/*******************************************************************************
 * Copyright (c) 2011, 2015 Rüdiger Herrmann and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Rüdiger Herrmann - initial API and implementation
 *    Frank Appel - improved exception handling (bug 340482)
 *    EclipseSource - bug 348056: Eliminate compiler warnings
 ******************************************************************************/
package org.eclipse.rap.rwt.internal.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;


public final class ClassUtil {

  public static Object newInstance( ClassLoader classLoader, String className ) {
    ParamCheck.notNull( className, "className" );
    ParamCheck.notNull( classLoader, "classLoader" );
    try {
      return newInstance( classLoader.loadClass( className ) );
    } catch( ClassNotFoundException cnfe ) {
      throw new ClassInstantiationException( "Failed to load type: " + className, cnfe );
    }
  }

  public static <T> T newInstance( Class<T> type ) {
    return newInstance( type, null, null );
  }

  public static <T> T newInstance( Class<T> type, Class<?>[] paramTypes, Object[] paramValues ) {
    ParamCheck.notNull( type, "type" );
    try {
      return createInstance( type, paramTypes, paramValues );
    } catch( RuntimeException rte ) {
      throw rte;
    } catch( InvocationTargetException ite ) {
      rethrowRuntimeExceptions( ite );
      throwInstantiationException( type, ite.getCause() );
    } catch( Exception exception ) {
      throwInstantiationException( type, exception );
    }
    return null;
  }

  private static <T> T createInstance( Class<T> type, Class<?>[] paramTypes, Object[] paramValues )
    throws Exception
  {
    Constructor<T> constructor = type.getDeclaredConstructor( paramTypes );
    if( !constructor.isAccessible() ) {
      constructor.setAccessible( true );
    }
    return constructor.newInstance( paramValues );
  }

  private static void rethrowRuntimeExceptions( InvocationTargetException ite ) {
    if( ite.getCause() instanceof RuntimeException ) {
      throw ( RuntimeException )ite.getCause();
    }
  }

  private static void throwInstantiationException( Class<?> type, Throwable cause ) {
    String msg = "Failed to create instance of type: " + type.getName();
    throw new ClassInstantiationException( msg, cause );
  }

  private ClassUtil() {
    // prevent instantiation
  }

}