package act.sys;

/*-
 * #%L
 * ACT Framework
 * %%
 * Copyright (C) 2014 - 2019 ActFramework
 * %%
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * #L%
 */

import com.sun.management.GarbageCollectionNotificationInfo;
import com.sun.management.GcInfo;
import org.osgl.$;

import javax.management.Notification;
import javax.management.NotificationEmitter;
import javax.management.NotificationListener;
import javax.management.openmbean.CompositeData;
import java.lang.management.ManagementFactory;
import java.util.List;

public class GcHelper {

    private static volatile List<java.lang.management.GarbageCollectorMXBean> gcBeans;

    static {
        gcBeans = ManagementFactory.getGarbageCollectorMXBeans();
    }

    public static void registerGcEventListener(final $.Visitor<GcInfo> listener) {
        for (java.lang.management.GarbageCollectorMXBean mxBean : gcBeans) {
            NotificationEmitter emitter = (NotificationEmitter) mxBean;
            emitter.addNotificationListener(new NotificationListener() {
                @Override
                public void handleNotification(Notification notification, Object handback) {
                    if (notification.getType().equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) {
                        GarbageCollectionNotificationInfo gcInfo = GarbageCollectionNotificationInfo.from((CompositeData) notification.getUserData());
                        listener.visit(gcInfo.getGcInfo());
                    }
                }
            }, null, null);
        }
    }

}
