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.InvocationTargetException;
20 import java.lang.reflect.Method;
21 import java.util.Objects;
22
23 import org.apache.commons.collections4.FunctorException;
24 import org.apache.commons.collections4.Transformer;
25
26 /**
27 * Transformer 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 InvokerTransformer<I, O> implements Transformer<I, O> {
38
39 /**
40 * Gets an instance of this transformer calling a specific method with no arguments.
41 *
42 * @param <I> the input type
43 * @param <O> the output type
44 * @param methodName the method name to call
45 * @return an invoker transformer
46 * @throws NullPointerException if methodName is null
47 * @since 3.1
48 */
49 public static <I, O> Transformer<I, O> invokerTransformer(final String methodName) {
50 return new InvokerTransformer<>(Objects.requireNonNull(methodName, "methodName"));
51 }
52 /**
53 * Gets an instance of this transformer calling a specific method with specific values.
54 *
55 * @param <I> the input type
56 * @param <O> the output type
57 * @param methodName the method name to call
58 * @param paramTypes the parameter types of the method
59 * @param args the arguments to pass to the method
60 * @return an invoker transformer
61 * @throws NullPointerException if methodName is null
62 * @throws IllegalArgumentException if paramTypes does not match args
63 */
64 public static <I, O> Transformer<I, O> invokerTransformer(final String methodName, final Class<?>[] paramTypes,
65 final Object[] args) {
66 Objects.requireNonNull(methodName, "methodName");
67 if (paramTypes == null && args != null
68 || paramTypes != null && args == null
69 || paramTypes != null && args != null && paramTypes.length != args.length) {
70 throw new IllegalArgumentException("The parameter types must match the arguments");
71 }
72 if (paramTypes == null || paramTypes.length == 0) {
73 return new InvokerTransformer<>(methodName);
74 }
75 return new InvokerTransformer<>(methodName, paramTypes, args);
76 }
77 /** The method name to call */
78 private final String iMethodName;
79
80 /** The array of reflection parameter types */
81 private final Class<?>[] iParamTypes;
82
83 /** The array of reflection arguments */
84 private final Object[] iArgs;
85
86 /**
87 * Constructor for no arg instance.
88 *
89 * @param methodName the method to call
90 */
91 private InvokerTransformer(final String methodName) {
92 iMethodName = methodName;
93 iParamTypes = null;
94 iArgs = null;
95 }
96
97 /**
98 * Constructor that performs no validation.
99 * Use {@code invokerTransformer} if you want that.
100 * <p>
101 * Note: from 4.0, the input parameters will be cloned
102 *
103 * @param methodName the method to call
104 * @param paramTypes the constructor parameter types
105 * @param args the constructor arguments
106 */
107 public InvokerTransformer(final String methodName, final Class<?>[] paramTypes, final Object[] args) {
108 iMethodName = methodName;
109 iParamTypes = paramTypes != null ? paramTypes.clone() : null;
110 iArgs = args != null ? args.clone() : null;
111 }
112
113 /**
114 * Transforms the input to result by invoking a method on the input.
115 *
116 * @param input the input object to transform
117 * @return the transformed result, null if null input
118 */
119 @Override
120 @SuppressWarnings("unchecked")
121 public O transform(final Object input) {
122 if (input == null) {
123 return null;
124 }
125 try {
126 final Class<?> cls = input.getClass();
127 final Method method = cls.getMethod(iMethodName, iParamTypes);
128 return (O) method.invoke(input, iArgs);
129 } catch (final NoSuchMethodException ex) {
130 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
131 input.getClass() + "' does not exist");
132 } catch (final IllegalAccessException ex) {
133 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
134 input.getClass() + "' cannot be accessed");
135 } catch (final InvocationTargetException ex) {
136 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
137 input.getClass() + "' threw an exception", ex);
138 }
139 }
140
141 }