/*
* Copyright 2004 Sun Microsystems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package com.sun.syndication.feed.impl;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.io.Serializable;
/**
* Provides deep <b>Bean</b> equals() and hashCode() functionality for Java Beans.
* <p>
* It works on all read/write properties, recursively. It support all primitive types, Strings, Collections,
* bean-like objects and multi-dimensional arrays of any of them.
* <p>
* The hashcode is calculated by getting the hashcode of the Bean String representation.
* <p>
* @author Alejandro Abdelnur
*
*/
public class EqualsBean implements Serializable {
private static final Object[] NO_PARAMS = new Object[0];
private Class _beanClass;
private Object _obj;
/**
* Default constructor.
* <p>
* To be used by classes extending EqualsBean only.
* <p>
* @param beanClass the class/interface to be used for property scanning.
*
*/
protected EqualsBean(Class beanClass) {
_beanClass = beanClass;
_obj = this;
}
/**
* Creates a EqualsBean to be used in a delegation pattern.
* <p>
* For example:
* <p>
* <code>
* public class Foo implements FooI {
* private EqualsBean _equalsBean;
*
* public Foo() {
* _equalsBean = new EqualsBean(FooI.class);
* }
*
* public boolean equals(Object obj) {
* return _equalsBean.beanEquals(obj);
* }
*
* public int hashCode() {
* return _equalsBean.beanHashCode();
* }
*
* }
* </code>
* <p>
* @param beanClass the class/interface to be used for property scanning.
* @param obj object bean to test equality.
*
*/
public EqualsBean(Class beanClass,Object obj) {
if (!beanClass.isInstance(obj)) {
throw new IllegalArgumentException(obj.getClass()+" is not instance of "+beanClass);
}
_beanClass = beanClass;
_obj = obj;
}
/**
* Indicates whether some other object is "equal to" this object as defined by the Object equals() method.
* <p>
* To be used by classes extending EqualsBean. Although it works also for classes using
* EqualsBean in a delegation pattern, for correctness those classes should use the
* @see #beanEquals(Object) beanEquals method.
* <p>
* @param obj he reference object with which to compare.
* @return <b>true</b> if 'this' object is equal to the 'other' object.
*
*/
public boolean equals(Object obj) {
return beanEquals(obj);
}
/**
* Indicates whether some other object is "equal to" the object passed in the constructor,
* as defined by the Object equals() method.
* <p>
* To be used by classes using EqualsBean in a delegation pattern,
* @see #EqualsBean(Class,Object) constructor.
* <p>
* @param obj he reference object with which to compare.
* @return <b>true</b> if the object passed in the constructor is equal to the 'obj' object.
*
*/
public boolean beanEquals(Object obj) {
Object bean1 = _obj;
Object bean2 = obj;
boolean eq;
if (bean2==null) {
eq = false;
}
else
if (bean1==null && bean2==null) {
eq = true;
}
else
if (bean1==null || bean2==null) {
eq = false;
}
else {
if (!_beanClass.isInstance(bean2)) {
eq = false;
}
else {
eq = true;
try {
PropertyDescriptor[] pds = BeanIntrospector.getPropertyDescriptors(_beanClass);
if (pds!=null) {
for (int i = 0; eq && i<pds.length; i++) {
Method pReadMethod = pds[i].getReadMethod();
if (pReadMethod!=null && // ensure it has a getter method
pReadMethod.getDeclaringClass()!=Object.class && // filter Object.class getter methods
pReadMethod.getParameterTypes().length==0) { // filter getter methods that take parameters
Object value1 = pReadMethod.invoke(bean1, NO_PARAMS);
Object value2 = pReadMethod.invoke(bean2, NO_PARAMS);
eq = doEquals(value1, value2);
}
}
}
}
catch (Exception ex) {
throw new RuntimeException("Could not execute equals()", ex);
}
}
}
return eq;
}
/**
* Returns the hashcode for this object.
* <p>
* It follows the contract defined by the Object hashCode() method.
* <p>
* The hashcode is calculated by getting the hashcode of the Bean String representation.
* <p>
* To be used by classes extending EqualsBean. Although it works also for classes using
* EqualsBean in a delegation pattern, for correctness those classes should use the
* @see #beanHashCode() beanHashCode method.
* <p>
* @return the hashcode of the bean object.
*
*/
public int hashCode() {
return beanHashCode();
}
/**
* Returns the hashcode for the object passed in the constructor.
* <p>
* It follows the contract defined by the Object hashCode() method.
* <p>
* The hashcode is calculated by getting the hashcode of the Bean String representation.
* <p>
* To be used by classes using EqualsBean in a delegation pattern,
* @see #EqualsBean(Class,Object) constructor.
* <p>
* @return the hashcode of the bean object.
*
*/
public int beanHashCode() {
return _obj.toString().hashCode();
}
private boolean doEquals(Object obj1, Object obj2) {
boolean eq = obj1==obj2;
if (!eq && obj1!=null && obj2!=null) {
Class classObj1 = obj1.getClass();
Class classObj2 = obj2.getClass();
if (classObj1.isArray() && classObj2.isArray()) {
eq = equalsArray(obj1, obj2);
}
else {
eq = obj1.equals(obj2);
}
}
return eq;
}
private boolean equalsArray(Object array1, Object array2) {
boolean eq;
int length1 = Array.getLength(array1);
int length2 = Array.getLength(array2);
if (length1==length2) {
eq = true;
for (int i = 0; eq && i<length1; i++) {
Object e1 = Array.get(array1, i);
Object e2 = Array.get(array2, i);
eq = doEquals(e1, e2);
}
}
else {
eq = false;
}
return eq;
}
}