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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.FieldFinder;

	import java.lang.reflect.Field;

	/**
	* This class is intended to handle <field> element.
	* This element simplifies access to the fields.
	* If the {@code class} attribute is specified
	* this element accesses static field of specified class.
	* This element defines getter if it contains no argument.
	* It returns the value of the field in this case.
	* For example:<pre>
	* <field name="TYPE" class="java.lang.Long"/></pre>
	* is equivalent to {@code Long.TYPE} in Java code.
	* This element defines setter if it contains one argument.
	* It does not return the value of the field in this case.
	* For example:<pre>
	* <field name="id"><int>0</int></field></pre>
	* is equivalent to {@code id = 0} in Java code.
	* <p>The following attributes are supported:
	* <dl>
	* <dt>name
	* <dd>the field name
	* <dt>class
	* <dd>the type is used for static fields only
	* <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 FieldElementHandler extends AccessorElementHandler {
	private Class<?> type;

	/**
	* Parses attributes of the element.
	* The following attributes are supported:
	* <dl>
	* <dt>name
	* <dd>the field name
	* <dt>class
	* <dd>the type is used for static fields only
	* <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);
	}
	}

	/**
	* 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 should be used
	* as an argument of the element that contained in this one,
	* {@code false} otherwise
	*/
	@Override
	protected boolean isArgument() {
	return super.isArgument() && (this.type != null); // only static accessor can be used an argument
	}

	/**
	* Returns the context of the field.
	* The context of the static field is the class object.
	* The context of the non-static field is the value of the parent element.
	*
	* @return the context of the field
	*/
	@Override
	protected Object getContextBean() {
	return (this.type != null)
	? this.type
	: super.getContextBean();
	}

	/**
	* Returns the value of the field with specified {@code name}.
	*
	* @param name the name of the field
	* @return the value of the specified field
	*/
	@Override
	protected Object getValue(String name) {
	try {
	return getFieldValue(getContextBean(), name);
	}
	catch (Exception exception) {
	getOwner().handleException(exception);
	}
	return null;
	}

	/**
	* Sets the new value for the field with specified {@code name}.
	*
	* @param name the name of the field
	* @param value the new value for the specified field
	*/
	@Override
	protected void setValue(String name, Object value) {
	try {
	setFieldValue(getContextBean(), name, value);
	}
	catch (Exception exception) {
	getOwner().handleException(exception);
	}
	}

	/**
	* Performs the search of the field with specified {@code name}
	* in specified context and returns its value.
	*
	* @param bean the context bean that contains field
	* @param name the name of the field
	* @return the value of the field
	* @throws IllegalAccessException if the field is not accesible
	* @throws NoSuchFieldException if the field is not found
	*/
	static Object getFieldValue(Object bean, String name) throws IllegalAccessException, NoSuchFieldException {
	return findField(bean, name).get(bean);
	}

	/**
	* Performs the search of the field with specified {@code name}
	* in specified context and updates its value.
	*
	* @param bean the context bean that contains field
	* @param name the name of the field
	* @param value the new value for the field
	* @throws IllegalAccessException if the field is not accesible
	* @throws NoSuchFieldException if the field is not found
	*/
	private static void setFieldValue(Object bean, String name, Object value) throws IllegalAccessException, NoSuchFieldException {
	findField(bean, name).set(bean, value);
	}

	/**
	* Performs the search of the field
	* with specified {@code name} in specified context.
	*
	* @param bean the context bean that contains field
	* @param name the name of the field
	* @return field object that represents found field
	* @throws NoSuchFieldException if the field is not found
	*/
	private static Field findField(Object bean, String name) throws NoSuchFieldException {
	return (bean instanceof Class<?>)
	? FieldFinder.findStaticField((Class<?>) bean, name)
	: FieldFinder.findField(bean.getClass(), name);
	}
	}

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