001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.beanutils2;
019
020import java.lang.reflect.InvocationTargetException;
021import java.util.Objects;
022import java.util.function.Predicate;
023
024import org.apache.commons.logging.Log;
025import org.apache.commons.logging.LogFactory;
026
027/**
028 * <p>
029 * {@code Predicate} that evaluates a property value against a specified value.
030 * </p>
031 * <p>
032 * An implementation of {@link java.util.function.Predicate} that evaluates a property value on the object provided against a specified value and returns
033 * {@code true} if equal; {@code false} otherwise. The {@code BeanPropertyValueEqualsPredicate} constructor takes two parameters which determine what property
034 * will be evaluated on the target object and what its expected value should be.
035 * </p>
036 * <dl>
037 * <dt><strong> {@code public BeanPropertyValueEqualsPredicate( String propertyName, Object propertyValue )} </strong></dt>
038 * <dd>Will create a {@code Predicate} that will evaluate the target object and return
039 * {@code true</code> if the property specified by <code>propertyName} has a value which
040 *       is equal to the value specified by {@code propertyValue}. Or return
041 *       {@code false} otherwise.
042 *    </dd>
043 * </dl>
044 * <p>
045 * <strong>Note:</strong> Property names can be a simple, nested, indexed, or mapped property as defined by
046 * {@code org.apache.commons.beanutils2.PropertyUtils}.  If any object in the property path
047 * specified by {@code propertyName</code> is <code>null} then the outcome is based on the
048 * value of the {@code ignoreNull} attribute.
049 * </p>
050 * <p>
051 * A typical usage might look like:
052 * </p>
053 * <pre>{@code
054 * // create the closure
055 * BeanPropertyValueEqualsPredicate predicate =
056 *    new BeanPropertyValueEqualsPredicate( "activeEmployee", Boolean.FALSE );
057 *
058 * // filter the Collection
059 * CollectionUtils.filter( peopleCollection, predicate );
060 * }</pre>
061 * <p>
062 * This would take a {@code Collection} of person objects and filter out any people whose
063 * {@code activeEmployee</code> property is <code>false}. Assuming...
064 * </p>
065 * <ul>
066 *    <li>
067 *       The top level object in the {@code peopleCollection} is an object which represents a
068 *       person.
069 *    </li>
070 *    <li>
071 *       The person object has a {@code getActiveEmployee()} method which returns
072 *       the boolean value for the object's {@code activeEmployee} property.
073 *    </li>
074 * </ul>
075 * <p>
076 * Another typical usage might look like:
077 * </p>
078 * <pre>{@code
079 * // create the closure
080 * BeanPropertyValueEqualsPredicate predicate =
081 *    new BeanPropertyValueEqualsPredicate( "personId", "456-12-1234" );
082 *
083 * // search the Collection
084 * CollectionUtils.find( peopleCollection, predicate );
085 * }</pre>
086 * <p>
087 * This would search a {@code Collection} of person objects and return the first object whose
088 * {@code personId</code> property value equals <code>456-12-1234}. Assuming...
089 * </p>
090 * <ul>
091 * <li>The top level object in the {@code peopleCollection} is an object which represents a person.</li>
092 * <li>The person object has a {@code getPersonId()} method which returns the value for the object's {@code personId} property.</li>
093 * </ul>
094 *
095 * @param <T> The type of the input to the predicate.
096 * @param <V> The property value type.
097 * @see org.apache.commons.beanutils2.PropertyUtils
098 * @see java.util.function.Predicate
099 */
100public class BeanPropertyValueEqualsPredicate<T, V> implements Predicate<T> {
101
102    /** For logging. Each subclass gets its own log instance. */
103    private final Log log = LogFactory.getLog(this.getClass());
104
105    /**
106     * The name of the property which will be evaluated when this {@code Predicate} is executed.
107     */
108    private final String propertyName;
109
110    /**
111     * The value that the property specified by {@code propertyName} will be compared to when this {@code Predicate} executes.
112     */
113    private final V propertyValue;
114
115    /**
116     * <p>
117     * Should {@code null} objects in the property path be ignored?
118     * </p>
119     * <p>
120     * Determines whether {@code null} objects in the property path will generate an
121     * {@code IllegalArgumentException</code> or not. If set to <code>true} then if any objects
122     * in the property path evaluate to {@code null} then the
123     * {@code IllegalArgumentException</code> throw by <code>PropertyUtils} will be logged but
124     * not re-thrown and {@code false</code> will be returned.  If set to <code>false} then if
125     * any objects in the property path evaluate to {@code null} then the
126     * {@code IllegalArgumentException</code> throw by <code>PropertyUtils} will be logged and re-thrown.
127     * </p>
128     */
129    private final boolean ignoreNull;
130
131    /**
132     * 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}.
133     *
134     * @param propertyName  The name of the property that will be evaluated against the expected value.
135     * @param propertyValue The value to use in object evaluation.
136     * @throws IllegalArgumentException If the property name provided is null or empty.
137     */
138    public BeanPropertyValueEqualsPredicate(final String propertyName, final V propertyValue) {
139        this(propertyName, propertyValue, false);
140    }
141
142    /**
143     * Constructor which takes the name of the property, its expected value to be used in evaluation, and a boolean which determines whether {@code null}
144     * objects in the property path will generate an {@code IllegalArgumentException} or not.
145     *
146     * @param propertyName  The name of the property that will be evaluated against the expected value.
147     * @param propertyValue The value to use in object evaluation.
148     * @param ignoreNull    Determines whether {@code null} objects in the property path will generate an {@code IllegalArgumentException} or not.
149     * @throws IllegalArgumentException If the property name provided is null or empty.
150     */
151    public BeanPropertyValueEqualsPredicate(final String propertyName, final V propertyValue, final boolean ignoreNull) {
152        if (propertyName == null || propertyName.isEmpty()) {
153            throw new IllegalArgumentException("propertyName cannot be null or empty");
154        }
155        this.propertyName = propertyName;
156        this.propertyValue = propertyValue;
157        this.ignoreNull = ignoreNull;
158    }
159
160    /**
161     * Utility method which evaluates whether the actual property value equals the expected property value.
162     *
163     * @param expected The expected value.
164     * @param actual   The actual value.
165     * @return True if they are equal; false otherwise.
166     */
167    protected boolean evaluateValue(final V expected, final Object actual) {
168        return Objects.equals(expected, actual);
169    }
170
171    /**
172     * Returns the name of the property which will be evaluated when this {@code Predicate} is executed.
173     *
174     * @return The name of the property which will be evaluated when this {@code Predicate} is executed.
175     */
176    public String getPropertyName() {
177        return propertyName;
178    }
179
180    /**
181     * Returns the value that the property specified by {@code propertyName} will be compared to when this {@code Predicate} executes.
182     *
183     * @return The value that the property specified by {@code propertyName} will be compared to when this {@code Predicate} executes.
184     */
185    public V getPropertyValue() {
186        return propertyValue;
187    }
188
189    /**
190     * Returns the flag which determines whether {@code null} objects in the property path will generate an
191     * {@code IllegalArgumentException</code> or not. If set to <code>true} then
192     * if any objects in the property path evaluate to {@code null} then the
193     * {@code IllegalArgumentException</code> throw by <code>PropertyUtils} will be logged but
194     * not re-thrown and {@code false</code> will be returned.  If set to <code>false} then if
195     * any objects in the property path evaluate to {@code null} then the
196     * {@code IllegalArgumentException</code> throw by <code>PropertyUtils} will be logged and re-thrown.
197     *
198     * @return The flag which determines whether {@code null} objects in the property path will generate an {@code IllegalArgumentException} or not.
199     */
200    public boolean isIgnoreNull() {
201        return ignoreNull;
202    }
203
204    /**
205     * Evaluates the object provided against the criteria specified when this {@code BeanPropertyValueEqualsPredicate} was constructed. Equality is based on
206     * 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
207     * property is {@code null} then the outcome will be based on the value of the {@code ignoreNull} attribute. By default,
208     * {@code ignoreNull</code> is <code>false} and would result in an
209     * {@code IllegalArgumentException} if an object in the property path leading up to the
210     * target property is {@code null}.
211     *
212     * &#64;param object The object to be evaluated.
213     * &#64;return True if the object provided meets all the criteria for this {@code Predicate};
214     * false otherwise.
215     * @throws IllegalArgumentException If an IllegalAccessException, InvocationTargetException, or
216     * NoSuchMethodException is thrown when trying to access the property specified on the object
217     * provided. Or if an object in the property path provided is {@code null} and
218     * {@code ignoreNull</code> is set to <code>false}.
219     */
220    @Override
221    public boolean test(final T object) {
222
223        boolean evaluation = false;
224
225        try {
226            evaluation = evaluateValue(propertyValue, PropertyUtils.getProperty(object, propertyName));
227        } catch (final IllegalArgumentException e) {
228            final String errorMsg = "Problem during evaluation. Null value encountered in property path...";
229
230            if (!ignoreNull) {
231                throw new IllegalArgumentException(errorMsg, e);
232            }
233            log.warn(errorMsg, e);
234        } catch (final IllegalAccessException e) {
235            final String errorMsg = "Unable to access the property provided.";
236            throw new IllegalArgumentException(errorMsg, e);
237        } catch (final InvocationTargetException e) {
238            final String errorMsg = "Exception occurred in property's getter";
239            throw new IllegalArgumentException(errorMsg, e);
240        } catch (final NoSuchMethodException e) {
241            final String errorMsg = "Property not found.";
242            throw new IllegalArgumentException(errorMsg, e);
243        }
244
245        return evaluation;
246    }
247}