/*

 * Copyright (c) 2001, 2013, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.doclets.internal.toolkit.taglets;

import java.util.*;

import com.sun.javadoc.*;

import com.sun.tools.doclets.internal.toolkit.Configuration;

import com.sun.tools.doclets.internal.toolkit.Content;

import com.sun.tools.doclets.internal.toolkit.util.*;

/**

 * 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

 * @since 1.4

 */

public class ValueTaglet extends BaseInlineTaglet {

    /**

     * Construct a new ValueTaglet.

     */

    public ValueTaglet() {

        name = "value";

    }

    /**

     * 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 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 FieldDoc. 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 config the current configuration of the doclet.

     * @param tag the value tag.

     * @param name the name of the field to search for.  The name should be in

     * {@code <qualified class name>#<field name>} format. If the class name is omitted,

     * it is assumed that the field is in the current class.

     *

     * @return the corresponding FieldDoc. 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 FieldDoc getFieldDoc(Configuration config, Tag tag, String name) {

        if (name == null || name.length() == 0) {

            //Base case: no label.

            if (tag.holder() instanceof FieldDoc) {

                return (FieldDoc) tag.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;

            }

        }

        StringTokenizer st = new StringTokenizer(name, "#");

        String memberName = null;

        ClassDoc cd = null;

        if (st.countTokens() == 1) {

            //Case 2:  @value in same class.

            Doc holder = tag.holder();

            if (holder instanceof MemberDoc) {

                cd = ((MemberDoc) holder).containingClass();

            } else if (holder instanceof ClassDoc) {

                cd = (ClassDoc) holder;

            }

            memberName = st.nextToken();

        } else {

            //Case 3: @value in different class.

            cd = config.root.classNamed(st.nextToken());

            memberName = st.nextToken();

        }

        if (cd == null) {

            return null;

        }

        for (FieldDoc field : cd.fields()) {

            if (field.name().equals(memberName)) {

                return field;

            }

        }

        return null;

    }

    /**

     * {@inheritDoc}

     */

    public Content getTagletOutput(Tag tag, TagletWriter writer) {

        FieldDoc field = getFieldDoc(

            writer.configuration(), tag, tag.text());

        if (field == null) {

            if (tag.text().isEmpty()) {

                //Invalid use of @value

                writer.getMsgRetriever().warning(tag.holder().position(),

                        "doclet.value_tag_invalid_use");

            } else {

                //Reference is unknown.

                writer.getMsgRetriever().warning(tag.holder().position(),

                        "doclet.value_tag_invalid_reference", tag.text());

            }

        } else if (field.constantValue() != null) {

            return writer.valueTagOutput(field,

                field.constantValueExpression(),

                ! field.equals(tag.holder()));

        } else {

            //Referenced field is not a constant.

            writer.getMsgRetriever().warning(tag.holder().position(),

                "doclet.value_tag_invalid_constant", field.name());

        }

        return writer.getOutputInstance();

    }

}