/*
 *  Copyright 2001-2004 The Apache Software Foundation
 *
 *  Licensed 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.collections.functors;

import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.apache.commons.collections.FunctorException;
import org.apache.commons.collections.Transformer;

/**
 * Transformer implementation that creates a new object instance by reflection.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 1.6 $ $Date: 2004/05/16 11:36:31 $
 *
 * @author Stephen Colebourne
 */
public class InvokerTransformer implements Transformer, Serializable {

    /** The serial version */
    static final long serialVersionUID = -8653385846894047688L;
    
    /** 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 instanceof this transformer calling a specific method with specific values.
     * 
     * @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
     */
    public static Transformer getInstance(String methodName, Class[] paramTypes, Object[] args) {
        if (methodName == null) {
            throw new IllegalArgumentException("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);
        } else {
            paramTypes = (Class[]) paramTypes.clone();
            args = (Object[]) args.clone();
            return new InvokerTransformer(methodName, paramTypes, args);
        }
    }

    /**
     * Constructor for no arg instance.
     * 
     * @param methodName  the method to call
     */
    private InvokerTransformer(String methodName) {
        super();
        iMethodName = methodName;
        iParamTypes = null;
        iArgs = null;
    }

    /**
     * Constructor that performs no validation.
     * Use <code>getInstance</code> if you want that.
     * 
     * @param methodName  the method to call
     * @param paramTypes  the constructor parameter types, not cloned
     * @param args  the constructor arguments, not cloned
     */
    public InvokerTransformer(String methodName, Class[] paramTypes, Object[] args) {
        super();
        iMethodName = methodName;
        iParamTypes = paramTypes;
        iArgs = args;
    }

    /**
     * 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
     */
    public Object transform(Object input) {
        if (input == null) {
            return null;
        }
        try {
            Class cls = input.getClass();
            Method method = cls.getMethod(iMethodName, iParamTypes);
            return method.invoke(input, iArgs);
                
        } catch (NoSuchMethodException ex) {
            throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' does not exist");
        } catch (IllegalAccessException ex) {
            throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' cannot be accessed");
        } catch (InvocationTargetException ex) {
            throw new FunctorException("InvokerTransformer: The method '" + iMethodName + "' on '" + input.getClass() + "' threw an exception", ex);
        }
    }

}

@@ -1042,17 +1042,17 @@
 sion: 1.
-6
+7
  $ $Date
@@ -1065,19 +1065,19 @@
 /05/
-16 11:36:31
+26 21:44:05
  $%0A 
@@ -1530,24 +1530,24 @@
 s;%0A%0A    /**%0A
-
      * Gets 
@@ -1557,16 +1557,510 @@
 instance
+ of this transformer calling a specific method with no arguments.%0A     * %0A     * @param methodName  the method name to call%0A     * @return an invoker transformer%0A     * @since Commons Collections 3.1%0A     */%0A    public static Transformer getInstance(String methodName) %7B%0A        if (methodName == null) %7B%0A            throw new IllegalArgumentException(%22The method to invoke must not be null%22);%0A        %7D%0A        return new InvokerTransformer(methodName);%0A    %7D%0A%0A    /**%0A     * Gets an instance 
 of this 

Add additional getInstance method