/*

 * 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.

 *

 */

/*

 * @test

 * @bug 4405807

 * @run main/othervm -Xms10m ReferencesTest

 * @summary Verify that references from ResourceBundle cache don't prevent

 * class loader reclamation.

 */

import java.io.File;

import java.lang.ref.WeakReference;

import java.lang.reflect.Field;

import java.net.URL;

import java.net.URLClassLoader;

import java.util.Locale;

import java.util.Map;

import java.util.MissingResourceException;

import java.util.ResourceBundle;

/**

 * This test relies on the current behavior of the garbage collector and is

 * therefore no clear indicator of whether the fix for 4405807 works.

 * If the test fails, it might indicate a regression, or it might just mean

 * that a less aggressive garbage collector is used.

 */

public class ReferencesTest {

    private static final int CLASS_LOADER_COUNT = 20;

    // These two parallel arrays have references to the same class loaders.

    // The weakLoaders array lets us track whether class loaders are being

    // reclaimed after the references in the loaders array are nulled out.

    private static ClassLoader[] loaders = new ClassLoader[CLASS_LOADER_COUNT];

    private static WeakReference[] weakLoaders = new WeakReference[CLASS_LOADER_COUNT];

    public static void main(String[] args) throws Exception {

        URL testDirectory = new File(System.getProperty("test.classes", ".")).toURL();

        for (int i = 0; i < loaders.length; i++) {

            URL[] urls = { testDirectory };

            loaders[i] = new URLClassLoader(urls);

            weakLoaders[i] = new WeakReference(loaders[i]);

        }

        // fill the ResourceBundle cache with entries for half the class loaders

        loadBundles(0, CLASS_LOADER_COUNT / 2);

        report("After loading resource bundles for first half of class loaders: ");

        // release the first half of the class loaders

        for (int i = 0; i < CLASS_LOADER_COUNT / 2; i++) {

            loaders[i] = null;

        }

        System.gc();

        report("After releasing first half of class loaders: ");

        // fill the ResourceBundle cache with entries for second half the class loaders

        loadBundles(CLASS_LOADER_COUNT / 2, CLASS_LOADER_COUNT);

        report("After loading resource bundles for second half of class loaders: ");

        // release the second half of the class loaders

        for (int i = CLASS_LOADER_COUNT / 2; i < CLASS_LOADER_COUNT; i++) {

            loaders[i] = null;

        }

        System.gc();

        report("After releasing second half of class loaders: ");

        // The garbage collector in Tiger actually has reclaimed all class

        // loaders at this point, but in order not to become too dependent

        // on the current behavior, we only require that the first half

        // has been reclaimed.

        if (countLoaders(0, CLASS_LOADER_COUNT / 2) > 0) {

            throw new RuntimeException("Too many class loaders not reclaimed yet.");

        }

    }

    private static void report(String when) throws Exception {

        int first = countLoaders(0, CLASS_LOADER_COUNT / 2);

        int second = countLoaders(CLASS_LOADER_COUNT / 2, CLASS_LOADER_COUNT);

        Class clazz = ResourceBundle.class;

        Field cacheList = clazz.getDeclaredField("cacheList");

        cacheList.setAccessible(true);

        int cacheSize = ((Map)cacheList.get(clazz)).size();

        System.out.println(when);

        System.out.println("    " + first + " loaders alive in first half");

        System.out.println("    " + second + " loaders alive in second half");

        System.out.println("    " + cacheSize + " entries in resource bundle cache");

    }

    private static void loadBundles(int start, int end) throws Exception {

        for (int i = start; i < end; i++) {

            // There's no resource bundle for NonExistantBundle - this

            // let's us test the case where a resource bundle is not found,

            // which in the past created a SoftReference on the value side

            // of the cache.

            try {

                ResourceBundle.getBundle("NonExistantBundle", Locale.US, loaders[i]);

            } catch (MissingResourceException e) {

            }

            // There's a base resource bundle for ReferencesTestBundle - the

            // normal case.

            ResourceBundle.getBundle("ReferencesTestBundle", Locale.US, loaders[i]);

        }

    }

    private static int countLoaders(int start, int end) {

        int count = 0;

        for (int i = start; i < end; i++) {

            if (weakLoaders[i].get() != null) {

                count++;

            }

        }

        return count;

    }

}