064 * 065 * <p> 066 * The JSP container is not guaranteed to serialize invocations of 067 * validate() method, and TagLibraryValidators should perform any 068 * synchronization they may require. 069 * 070 * <p> 071 * As of JSP 2.0, a JSP container must provide a jsp:id attribute to 072 * provide higher quality validation errors. 073 * The container will track the JSP pages 074 * as passed to the container, and will assign to each element 075 * a unique "id", which is passed as the value of the jsp:id 076 * attribute. Each XML element in the XML view available will 077 * be extended with this attribute. The TagLibraryValidator 078 * can then use the attribute in one or more ValidationMessage 079 * objects. The container then, in turn, can use these 080 * values to provide more precise information on the location 081 * of an error. 082 * 083 * <p> 084 * The actual prefix of the <code>id</code> attribute may or may not be 085 * <code>jsp</code> but it will always map to the namespace 086 * <code>http://java.sun.com/JSP/Page</code>. A TagLibraryValidator 087 * implementation must rely on the uri, not the prefix, of the <code>id</code> 088 * attribute. 089 */ 090 091 abstract public class TagLibraryValidator { 092 093 /** 094 * Sole constructor. (For invocation by subclass constructors, 095 * typically implicit.) 096 */ 097 public TagLibraryValidator() { 098 } 099 100 /** 101 * Set the init data in the TLD for this validator. 102 * Parameter names are keys, and parameter values are the values. 103 * 104 * @param map A Map describing the init parameters 105 */ 106 public void setInitParameters(Map map) { 107 initParameters = map; 108 } 109 110 111 /** 112 * Get the init parameters data as an immutable Map. 113 * Parameter names are keys, and parameter values are the values. 114 * 115 * @return The init parameters as an immutable map. 116 */ 117 public Map getInitParameters() { 118 return initParameters; 119 } 120 121 /** 122 * Validate a JSP page. 123 * This will get invoked once per unique tag library URI in the 124 * XML view. This method will return null if the page is valid; otherwise 125 * the method should return an array of ValidationMessage objects. 126 * An array of length zero is also interpreted as no errors. 127 * 128 * @param prefix the first prefix with which the tag library is 129 * associated, in the XML view. Note that some tags may use 130 * a different prefix if the namespace is redefined. 131 * @param uri the tag library's unique identifier 132 * @param page the JspData page object 133 * @return A null object, or zero length array if no errors, an array 134 * of ValidationMessages otherwise. 135 */ 136 public ValidationMessage[] validate(String prefix, String uri, 137 PageData page) 138 { 139 return null; 140 } 141 142 /** 143 * Release any data kept by this instance for validation purposes. 144 */ 145 public void release() { 146 initParameters = null; 147 } 148 149 // Private data 150 private Map initParameters; 151 152 }