/*
* 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);
}
}