/*

 * Copyright (c) 2015, 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.

 */

import java.io.IOException;

import java.net.URL;

import java.util.Enumeration;

import java.lang.System.LoggerFinder;

/**

 * A custom class loader which can hide the registered LoggerProvider

 * depending on the value of a test.logger.hidesProvider system property.

 * @author danielfuchs

 */

public class SystemClassLoader extends ClassLoader {

    final public boolean hidesProvider;

    public SystemClassLoader() {

        hidesProvider = Boolean.getBoolean("test.logger.hidesProvider");

    }

    public SystemClassLoader(ClassLoader parent) {

        super(parent);

        hidesProvider = Boolean.getBoolean("test.logger.hidesProvider");

    }

    boolean accept(String name) {

        final boolean res = !name.endsWith(LoggerFinder.class.getName());

        if (res == false) {

            System.out.println("Hiding " + name);

        }

        return res;

    }

    @Override

    public URL getResource(String name) {

        if (hidesProvider && !accept(name)) {

            return null;

        } else {

            return super.getResource(name);

        }

    }

    class Enumerator implements Enumeration<URL> {

        final Enumeration<URL> enumeration;

        volatile URL next;

        Enumerator(Enumeration<URL> enumeration) {

            this.enumeration = enumeration;

        }

        @Override

        public boolean hasMoreElements() {

            if (next != null) return true;

            if (!enumeration.hasMoreElements()) return false;

            if (hidesProvider == false) return true;

            next = enumeration.nextElement();

            if (accept(next.getPath())) return true;

            next = null;

            return hasMoreElements();

        }

        @Override

        public URL nextElement() {

            final URL res = next == null ? enumeration.nextElement() : next;

            next = null;

            if (hidesProvider == false || accept(res.getPath())) return res;

            return nextElement();

        }

    }

    @Override

    public Enumeration<URL> getResources(String name) throws IOException {

        final Enumeration<URL> enumeration = super.getResources(name);

        return hidesProvider ? new Enumerator(enumeration) : enumeration;

    }

}