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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.commons.beanutils;

import org.apache.commons.collections.Predicate;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.lang.reflect.InvocationTargetException;


/**
 * 

Predicate that evaluates a property value against a specified value.

*

* An implementation of org.apache.commons.collections.Predicate that evaluates a * property value on the object provided against a specified value and returns true * if equal; false otherwise. * The BeanPropertyValueEqualsPredicate constructor takes two parameters which * determine what property will be evaluated on the target object and what its expected value should * be. *

*
* *
public BeanPropertyValueEqualsPredicate( String propertyName, Object propertyValue )
*
*
*
* Will create a Predicate that will evaluate the target object and return * true if the property specified by propertyName has a value which * is equal to the the value specified by propertyValue. Or return * false otherwise. *
*
*

*

* Note: Property names can be a simple, nested, indexed, or mapped property as defined by * org.apache.commons.beanutils.PropertyUtils. If any object in the property path * specified by propertyName is null then the outcome is based on the * value of the ignoreNull attribute. *

*

* A typical usage might look like: *

 * // create the closure
 * BeanPropertyValueEqualsPredicate predicate =
 *    new BeanPropertyValueEqualsPredicate( "activeEmployee", Boolean.FALSE );
 *
 * // filter the Collection
 * CollectionUtils.filter( peopleCollection, predicate );
 * 
*

*

* This would take a Collection of person objects and filter out any people whose * activeEmployee property is false. Assuming... *

    *
  • * The top level object in the peeopleCollection is an object which represents a * person. *
  • *
  • * The person object has a getActiveEmployee() method which returns * the boolean value for the object's activeEmployee property. *
  • *
*

*

* Another typical usage might look like: *

 * // create the closure
 * BeanPropertyValueEqualsPredicate predicate =
 *    new BeanPropertyValueEqualsPredicate( "personId", "456-12-1234" );
 *
 * // search the Collection
 * CollectionUtils.find( peopleCollection, predicate );
 * 
*

*

* This would search a Collection of person objects and return the first object whose * personId property value equals 456-12-1234. Assuming... *

    *
  • * The top level object in the peeopleCollection is an object which represents a * person. *
  • *
  • * The person object has a getPersonId() method which returns * the value for the object's personId property. *
  • *
*

* * @author Norm Deane * @see org.apache.commons.beanutils.PropertyUtils * @see org.apache.commons.collections.Predicate */ public class BeanPropertyValueEqualsPredicate implements Predicate { /** For logging. */ private final Log log = LogFactory.getLog(this.getClass()); /** * The name of the property which will be evaluated when this Predicate is executed. */ private String propertyName; /** * The value that the property specified by propertyName * will be compared to when this Predicate executes. */ private Object propertyValue; /** *

Should null objects in the property path be ignored?

*

* Determines whether null objects in the property path will genenerate an * IllegalArgumentException or not. If set to true then if any objects * in the property path evaluate to null then the * IllegalArgumentException throw by PropertyUtils will be logged but * not rethrown and false will be returned. If set to false then if * any objects in the property path evaluate to null then the * IllegalArgumentException throw by PropertyUtils will be logged and * rethrown. *

*/ private boolean ignoreNull; /** * Constructor which takes the name of the property, its expected value to be used in evaluation, * and assumes ignoreNull to be false. * * @param propertyName The name of the property that will be evaluated against the expected value. * @param propertyValue The value to use in object evaluation. * @throws IllegalArgumentException If the property name provided is null or empty. */ public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue) { this(propertyName, propertyValue, false); } /** * Constructor which takes the name of the property, its expected value * to be used in evaluation, and a boolean which determines whether null objects in * the property path will genenerate an IllegalArgumentException or not. * * @param propertyName The name of the property that will be evaluated against the expected value. * @param propertyValue The value to use in object evaluation. * @param ignoreNull Determines whether null objects in the property path will * genenerate an IllegalArgumentException or not. * @throws IllegalArgumentException If the property name provided is null or empty. */ public BeanPropertyValueEqualsPredicate(String propertyName, Object propertyValue, boolean ignoreNull) { super(); if ((propertyName != null) && (propertyName.length() > 0)) { this.propertyName = propertyName; this.propertyValue = propertyValue; this.ignoreNull = ignoreNull; } else { throw new IllegalArgumentException("propertyName cannot be null or empty"); } } /** * Evaulates the object provided against the criteria specified when this * BeanPropertyValueEqualsPredicate was constructed. Equality is based on * either reference or logical equality as defined by the property object's equals method. If * any object in the property path leading up to the target property is null then * the outcome will be based on the value of the ignoreNull attribute. By default, * ignoreNull is false and would result in an * IllegalArgumentException if an object in the property path leading up to the * target property is null. * * @param object The object to be evaluated. * @return True if the object provided meets all the criteria for this Predicate; * false otherwise. * @throws IllegalArgumentException If an IllegalAccessException, InvocationTargetException, or * NoSuchMethodException is thrown when trying to access the property specified on the object * provided. Or if an object in the property path provided is null and * ignoreNull is set to false. */ public boolean evaluate(Object object) { boolean evaluation = false; try { evaluation = evaluateValue(propertyValue, PropertyUtils.getProperty(object, propertyName)); } catch (IllegalArgumentException e) { final String errorMsg = "Problem during evaluation. Null value encountered in property path..."; if (ignoreNull) { log.warn("WARNING: " + errorMsg + e); } else { IllegalArgumentException iae = new IllegalArgumentException(errorMsg); if (!BeanUtils.initCause(iae, e)) { log.error(errorMsg, e); } throw iae; } } catch (IllegalAccessException e) { final String errorMsg = "Unable to access the property provided."; IllegalArgumentException iae = new IllegalArgumentException(errorMsg); if (!BeanUtils.initCause(iae, e)) { log.error(errorMsg, e); } throw iae; } catch (InvocationTargetException e) { final String errorMsg = "Exception occurred in property's getter"; IllegalArgumentException iae = new IllegalArgumentException(errorMsg); if (!BeanUtils.initCause(iae, e)) { log.error(errorMsg, e); } throw iae; } catch (NoSuchMethodException e) { final String errorMsg = "Property not found."; IllegalArgumentException iae = new IllegalArgumentException(errorMsg); if (!BeanUtils.initCause(iae, e)) { log.error(errorMsg, e); } throw iae; } return evaluation; } /** * Utility method which evaluates whether the actual property value equals the expected property * value. * * @param expected The expected value. * @param actual The actual value. * @return True if they are equal; false otherwise. */ private boolean evaluateValue(Object expected, Object actual) { return (expected == actual) || ((expected != null) && expected.equals(actual)); } /** * Returns the name of the property which will be evaluated when this Predicate is * executed. * * @return The name of the property which will be evaluated when this Predicate is * executed. */ public String getPropertyName() { return propertyName; } /** * Returns the value that the property specified by propertyName will be compared to * when this Predicate executes. * * @return The value that the property specified by propertyName will be compared to * when this Predicate executes. */ public Object getPropertyValue() { return propertyValue; } /** * Returns the flag which determines whether null objects in the property path will * genenerate an IllegalArgumentException or not. If set to true then * if any objects in the property path evaluate to null then the * IllegalArgumentException throw by PropertyUtils will be logged but * not rethrown and false will be returned. If set to false then if * any objects in the property path evaluate to null then the * IllegalArgumentException throw by PropertyUtils will be logged and * rethrown. * * @return The flag which determines whether null objects in the property path will * genenerate an IllegalArgumentException or not. */ public boolean isIgnoreNull() { return ignoreNull; } }