/*

 * Copyright (c) 2008, 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.beans.decoder;

/**

 * This class is intended to handle <var> element.

 * This element retrieves the value of specified variable.

 * For example:<pre>

 * &lt;var id="id1" idref="id2"/&gt;</pre>

 * is equivalent to {@code id1 = id2} in Java code.

 * <p>The following attributes are supported:

 * <dl>

 * <dt>idref

 * <dd>the identifier to refer to the variable

 * <dt>id

 * <dd>the identifier of the variable that is intended to store the result

 * </dl>

 *

 * @since 1.7

 *

 * @author Sergey A. Malenkov

 */

final class VarElementHandler extends ElementHandler {

    private ValueObject value;

    /**

     * Parses attributes of the element.

     * The following attributes are supported:

     * <dl>

     * <dt>idref

     * <dd>the identifier to refer to the variable

     * <dt>id

     * <dd>the identifier of the variable that is intended to store the result

     * </dl>

     *

     * @param name   the attribute name

     * @param value  the attribute value

     */

    @Override

    public void addAttribute(String name, String value) {

        if (name.equals("idref")) { // NON-NLS: the attribute name

            this.value = ValueObjectImpl.create(getVariable(value));

        } else {

            super.addAttribute(name, value);

        }

    }

    /**

     * Returns the value of this element.

     *

     * @return the value of this element

     */

    @Override

    protected ValueObject getValueObject() {

        if (this.value == null) {

            throw new IllegalArgumentException("Variable name is not set");

        }

        return this.value;

    }

}