HzHealthCheckExample.java

/*
 * Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
 *
 * 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.
 */

package com.hazelcast.test;

import com.hazelcast.client.HazelcastClient;
import com.hazelcast.client.config.ClientConfig;
import com.hazelcast.cluster.ClusterState;
import com.hazelcast.core.*;

import java.io.Serializable;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

public class MainClient {


    public static void main(String[] args) throws InterruptedException, ExecutionException {
        final HazelcastInstance instance1 = Hazelcast.newHazelcastInstance();
        final HazelcastInstance instance2 = Hazelcast.newHazelcastInstance();
        ClientConfig config = new ClientConfig();
        HazelcastInstance client = HazelcastClient.newHazelcastClient(config);
        IExecutorService s = client.getExecutorService("s");

        for (int i = 0; i < 1000; i++) {
            Thread.sleep(1000);
            Future f = s.submit(new HealthChecker());
            System.out.println("state:"+ f.get());
        }
    }

    static class HealthChecker implements HazelcastInstanceAware, Callable, Serializable {
        HazelcastInstance instance;

        public void setHazelcastInstance(HazelcastInstance hazelcastInstance) {
            instance = hazelcastInstance;
        }

        public Boolean call() throws Exception {
            System.out.println("cluster state:" + instance.getCluster().getClusterState());
            // check if cluster is in active and running state
            if(!instance.getCluster().getClusterState().equals(ClusterState.ACTIVE)) {
                return false;
            }

            System.out.println("is member safe:" + instance.getPartitionService().isLocalMemberSafe());
            // check if member is safe, namely all migrations are complete. no data will lost if the member is killed
            if(!instance.getPartitionService().isLocalMemberSafe()) {
                return false;
            }

            System.out.println("is cluster safe:" + instance.getPartitionService().isClusterSafe());
            // check if cluster is safe, namely all migrations are complete cluster-wide. no data will lost if any member is killed
            if(!instance.getPartitionService().isClusterSafe()) {
                return false;
            }

            // you can also check the cluster size and return false if it is below x
            int clusterSize = instance.getCluster().getMembers().size();
            System.out.println("cluster size:" + clusterSize);

            // you can also check the client count and return false if it is below x
            int numberOfClients = instance.getClientService().getConnectedClients().size();
            System.out.println("number of Clients:" + numberOfClients);


            return true;
        }
    }


}