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 package org.apache.commons.collections4.functors;
18
19 import java.lang.reflect.Constructor;
20 import java.lang.reflect.InvocationTargetException;
21 import java.util.Objects;
22
23 import org.apache.commons.collections4.Factory;
24 import org.apache.commons.collections4.FunctorException;
25
26 /**
27 * Factory implementation that creates a new object instance by reflection.
28 * <p>
29 * <b>WARNING:</b> from v4.1 onwards this class will <b>not</b> be serializable anymore
30 * in order to prevent potential remote code execution exploits. Please refer to
31 * <a href="https://issues.apache.org/jira/browse/COLLECTIONS-580">COLLECTIONS-580</a>
32 * for more details.
33 * </p>
34 *
35 * @since 3.0
36 */
37 public class InstantiateFactory<T> implements Factory<T> {
38
39 /**
40 * Factory method that performs validation.
41 *
42 * @param <T> the type the factory creates
43 * @param classToInstantiate the class to instantiate, not null
44 * @param paramTypes the constructor parameter types, cloned
45 * @param args the constructor arguments, cloned
46 * @return a new instantiate factory
47 * @throws NullPointerException if classToInstantiate is null
48 * @throws IllegalArgumentException if paramTypes does not match args
49 */
50 public static <T> Factory<T> instantiateFactory(final Class<T> classToInstantiate,
51 final Class<?>[] paramTypes,
52 final Object[] args) {
53 Objects.requireNonNull(classToInstantiate, "classToInstantiate");
54 if (paramTypes == null && args != null
55 || paramTypes != null && args == null
56 || paramTypes != null && args != null && paramTypes.length != args.length) {
57 throw new IllegalArgumentException("Parameter types must match the arguments");
58 }
59
60 if (paramTypes == null || paramTypes.length == 0) {
61 return new InstantiateFactory<>(classToInstantiate);
62 }
63 return new InstantiateFactory<>(classToInstantiate, paramTypes, args);
64 }
65 /** The class to create */
66 private final Class<T> iClassToInstantiate;
67 /** The constructor parameter types */
68 private final Class<?>[] iParamTypes;
69 /** The constructor arguments */
70 private final Object[] iArgs;
71
72 /** The constructor */
73 private transient Constructor<T> iConstructor;
74
75 /**
76 * Constructor that performs no validation.
77 * Use {@code instantiateFactory} if you want that.
78 *
79 * @param classToInstantiate the class to instantiate
80 */
81 public InstantiateFactory(final Class<T> classToInstantiate) {
82 iClassToInstantiate = classToInstantiate;
83 iParamTypes = null;
84 iArgs = null;
85 findConstructor();
86 }
87
88 /**
89 * Constructor that performs no validation.
90 * Use {@code instantiateFactory} if you want that.
91 *
92 * @param classToInstantiate the class to instantiate
93 * @param paramTypes the constructor parameter types, cloned
94 * @param args the constructor arguments, cloned
95 */
96 public InstantiateFactory(final Class<T> classToInstantiate, final Class<?>[] paramTypes, final Object[] args) {
97 iClassToInstantiate = classToInstantiate;
98 iParamTypes = paramTypes.clone();
99 iArgs = args.clone();
100 findConstructor();
101 }
102
103 /**
104 * Creates an object using the stored constructor.
105 *
106 * @return the new object
107 */
108 @Override
109 public T create() {
110 // needed for post-serialization
111 if (iConstructor == null) {
112 findConstructor();
113 }
114
115 try {
116 return iConstructor.newInstance(iArgs);
117 } catch (final InstantiationException ex) {
118 throw new FunctorException("InstantiateFactory: InstantiationException", ex);
119 } catch (final IllegalAccessException ex) {
120 throw new FunctorException("InstantiateFactory: Constructor must be public", ex);
121 } catch (final InvocationTargetException ex) {
122 throw new FunctorException("InstantiateFactory: Constructor threw an exception", ex);
123 }
124 }
125
126 /**
127 * Find the Constructor for the class specified.
128 */
129 private void findConstructor() {
130 try {
131 iConstructor = iClassToInstantiate.getConstructor(iParamTypes);
132 } catch (final NoSuchMethodException ex) {
133 throw new IllegalArgumentException("InstantiateFactory: The constructor must exist and be public ");
134 }
135 }
136
137 }