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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package jdk.javadoc.internal.doclets.toolkit.taglets;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.util.Elements;
import com.sun.source.doctree.DocTree;
import jdk.javadoc.internal.doclets.toolkit.Configuration;
import jdk.javadoc.internal.doclets.toolkit.Content;
import jdk.javadoc.internal.doclets.toolkit.Messages;
import jdk.javadoc.internal.doclets.toolkit.util.CommentHelper;
import jdk.javadoc.internal.doclets.toolkit.util.Utils;
import static com.sun.source.doctree.DocTree.Kind.*;
/**
* An inline Taglet representing the value tag. This tag should only be used with
* constant fields that have a value. It is used to access the value of constant
* fields. This inline tag has an optional field name parameter. If the name is
* specified, the constant value is retrieved from the specified field. A link
* is also created to the specified field. If a name is not specified, the value
* is retrieved for the field that the inline tag appears on. The name is specifed
* in the following format: [fully qualified class name]#[constant field name].
*
* <p><b>This is NOT part of any supported API.
* If you write code that depends on this, you do so at your own risk.
* This code and its internal interfaces are subject to change or
* deletion without notice.</b>
*
* @author Jamie Ho
*/
public class ValueTaglet extends BaseInlineTaglet {
/**
* Construct a new ValueTaglet.
*/
public ValueTaglet() {
name = VALUE.tagName;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a method.
*/
public boolean inMethod() {
return true;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a method.
*/
public boolean inConstructor() {
return true;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a method.
*/
public boolean inOverview() {
return true;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a field.
*/
public boolean inModule() {
return false;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a method.
*/
public boolean inPackage() {
return true;
}
/**
* Will return false because this inline tag may
* only appear in Fields.
* @return false since this is not a method.
*/
public boolean inType() {
return true;
}
/**
* Given the name of the field, return the corresponding VariableElement. Return null
* due to invalid use of value tag if the name is null or empty string and if
* the value tag is not used on a field.
*
* @param holder the element holding the tag
* @param config the current configuration of the doclet.
* @param tag the value tag.
*
* @return the corresponding VariableElement. If the name is null or empty string,
* return field that the value tag was used in. Return null if the name is null
* or empty string and if the value tag is not used on a field.
*/
private VariableElement getVariableElement(Element holder, Configuration config, DocTree tag) {
Utils utils = config.utils;
CommentHelper ch = utils.getCommentHelper(holder);
String signature = ch.getReferencedSignature(tag);
if (signature == null) { // no reference
//Base case: no label.
if (utils.isVariableElement(holder)) {
return (VariableElement)(holder);
} else {
// If the value tag does not specify a parameter which is a valid field and
// it is not used within the comments of a valid field, return null.
return null;
}
}
String[] sigValues = signature.split("#");
String memberName = null;
TypeElement te = null;
if (sigValues.length == 1) {
//Case 2: @value in same class.
if (utils.isExecutableElement(holder) || utils.isVariableElement(holder)) {
te = utils.getEnclosingTypeElement(holder);
} else if (utils.isTypeElement(holder)) {
te = utils.getTopMostContainingTypeElement(holder);
}
memberName = sigValues[0];
} else {
//Case 3: @value in different class.
Elements elements = config.docEnv.getElementUtils();
te = elements.getTypeElement(sigValues[0]);
memberName = sigValues[1];
}
if (te == null) {
return null;
}
for (Element field : utils.getFields(te)) {
if (utils.getSimpleName(field).equals(memberName)) {
return (VariableElement)field;
}
}
return null;
}
/**
* {@inheritDoc}
*/
public Content getTagletOutput(Element holder, DocTree tag, TagletWriter writer) {
Utils utils = writer.configuration().utils;
Messages messages = writer.configuration().getMessages();
VariableElement field = getVariableElement(holder, writer.configuration(), tag);
if (field == null) {
if (tag.toString().isEmpty()) {
//Invalid use of @value
messages.warning(holder,
"doclet.value_tag_invalid_use");
} else {
//Reference is unknown.
messages.warning(holder,
"doclet.value_tag_invalid_reference", tag.toString());
}
} else if (field.getConstantValue() != null) {
return writer.valueTagOutput(field,
utils.constantValueExpresion(field),
// TODO: investigate and cleanup
// in the j.l.m world, equals will not be accurate
// !field.equals(tag.holder())
!utils.elementsEqual(field, holder)
);
} else {
//Referenced field is not a constant.
messages.warning(holder,
"doclet.value_tag_invalid_constant", utils.getSimpleName(field));
}
return writer.getOutputInstance();
}
}