1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.beanutils2;
19
20 import java.lang.reflect.InvocationTargetException;
21 import java.util.Objects;
22 import java.util.function.Predicate;
23
24 import org.apache.commons.logging.Log;
25 import org.apache.commons.logging.LogFactory;
26
27 /**
28 * <p>
29 * {@code Predicate} that evaluates a property value against a specified value.
30 * </p>
31 * <p>
32 * An implementation of {@link java.util.function.Predicate} that evaluates a property value on the object provided against a specified value and returns
33 * {@code true} if equal; {@code false} otherwise. The {@code BeanPropertyValueEqualsPredicate} constructor takes two parameters which determine what property
34 * will be evaluated on the target object and what its expected value should be.
35 * </p>
36 * <dl>
37 * <dt><strong> {@code public BeanPropertyValueEqualsPredicate( String propertyName, Object propertyValue )} </strong></dt>
38 * <dd>Will create a {@code Predicate} that will evaluate the target object and return
39 * {@code true</code> if the property specified by <code>propertyName} has a value which
40 * is equal to the value specified by {@code propertyValue}. Or return
41 * {@code false} otherwise.
42 * </dd>
43 * </dl>
44 * <p>
45 * <strong>Note:</strong> Property names can be a simple, nested, indexed, or mapped property as defined by
46 * {@code org.apache.commons.beanutils2.PropertyUtils}. If any object in the property path
47 * specified by {@code propertyName</code> is <code>null} then the outcome is based on the
48 * value of the {@code ignoreNull} attribute.
49 * </p>
50 * <p>
51 * A typical usage might look like:
52 * </p>
53 * <pre>{@code
54 * // create the closure
55 * BeanPropertyValueEqualsPredicate predicate =
56 * new BeanPropertyValueEqualsPredicate( "activeEmployee", Boolean.FALSE );
57 *
58 * // filter the Collection
59 * CollectionUtils.filter( peopleCollection, predicate );
60 * }</pre>
61 * <p>
62 * This would take a {@code Collection} of person objects and filter out any people whose
63 * {@code activeEmployee</code> property is <code>false}. Assuming...
64 * </p>
65 * <ul>
66 * <li>
67 * The top level object in the {@code peopleCollection} is an object which represents a
68 * person.
69 * </li>
70 * <li>
71 * The person object has a {@code getActiveEmployee()} method which returns
72 * the boolean value for the object's {@code activeEmployee} property.
73 * </li>
74 * </ul>
75 * <p>
76 * Another typical usage might look like:
77 * </p>
78 * <pre>{@code
79 * // create the closure
80 * BeanPropertyValueEqualsPredicate predicate =
81 * new BeanPropertyValueEqualsPredicate( "personId", "456-12-1234" );
82 *
83 * // search the Collection
84 * CollectionUtils.find( peopleCollection, predicate );
85 * }</pre>
86 * <p>
87 * This would search a {@code Collection} of person objects and return the first object whose
88 * {@code personId</code> property value equals <code>456-12-1234}. Assuming...
89 * </p>
90 * <ul>
91 * <li>The top level object in the {@code peopleCollection} is an object which represents a person.</li>
92 * <li>The person object has a {@code getPersonId()} method which returns the value for the object's {@code personId} property.</li>
93 * </ul>
94 *
95 * @param <T> The type of the input to the predicate.
96 * @param <V> The property value type.
97 * @see org.apache.commons.beanutils2.PropertyUtils
98 * @see java.util.function.Predicate
99 */
100 public 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 * @param object The object to be evaluated.
213 * @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 }