/**************************************************************
 * 
 * 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 util;

import java.lang.reflect.Constructor;

public class DynamicClassLoader {

	/**
	* This method returns a class created by its name
	* created by call to <code>Class.forName()</code>.<p>
	* This method must be overloaded if another loading
	* policy is required for Component and Interface
	* testing classes.
    * @param className The name of the class to create.
    * @return The created class.
	*/
	public static Class forName(String className)
		throws ClassNotFoundException {

		return Class.forName(className) ;
	}

    /**
     * Get an instance of a class. The empty constructor is used.
     * @param className The class to instantiate.
     * @return The instance of the class.
     */
    public Object getInstance(String className)
                                        throws IllegalArgumentException {
        try {
            Class cls = DynamicClassLoader.forName(className);
            return cls.newInstance();
        } catch ( ClassNotFoundException e ) {
            throw new IllegalArgumentException("Couldn't find " + className
                    + " " + e);
        } catch ( IllegalAccessException e ) {
            throw new IllegalArgumentException("Couldn't access " + className
                    + " " + e);
        } catch ( InstantiationException e ) {
            throw new IllegalArgumentException("Couldn't instantiate " +
                            className + " " + e);
        }
    }

    /**
     * Get an instance of a class. The constructor matching to the 
     * arguments is used and the arguments are given to this constructor.
     * @param className The class to instantiate.
     * @param ctorArgs Arguments for the constructor.
     * @return The instance of the class.
     */
    public Object getInstance(String className, Object[] ctorArgs)
                                        throws IllegalArgumentException {
        Class[] ctorType = new Class[ctorArgs.length];
        for(int i=0; i<ctorType.length; i++) {
            ctorType[i] = ctorArgs[i].getClass();
        }
        return getInstance(className, ctorType, ctorArgs);
        
    }
    
    /**
     * Get an instance of a class. The constructor matching to the 
     * given calss types is used and the instance is created using the arguments 
     * for the constructor.
     * @param className The class to instantiate.
     * @param ctorClassTypes The class types matching to the constructor.
     * @param ctorArgs Arguments for the constructor.
     * @return The instance of the class.
     */
    public Object getInstance(String className, Class[]ctorClassTypes, Object[] ctorArgs)
                                        throws IllegalArgumentException {
        try {
            Class cls = DynamicClassLoader.forName(className);
            Constructor ctor = cls.getConstructor(ctorClassTypes);
            System.out.println("ctor: " + ctor.getName() +  "  " + ctor.getModifiers());
            
            return ctor.newInstance(ctorArgs);
        } catch ( ClassNotFoundException e ) {
            throw new IllegalArgumentException("Couldn't find " + className
                    + " " + e);
        } catch ( IllegalAccessException e ) {
            throw new IllegalArgumentException("Couldn't access " + className
                    + " " + e);
        } catch ( NoSuchMethodException e ) {
            throw new IllegalArgumentException("Couldn't find constructor for " + className
                    + " " + e);
        } catch ( java.lang.reflect.InvocationTargetException e ) {
            e.printStackTrace();
            throw new IllegalArgumentException("Couldn't invoke " +
                            className + " " + e);
        } catch ( InstantiationException e ) {
            throw new IllegalArgumentException("Couldn't instantiate " +
                            className + " " + e);
        }
    }
}