ChildCustomClassLoader.java

/*******************************************************************************
 * Copyright (c) 2001, 2018 IBM Corp. and others
 *
 * This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License 2.0 which accompanies this
 * distribution and is available at https://www.eclipse.org/legal/epl-2.0/
 * or the Apache License, Version 2.0 which accompanies this distribution and
 * is available at https://www.apache.org/licenses/LICENSE-2.0.
 *
 * This Source Code may also be made available under the following
 * Secondary Licenses when the conditions for such availability set
 * forth in the Eclipse Public License, v. 2.0 are satisfied: GNU
 * General Public License, version 2 with the GNU Classpath
 * Exception [1] and GNU General Public License, version 2 with the
 * OpenJDK Assembly Exception [2].
 *
 * [1] https://www.gnu.org/software/classpath/license.html
 * [2] http://openjdk.java.net/legal/assembly-exception.html
 *
 * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 OR GPL-2.0 WITH Classpath-exception-2.0 OR LicenseRef-GPL-2.0 WITH Assembly-exception
 *******************************************************************************/
package com.ibm.j9.jsr292;

import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Helper class loader used in JSR 292 tests for MethodHandles.Lookup API 
 */
public class ChildCustomClassLoader extends ParentCustomClassLoader {

	public ChildCustomClassLoader( ClassLoader parent ) {
		super( parent );
	}
	
	@Override
	public Class<?> loadClass( String className ) throws ClassNotFoundException {
		if ( className.equals( "com.ibm.j9.jsr292.CustomLoadedClass2" ) ) {
			return getClass( className );
		}
		return super.loadClass( className );
	}
	
	private Class<?> getClass( String className )throws ClassNotFoundException {
		String classFile = className.replace(".", "/" )+ ".class";
		try {
			InputStream classStream = getClass().getClassLoader().getResourceAsStream( classFile );
			if ( classStream == null ) {
				throw new ClassNotFoundException( "Error loading class : " + classFile );
			}
	        int size = classStream.available();
	        byte classRep[] = new byte[size];
	        DataInputStream in = new DataInputStream( classStream );
	        in.readFully( classRep );
	        in.close();
	        Class<?> clazz = defineClass( className, classRep, 0, classRep.length );
			return clazz;
		} catch ( IOException e ) {
			throw new ClassNotFoundException( e.getMessage() );
		} 
	}
}