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/* * Copyright (c) 2008, 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.ConstructorFinder; import java.lang.reflect.Array;import java.lang.reflect.Constructor; import java.util.ArrayList;import java.util.List; /** * This class is intended to handle &lt;new&gt; element. * It describes instantiation of the object. * The {@code class} attribute denotes * the name of the class to instantiate. * The inner elements specifies the arguments of the constructor. * For example:<pre> * &lt;new class="java.lang.Long"&gt; *     &lt;string&gt;10&lt;/string&gt; * &lt;/new&gt;</pre> * is equivalent to {@code new Long("10")} in Java code. * <p>The following atributes are supported: * <dl> * <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 */class NewElementHandler extends ElementHandler {    private List<Object> arguments = new ArrayList<Object>();    private ValueObject value = ValueObjectImpl.VOID;     private Class<?> type;     /**     * Parses attributes of the element.     * The following atributes are supported:     * <dl>     * <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("class")) { // NON-NLS: the attribute name            this.type = getOwner().findClass(value);        } else {            super.addAttribute(name, value);        }    }     /**     * Adds the argument to the list of arguments     * that is used to calculate the value of this element.     *     * @param argument  the value of the element that contained in this one     */    @Override    protected final void addArgument(Object argument) {        if (this.arguments == null) {            throw new IllegalStateException("Could not add argument to evaluated element");        }        this.arguments.add(argument);    }     /**     * Returns the context of the method.     * The context of the static method is the class object.     * The context of the non-static method is the value of the parent element.     *     * @return the context of the method     */    @Override    protected final Object getContextBean() {        return (this.type != null)                ? this.type                : super.getContextBean();    }     /**     * Returns the value of this element.     *     * @return the value of this element     */    @Override    protected final ValueObject getValueObject() {        if (this.arguments != null) {            try {                this.value = getValueObject(this.type, this.arguments.toArray());            }            catch (Exception exception) {                getOwner().handleException(exception);            }            finally {                this.arguments = null;            }        }        return this.value;    }     /**     * Calculates the value of this element     * using the base class and the array of arguments.     * By default, it creates an instance of the base class.     * This method should be overridden in those handlers     * that extend behavior of this element.     *     * @param type  the base class     * @param args  the array of arguments     * @return the value of this element     * @throws Exception if calculation is failed     */    ValueObject getValueObject(Class<?> type, Object[] args) throws Exception {        if (type == null) {            throw new IllegalArgumentException("Class name is not set");        }        Class<?>[] types = getArgumentTypes(args);        Constructor<?> constructor = ConstructorFinder.findConstructor(type, types);        if (constructor.isVarArgs()) {            args = getArguments(args, constructor.getParameterTypes());        }        return ValueObjectImpl.create(constructor.newInstance(args));    }     /**     * Converts the array of arguments to the array of corresponding classes.     * If argument is {@code null} the class is {@code null} too.     *     * @param arguments  the array of arguments     * @return the array of corresponding classes     */    static Class<?>[] getArgumentTypes(Object[] arguments) {        Class<?>[] types = new Class<?>[arguments.length];        for (int i = 0; i < arguments.length; i++) {            if (arguments[i] != null) {                types[i] = arguments[i].getClass();            }        }        return types;    }     /**     * Resolves variable arguments.     *     * @param arguments  the array of arguments     * @param types      the array of parameter types     * @return the resolved array of arguments     */    static Object[] getArguments(Object[] arguments, Class<?>[] types) {        int index = types.length - 1;        if (types.length == arguments.length) {            Object argument = arguments[index];            if (argument == null) {                return arguments;            }            Class<?> type = types[index];            if (type.isAssignableFrom(argument.getClass())) {                return arguments;            }        }        int length = arguments.length - index;        Class<?> type = types[index].getComponentType();        Object array = Array.newInstance(type, length);        System.arraycopy(arguments, index, array, 0, length);         Object[] args = new Object[types.length];        System.arraycopy(arguments, 0, args, 0, index);        args[index] = array;        return args;    }}