/*
 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
 * 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
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package jdk.javadoc.internal.doclets.toolkit.taglets;

import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;

import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.type.TypeMirror;

import com.sun.source.doctree.DocTree;
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.DocFinder;
import jdk.javadoc.internal.doclets.toolkit.util.DocFinder.Input;
import jdk.javadoc.internal.doclets.toolkit.util.Utils;

import static com.sun.source.doctree.DocTree.Kind.RETURN;

A taglet that represents the @return tag.
 
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.
Author:
Jamie Ho/**
 * A taglet that represents the @return tag.
 *
 *  <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 ReturnTaglet extends BaseTaglet implements InheritableTaglet {

    public ReturnTaglet() {
        super(RETURN.tagName, false, EnumSet.of(Site.METHOD));
    }

    @Override
    public void inherit(DocFinder.Input input, DocFinder.Output output) {
        List<? extends DocTree> tags = input.utils.getBlockTags(input.element, DocTree.Kind.RETURN);
        CommentHelper ch = input.utils.getCommentHelper(input.element);
        if (!tags.isEmpty()) {
            output.holder = input.element;
            output.holderTag = tags.get(0);
            output.inlineTags = input.isFirstSentence
                    ? ch.getFirstSentenceTrees(input.utils.configuration, output.holderTag)
                    : ch.getDescription(input.utils.configuration, output.holderTag);
        }
    }

    @Override
    public Content getTagletOutput(Element holder, TagletWriter writer) {
        Messages messages = writer.configuration().getMessages();
        Utils utils = writer.configuration().utils;
        TypeMirror returnType = utils.getReturnType((ExecutableElement)holder);
        List<? extends DocTree> tags = utils.getBlockTags(holder, name);

        //Make sure we are not using @return tag on method with void return type.
        if (returnType != null && utils.isVoid(returnType)) {
            if (!tags.isEmpty()) {
                messages.warning(holder, "doclet.Return_tag_on_void_method");
            }
            return null;
        }
        if (!tags.isEmpty())
            return writer.returnTagOutput(holder, tags.get(0));
        //Inherit @return tag if necessary.
        List<DocTree> ntags = new ArrayList<>();
        Input input = new DocFinder.Input(utils, holder, this);
        DocFinder.Output inheritedDoc = DocFinder.search(writer.configuration(), input);
        if (inheritedDoc.holderTag != null) {
            CommentHelper ch = utils.getCommentHelper(input.element);
            ch.setOverrideElement(inheritedDoc.holder);
            ntags.add(inheritedDoc.holderTag);
        }
        return !ntags.isEmpty() ? writer.returnTagOutput(holder, ntags.get(0)) : null;
    }
}