/*
* 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 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:<field name="TYPE" class="java.lang.Long"/>
is equivalent to 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:<field name="id"><int>0</int></field>
is equivalent to id = 0 in Java code. The following attributes are supported:
- name
- the field name
- class
- the type is used for static fields only
- id
- the identifier of the variable that is intended to store the result
Author: Sergey A. Malenkov Since: 1.7
/**
* 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:
- name
- the field name
- class
- the type is used for static fields only
- id
- the identifier of the variable that is intended to store the result
Params: - name – the attribute name
- value – the attribute value
/**
* 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.
Returns: true if the value of this element should be used as an argument of the element that contained in this one, false otherwise
/**
* 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.
Returns: the context of the field
/**
* 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 name. Params: - name – the name of the field
Returns: the value of the specified field
/**
* 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 name. Params: - name – the name of the field
- value – the new value for the specified field
/**
* 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 name in specified context and returns its value. Params: - bean – the context bean that contains field
- name – the name of the field
Throws: - IllegalAccessException – if the field is not accesible
- NoSuchFieldException – if the field is not found
Returns: the value of the field
/**
* 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 name in specified context and updates its value. Params: - bean – the context bean that contains field
- name – the name of the field
- value – the new value for the field
Throws: - IllegalAccessException – if the field is not accesible
- NoSuchFieldException – if the field is not found
/**
* 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 name in specified context. Params: - bean – the context bean that contains field
- name – the name of the field
Throws: - NoSuchFieldException – if the field is not found
Returns: field object that represents found field
/**
* 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);
}
}