/*

 * 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;

import java.lang.reflect.Array;

/**

 * This class is intended to handle <array> element,

 * that is used to array creation.

 * The {@code length} attribute specifies the length of the array.

 * The {@code class} attribute specifies the elements type.

 * The {@link Object} type is used by default.

 * For example:<pre>

 * &lt;array length="10"/&gt;</pre>

 * is equivalent to {@code new Component[10]} in Java code.

 * The {@code set} and {@code get} methods,

 * as defined in the {@link java.util.List} interface,

 * can be used as if they could be applied to array instances.

 * The {@code index} attribute can thus be used with arrays.

 * For example:<pre>

 * <array length="3" class="java.lang.String">

 *     <void index="1">

 *         <string>Hello, world</string>

 *     </void>

 * &lt;/array&gt;</pre>

 * is equivalent to the following Java code:<pre>

 * String[] s = new String[3];

 * s[1] = "Hello, world";</pre>

 * It is possible to omit the {@code length} attribute and

 * specify the values directly, without using {@code void} tags.

 * The length of the array is equal to the number of values specified.

 * For example:<pre>

 * <array id="array" class="int">

 *     <int>123</int>

 *     <int>456</int>

 * &lt;/array&gt;</pre>

 * is equivalent to {@code int[] array = {123, 456}} in Java code.

 * <dl>

 * <dt>length

 * <dd>the array length

 * <dt>class

 * <dd>the type of object for instantiation

 * <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 ArrayElementHandler extends NewElementHandler {

    private Integer length;

    /**

     * Parses attributes of the element.

     * <dl>

     * <dt>length

     * <dd>the array length

     * <dt>class

     * <dd>the type of object for instantiation

     * <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("length")) { // NON-NLS: the attribute name

            this.length = Integer.valueOf(value);

        } else {

            super.addAttribute(name, value);

        }

    }

    /**

     * Calculates the value of this element

     * if the lentgh attribute is set.

     */

    @Override

    public void startElement() {

        if (this.length != null) {

            getValueObject();

        }

    }

    /**

     * Tests whether the value of this element can be used

     * as an argument of the element that contained in this one.

     *

     * @return {@code true} if the value of this element can be used

     *         as an argument of the element that contained in this one,

     *         {@code false} otherwise

     */

    @Override

    protected boolean isArgument() {

        return true; // hack for compatibility

    }

    /**

     * Creates an instance of the array.

     *

     * @param type  the base class

     * @param args  the array of arguments

     * @return the value of this element

     */

    @Override

    protected ValueObject getValueObject(Class<?> type, Object[] args) {

        if (type == null) {

            type = Object.class;

        }

        if (this.length != null) {

            return ValueObjectImpl.create(Array.newInstance(type, this.length));

        }

        Object array = Array.newInstance(type, args.length);

        for (int i = 0; i < args.length; i++) {

            Array.set(array, i, args[i]);

        }

        return ValueObjectImpl.create(array);

    }

}