/*

 * 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 com.sun.beans.finder.MethodFinder;

import java.lang.reflect.Method;

import sun.reflect.misc.MethodUtil;

/**

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

 * It describes invocation of the method.

 * The {@code name} attribute denotes

 * the name of the method to invoke.

 * If the {@code class} attribute is specified

 * this element invokes static method of specified class.

 * The inner elements specifies the arguments of the method.

 * For example:<pre>

 * <method name="valueOf" class="java.lang.Long">

 *     <string>10</string>

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

 * is equivalent to {@code Long.valueOf("10")} in Java code.

 * <p>The following attributes are supported:

 * <dl>

 * <dt>name

 * <dd>the method name

 * <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 MethodElementHandler extends NewElementHandler {

    private String name;

    /**

     * Parses attributes of the element.

     * The following attributes are supported:

     * <dl>

     * <dt>name

     * <dd>the method name

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

            this.name = value;

        } else {

            super.addAttribute(name, value);

        }

    }

    /**

     * Returns the result of method execution.

     *

     * @param type  the base class

     * @param args  the array of arguments

     * @return the value of this element

     * @throws Exception if calculation is failed

     */

    @Override

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

        Object bean = getContextBean();

        Class<?>[] types = getArgumentTypes(args);

        Method method = (type != null)

                ? MethodFinder.findStaticMethod(type, this.name, types)

                : MethodFinder.findMethod(bean.getClass(), this.name, types);

        if (method.isVarArgs()) {

            args = getArguments(args, method.getParameterTypes());

        }

        Object value = MethodUtil.invoke(method, bean, args);

        return method.getReturnType().equals(void.class)

                ? ValueObjectImpl.VOID

                : ValueObjectImpl.create(value);

    }

}