/*

  * 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;

 /**

  * <p><code>Predicate</code> that evaluates a property value against a specified value.</p>

  * <p>

  * An implementation of <code>org.apache.commons.collections.Predicate</code> that evaluates a

  * property value on the object provided against a specified value and returns <code>true</code>

  * if equal; <code>false</code> otherwise.

  * The <code>BeanPropertyValueEqualsPredicate</code> constructor takes two parameters which

  * determine what property will be evaluated on the target object and what its expected value should

  * be.

  * <dl>

  *    <dt>

  *       <strong><code>

  *           <pre>public BeanPropertyValueEqualsPredicate( String propertyName, Object propertyValue )</pre>

  *       </code></strong>

  *    </dt>

  *    <dd>

  *       Will create a <code>Predicate</code> that will evaluate the target object and return

  *       <code>true</code> if the property specified by <code>propertyName</code> has a value which

  *       is equal to the the value specified by <code>propertyValue</code>. Or return

  *       <code>false</code> otherwise.

  *    </dd>

  * </dl>

  * </p>

  * <p>

  * <strong>Note:</strong> Property names can be a simple, nested, indexed, or mapped property as defined by

  * <code>org.apache.commons.beanutils.PropertyUtils</code>.  If any object in the property path

  * specified by <code>propertyName</code> is <code>null</code> then the outcome is based on the

  * value of the <code>ignoreNull</code> attribute.

  * </p>

  * <p>

  * A typical usage might look like:

  * <code><pre>

  * // create the closure

  * BeanPropertyValueEqualsPredicate predicate =

  *    new BeanPropertyValueEqualsPredicate( "activeEmployee", Boolean.FALSE );

  *

  * // filter the Collection

  * CollectionUtils.filter( peopleCollection, predicate );

  * </pre></code>

  * </p>

  * <p>

  * This would take a <code>Collection</code> of person objects and filter out any people whose

  * <code>activeEmployee</code> property is <code>false</code>. Assuming...

  * <ul>

  *    <li>

  *       The top level object in the <code>peeopleCollection</code> is an object which represents a

  *       person.

  *    </li>

  *    <li>

  *       The person object has a <code>getActiveEmployee()</code> method which returns

  *       the boolean value for the object's <code>activeEmployee</code> property.

  *    </li>

  * </ul>

  * </p>

  * <p>

  * Another typical usage might look like:

  * <code><pre>

  * // create the closure

  * BeanPropertyValueEqualsPredicate predicate =

  *    new BeanPropertyValueEqualsPredicate( "personId", "456-12-1234" );

  *

  * // search the Collection

  * CollectionUtils.find( peopleCollection, predicate );

  * </pre><code>

  * </p>

  * <p>

  * This would search a <code>Collection</code> of person objects and return the first object whose

  * <code>personId</code> property value equals <code>456-12-1234</code>. Assuming...

  * <ul>

  *    <li>

  *       The top level object in the <code>peeopleCollection</code> is an object which represents a

  *       person.

  *    </li>

  *    <li>

  *       The person object has a <code>getPersonId()</code> method which returns

  *       the value for the object's <code>personId</code> property.

  *    </li>

  * </ul>

  * </p>

  *

  * @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 <code>Predicate</code> is executed.

      */

     private String propertyName;

     /**

      * The value that the property specified by <code>propertyName</code>

      * will be compared to when this <code>Predicate</code> executes.

      */

     private Object propertyValue;

     /**

      * <p>Should <code>null</code> objects in the property path be ignored?</p>

      * <p>

      * Determines whether <code>null</code> objects in the property path will genenerate an

      * <code>IllegalArgumentException</code> or not. If set to <code>true</code> then if any objects

      * in the property path evaluate to <code>null</code> then the

      * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged but

      * not rethrown and <code>false</code> will be returned.  If set to <code>false</code> then if

      * any objects in the property path evaluate to <code>null</code> then the

      * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged and

      * rethrown.

      * </p>

      */

     private boolean ignoreNull;

     /**

      * Constructor which takes the name of the property, its expected value to be used in evaluation,

      * and assumes <code>ignoreNull</code> to be <code>false</code>.

      *

      * @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 <code>null</code> objects in

      * the property path will genenerate an <code>IllegalArgumentException</code> 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 <code>null</code> objects in the property path will

      * genenerate an <code>IllegalArgumentException</code> 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

      * <code>BeanPropertyValueEqualsPredicate</code> 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 <code>null</code> then

      * the outcome will be based on the value of the <code>ignoreNull</code> attribute. By default,

      * <code>ignoreNull</code> is <code>false</code> and would result in an

      * <code>IllegalArgumentException</code> if an object in the property path leading up to the

      * target property is <code>null</code>.

      *

      * @param object The object to be evaluated.

      * @return True if the object provided meets all the criteria for this <code>Predicate</code>;

      * 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 <code>null</code> and

      * <code>ignoreNull</code> is set to <code>false</code>.

      */

     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.

      */

     protected 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 <code>Predicate</code> is

      * executed.

      *

      * @return The name of the property which will be evaluated when this <code>Predicate</code> is

      * executed.

      */

     public String getPropertyName() {

         return propertyName;

     }

     /**

      * Returns the value that the property specified by <code>propertyName</code> will be compared to

      * when this <code>Predicate</code> executes.

      *

      * @return The value that the property specified by <code>propertyName</code> will be compared to

      * when this <code>Predicate</code> executes.

      */

     public Object getPropertyValue() {

         return propertyValue;

     }

     /**

      * Returns the flag which determines whether <code>null</code> objects in the property path will

      * genenerate an <code>IllegalArgumentException</code> or not. If set to <code>true</code> then

      * if any objects in the property path evaluate to <code>null</code> then the

      * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged but

      * not rethrown and <code>false</code> will be returned.  If set to <code>false</code> then if

      * any objects in the property path evaluate to <code>null</code> then the

      * <code>IllegalArgumentException</code> throw by <code>PropertyUtils</code> will be logged and

      * rethrown.

      *

      * @return The flag which determines whether <code>null</code> objects in the property path will

      * genenerate an <code>IllegalArgumentException</code> or not.

      */

     public boolean isIgnoreNull() {

         return ignoreNull;

     }

 }