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 * <strong>WARNING:</strong> from v4.1 onwards this class will <strong>not</strong> 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 * @param <T> the type of the input to the function.
36 * @param <R> the type of the result of the function.
37 * @since 3.0
38 */
39 public class InvokerTransformer<T, R> implements Transformer<T, R> {
40
41 /**
42 * Gets an instance of this transformer calling a specific method with no arguments.
43 *
44 * @param <I> the input type
45 * @param <O> the output type
46 * @param methodName the method name to call
47 * @return an invoker transformer
48 * @throws NullPointerException if methodName is null
49 * @since 3.1
50 */
51 public static <I, O> Transformer<I, O> invokerTransformer(final String methodName) {
52 return new InvokerTransformer<>(Objects.requireNonNull(methodName, "methodName"));
53 }
54 /**
55 * Gets an instance of this transformer calling a specific method with specific values.
56 *
57 * @param <I> the input type
58 * @param <O> the output type
59 * @param methodName the method name to call
60 * @param paramTypes the parameter types of the method
61 * @param args the arguments to pass to the method
62 * @return an invoker transformer
63 * @throws NullPointerException if methodName is null
64 * @throws IllegalArgumentException if paramTypes does not match args
65 */
66 public static <I, O> Transformer<I, O> invokerTransformer(final String methodName, final Class<?>[] paramTypes,
67 final Object[] args) {
68 Objects.requireNonNull(methodName, "methodName");
69 if (paramTypes == null && args != null
70 || paramTypes != null && args == null
71 || paramTypes != null && args != null && paramTypes.length != args.length) {
72 throw new IllegalArgumentException("The parameter types must match the arguments");
73 }
74 if (paramTypes == null || paramTypes.length == 0) {
75 return new InvokerTransformer<>(methodName);
76 }
77 return new InvokerTransformer<>(methodName, paramTypes, args);
78 }
79 /** The method name to call */
80 private final String iMethodName;
81
82 /** The array of reflection parameter types */
83 private final Class<?>[] iParamTypes;
84
85 /** The array of reflection arguments */
86 private final Object[] iArgs;
87
88 /**
89 * Constructor for no arg instance.
90 *
91 * @param methodName the method to call
92 */
93 private InvokerTransformer(final String methodName) {
94 iMethodName = methodName;
95 iParamTypes = null;
96 iArgs = null;
97 }
98
99 /**
100 * Constructor that performs no validation.
101 * Use {@code invokerTransformer} if you want that.
102 * <p>
103 * Note: from 4.0, the input parameters will be cloned
104 *
105 * @param methodName the method to call
106 * @param paramTypes the constructor parameter types
107 * @param args the constructor arguments
108 */
109 public InvokerTransformer(final String methodName, final Class<?>[] paramTypes, final Object[] args) {
110 iMethodName = methodName;
111 iParamTypes = paramTypes != null ? paramTypes.clone() : null;
112 iArgs = args != null ? args.clone() : null;
113 }
114
115 /**
116 * Transforms the input to result by invoking a method on the input.
117 *
118 * @param input the input object to transform
119 * @return the transformed result, null if null input
120 */
121 @Override
122 @SuppressWarnings("unchecked")
123 public R transform(final Object input) {
124 if (input == null) {
125 return null;
126 }
127 try {
128 final Class<?> cls = input.getClass();
129 final Method method = cls.getMethod(iMethodName, iParamTypes);
130 return (R) method.invoke(input, iArgs);
131 } catch (final NoSuchMethodException ex) {
132 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
133 input.getClass() + "' does not exist");
134 } catch (final IllegalAccessException ex) {
135 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
136 input.getClass() + "' cannot be accessed");
137 } catch (final InvocationTargetException ex) {
138 throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
139 input.getClass() + "' threw an exception", ex);
140 }
141 }
142
143 }