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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.collections4.functors;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import org.apache.commons.collections4.FunctorException;
import org.apache.commons.collections4.Transformer;
/**
* Transformer implementation that creates a new object instance by reflection.
*
* WARNING: from v4.1 onwards this class will not be serializable anymore
* in order to prevent potential remote code execution exploits. Please refer to
* COLLECTIONS-580
* for more details.
*
* @since 3.0
*/
public class InvokerTransformer implements Transformer {
/** The method name to call */
private final String iMethodName;
/** The array of reflection parameter types */
private final Class[] iParamTypes;
/** The array of reflection arguments */
private final Object[] iArgs;
/**
* Gets an instance of this transformer calling a specific method with no arguments.
*
* @param the input type
* @param the output type
* @param methodName the method name to call
* @return an invoker transformer
* @throws NullPointerException if methodName is null
* @since 3.1
*/
public static Transformer invokerTransformer(final String methodName) {
if (methodName == null) {
throw new NullPointerException("The method to invoke must not be null");
}
return new InvokerTransformer<>(methodName);
}
/**
* Gets an instance of this transformer calling a specific method with specific values.
*
* @param the input type
* @param the output type
* @param methodName the method name to call
* @param paramTypes the parameter types of the method
* @param args the arguments to pass to the method
* @return an invoker transformer
* @throws NullPointerException if methodName is null
* @throws IllegalArgumentException if paramTypes does not match args
*/
public static Transformer invokerTransformer(final String methodName, final Class[] paramTypes,
final Object[] args) {
if (methodName == null) {
throw new NullPointerException("The method to invoke must not be null");
}
if (((paramTypes == null) && (args != null))
|| ((paramTypes != null) && (args == null))
|| ((paramTypes != null) && (args != null) && (paramTypes.length != args.length))) {
throw new IllegalArgumentException("The parameter types must match the arguments");
}
if (paramTypes == null || paramTypes.length == 0) {
return new InvokerTransformer<>(methodName);
}
return new InvokerTransformer<>(methodName, paramTypes, args);
}
/**
* Constructor for no arg instance.
*
* @param methodName the method to call
*/
private InvokerTransformer(final String methodName) {
super();
iMethodName = methodName;
iParamTypes = null;
iArgs = null;
}
/**
* Constructor that performs no validation.
* Use invokerTransformer if you want that.
*
* Note: from 4.0, the input parameters will be cloned
*
* @param methodName the method to call
* @param paramTypes the constructor parameter types
* @param args the constructor arguments
*/
public InvokerTransformer(final String methodName, final Class[] paramTypes, final Object[] args) {
super();
iMethodName = methodName;
iParamTypes = paramTypes != null ? paramTypes.clone() : null;
iArgs = args != null ? args.clone() : null;
}
/**
* Transforms the input to result by invoking a method on the input.
*
* @param input the input object to transform
* @return the transformed result, null if null input
*/
@Override
@SuppressWarnings("unchecked")
public O transform(final Object input) {
if (input == null) {
return null;
}
try {
final Class cls = input.getClass();
final Method method = cls.getMethod(iMethodName, iParamTypes);
return (O) method.invoke(input, iArgs);
} catch (final NoSuchMethodException ex) {
throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
input.getClass() + "' does not exist");
} catch (final IllegalAccessException ex) {
throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
input.getClass() + "' cannot be accessed");
} catch (final InvocationTargetException ex) {
throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" +
input.getClass() + "' threw an exception", ex);
}
}
}