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	/*
	* 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.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 <new> 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>
	* <new class="java.lang.Long">
	* <string>10</string>
	* </new></pre>
	* is equivalent to {@code new Long("10")} in Java code.
	* <p>The following attributes 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 attributes 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;
	}
	}

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