test/lib/jdk/test/lib/classloader/FilterClassLoader.java

/*
 * Copyright (c) 2014, 2017, 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 jdk.test.lib.classloader;

import java.util.function.Predicate;
/**
 * A classloader, which using target classloader in case provided condition
 * for class name is met, and using parent otherwise
 */
public class FilterClassLoader extends ClassLoader {

    private final ClassLoader target;
    private final Predicate<String> condition;

    public FilterClassLoader(ClassLoader target, ClassLoader parent,
            Predicate<String> condition) {
        super(parent);
        this.condition = condition;
        this.target = target;
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        if (condition.test(name)) {
            return target.loadClass(name);
        }
        return super.loadClass(name);
    }
}