/*

 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.oracle.java.testlibrary;

import java.security.SecureClassLoader;

/**

 * {@code ByteCodeLoader} can be used for easy loading of byte code already

 * present in memory.

 *

 * {@code InMemoryCompiler} can be used for compiling source code in a string

 * into byte code, which then can be loaded with {@code ByteCodeLoader}.

 *

 * @see InMemoryCompiler

 */

public class ByteCodeLoader extends SecureClassLoader {

    private final String className;

    private final byte[] byteCode;

    /**

     * Creates a new {@code ByteCodeLoader} ready to load a class with the

     * given name and the given byte code.

     *

     * @param className The name of the class

     * @param byteCode The byte code of the class

     */

    public ByteCodeLoader(String className, byte[] byteCode) {

        this.className = className;

        this.byteCode = byteCode;

    }

    @Override

    protected Class<?> findClass(String name) throws ClassNotFoundException {

        if (!name.equals(className)) {

            throw new ClassNotFoundException(name);

        }

        return defineClass(name, byteCode, 0, byteCode.length);

    }

    /**

     * Utility method for creating a new {@code ByteCodeLoader} and then

     * directly load the given byte code.

     *

     * @param className The name of the class

     * @param byteCode The byte code for the class

     * @throws ClassNotFoundException if the class can't be loaded

     * @return A {@see Class} object representing the class

     */

    public static Class<?> load(String className, byte[] byteCode) throws ClassNotFoundException {

        return new ByteCodeLoader(className, byteCode).loadClass(className);

    }

}