ValueTaglet.java revision 3233:b5d08bc0d224
1/* 2 * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package jdk.javadoc.internal.doclets.toolkit.taglets; 27 28 29import javax.lang.model.element.Element; 30import javax.lang.model.element.TypeElement; 31import javax.lang.model.element.VariableElement; 32import javax.lang.model.util.Elements; 33 34import com.sun.source.doctree.DocTree; 35import jdk.javadoc.internal.doclets.toolkit.Configuration; 36import jdk.javadoc.internal.doclets.toolkit.Content; 37import jdk.javadoc.internal.doclets.toolkit.util.CommentHelper; 38import jdk.javadoc.internal.doclets.toolkit.util.Utils; 39 40import static com.sun.source.doctree.DocTree.Kind.*; 41 42/** 43 * An inline Taglet representing the value tag. This tag should only be used with 44 * constant fields that have a value. It is used to access the value of constant 45 * fields. This inline tag has an optional field name parameter. If the name is 46 * specified, the constant value is retrieved from the specified field. A link 47 * is also created to the specified field. If a name is not specified, the value 48 * is retrieved for the field that the inline tag appears on. The name is specifed 49 * in the following format: [fully qualified class name]#[constant field name]. 50 * 51 * <p><b>This is NOT part of any supported API. 52 * If you write code that depends on this, you do so at your own risk. 53 * This code and its internal interfaces are subject to change or 54 * deletion without notice.</b> 55 * 56 * @author Jamie Ho 57 */ 58 59public class ValueTaglet extends BaseInlineTaglet { 60 61 /** 62 * Construct a new ValueTaglet. 63 */ 64 public ValueTaglet() { 65 name = VALUE.tagName; 66 } 67 68 /** 69 * Will return false because this inline tag may 70 * only appear in Fields. 71 * @return false since this is not a method. 72 */ 73 public boolean inMethod() { 74 return true; 75 } 76 77 /** 78 * Will return false because this inline tag may 79 * only appear in Fields. 80 * @return false since this is not a method. 81 */ 82 public boolean inConstructor() { 83 return true; 84 } 85 86 /** 87 * Will return false because this inline tag may 88 * only appear in Fields. 89 * @return false since this is not a method. 90 */ 91 public boolean inOverview() { 92 return true; 93 } 94 95 /** 96 * Will return false because this inline tag may 97 * only appear in Fields. 98 * @return false since this is not a method. 99 */ 100 public boolean inPackage() { 101 return true; 102 } 103 104 /** 105 * Will return false because this inline tag may 106 * only appear in Fields. 107 * @return false since this is not a method. 108 */ 109 public boolean inType() { 110 return true; 111 } 112 113 /** 114 * Given the name of the field, return the corresponding VariableElement. Return null 115 * due to invalid use of value tag if the name is null or empty string and if 116 * the value tag is not used on a field. 117 * 118 * @param holder the element holding the tag 119 * @param config the current configuration of the doclet. 120 * @param tag the value tag. 121 * 122 * @return the corresponding VariableElement. If the name is null or empty string, 123 * return field that the value tag was used in. Return null if the name is null 124 * or empty string and if the value tag is not used on a field. 125 */ 126 private VariableElement getVariableElement(Element holder, Configuration config, DocTree tag) { 127 Utils utils = config.utils; 128 CommentHelper ch = utils.getCommentHelper(holder); 129 String signature = ch.getReferencedSignature(tag); 130 131 if (signature == null) { // no reference 132 //Base case: no label. 133 if (utils.isVariableElement(holder)) { 134 return (VariableElement)(holder); 135 } else { 136 // If the value tag does not specify a parameter which is a valid field and 137 // it is not used within the comments of a valid field, return null. 138 return null; 139 } 140 } 141 142 String[] sigValues = signature.split("#"); 143 String memberName = null; 144 TypeElement te = null; 145 if (sigValues.length == 1) { 146 //Case 2: @value in same class. 147 if (utils.isExecutableElement(holder) || utils.isVariableElement(holder)) { 148 te = utils.getEnclosingTypeElement(holder); 149 } else if (utils.isTypeElement(holder)) { 150 te = utils.getTopMostContainingTypeElement(holder); 151 } 152 memberName = sigValues[0]; 153 } else { 154 //Case 3: @value in different class. 155 Elements elements = config.root.getElementUtils(); 156 te = elements.getTypeElement(sigValues[0]); 157 memberName = sigValues[1]; 158 } 159 if (te == null) { 160 return null; 161 } 162 for (Element field : utils.getFields(te)) { 163 if (utils.getSimpleName(field).equals(memberName)) { 164 return (VariableElement)field; 165 } 166 } 167 return null; 168 } 169 170 /** 171 * {@inheritDoc} 172 */ 173 public Content getTagletOutput(Element holder, DocTree tag, TagletWriter writer) { 174 Utils utils = writer.configuration().utils; 175 VariableElement field = getVariableElement(holder, writer.configuration(), tag); 176 if (field == null) { 177 if (tag.toString().isEmpty()) { 178 //Invalid use of @value 179 writer.getMsgRetriever().warning(holder, 180 "doclet.value_tag_invalid_use"); 181 } else { 182 //Reference is unknown. 183 writer.getMsgRetriever().warning(holder, 184 "doclet.value_tag_invalid_reference", tag.toString()); 185 } 186 } else if (field.getConstantValue() != null) { 187 return writer.valueTagOutput(field, 188 utils.constantValueExpresion(field), 189 // TODO: investigate and cleanup 190 // in the j.l.m world, equals will not be accurate 191 // !field.equals(tag.holder()) 192 !utils.elementsEqual(field, holder) 193 ); 194 } else { 195 //Referenced field is not a constant. 196 writer.getMsgRetriever().warning(holder, 197 "doclet.value_tag_invalid_constant", utils.getSimpleName(field)); 198 } 199 return writer.getOutputInstance(); 200 } 201} 202