//     $Revision: 1.1.2.4 $
package com.kabira.snippets.highavailability;

import com.kabira.platform.ManagedObject;
import com.kabira.platform.Transaction;
import com.kabira.platform.highavailability.Partition;
import com.kabira.platform.highavailability.Partition.State;
import com.kabira.platform.highavailability.PartitionManager;
import com.kabira.platform.highavailability.PartitionNotifier;
import com.kabira.platform.highavailability.ReplicaNode;
import static com.kabira.platform.highavailability.ReplicaNode.ReplicationType.SYNCHRONOUS;

/**
 * Snippet on handling partition state changes.
 * <p>
 * <h2> Target Nodes</h2>
 * <ul>
 * <li> <b>domainnode</b> = A
 * </ul>
 */
public class StateChange
{
    /**
     * Partition state change notifier
     */
    private static class Notifier extends PartitionNotifier
    {
        @Override
        protected void stateChange(String partitionName, State oldState, State newState)
        {
            Partition partition = PartitionManager.getPartition(partitionName);

            String message = "Partition: "
                + partition.getName()
                + " transitioning "
                + "from "
                + oldState
                + " to "
                + newState
                + " now hosted on "
                + partition.getActiveNode();
            System.out.println(message);
        }
    }

    /**
     * Main entry point
     *
     * @param args Not used
     * @throws java.lang.InterruptedException
     */
    public static void main(String[] args) throws InterruptedException
    {
        final Notifier notifier = initialize();

        //
        //    Wait here for operator to shutdown example
        //
        waitForOperator();

        //
        //  Clean up partition notifier
        //
        new Transaction("Remove Partition Notifier")
        {
            @Override
            protected void run() throws Rollback
            {
                ManagedObject.delete(notifier);
            }
        }.execute();
    }

    //
    //  Wait for operator to shutdown example
    //
    private static void waitForOperator()
        throws InterruptedException
    {
        //
        //	Wait until operator requests JVM to exit
        //
        while (true)
        {
            System.out.println("Waiting for operator...");
            Thread.sleep(5000);
        }
    }
    
    private static Notifier initialize()
    {
        return new Transaction("Create Partition Notifier")
        {
            @Override
            protected void run() throws Transaction.Rollback
            {
                m_notifier = new Notifier();

                ReplicaNode[] replicas = new ReplicaNode[]
                {
                    new ReplicaNode("B", SYNCHRONOUS),
                    new ReplicaNode("C", SYNCHRONOUS)
                };
                PartitionManager.definePartition(PARTITION_NAME, null, "A", replicas);

                //
                //  Partition is not enabled - use administration
                //  tools to enable partition
                //
                System.out.println("Enable the " + PARTITION_NAME + " partition.");

                //
                //  Register the partition notifier
                //
                Partition partition = PartitionManager.getPartition(PARTITION_NAME);
                partition.setNotifier(m_notifier);
            }
            
            Notifier initialize()
            {
                execute();
                return m_notifier;
            }
            
            private Notifier m_notifier = null;
        }.initialize();
    }
    
    private static final String PARTITION_NAME = "Notifier Snippet";
}

#
# Partitions enabled on node A.  Partition comes active on A node
#
# administrator servicename=A enable partition name="Notifier Snippet"
#
Partition: Notifier Snippet transitioning from INITIAL to MIGRATING now hosted on A
Partition: Notifier Snippet transitioning from MIGRATING to ACTIVE now hosted on A

#
# Partitions disabled on node A.  Partition fails over to node B
#
# administrator servicename=A disable partition name="Notifier Snippet"
#
Partition: Notifier Snippet transitioning from ACTIVE to MIGRATING now hosted on A
Partition: Notifier Snippet transitioning from MIGRATING to ACTIVE now hosted on B
Partition: Notifier Snippet transitioning from ACTIVE to UNAVAILABLE now hosted on B

#
# Partition restored to node A from node B.
#
# administrator servicename=A define partition name="Notifier Snippet" activenode=A replicas=B,C
# administrator servicename=A display partition name="Notifier Snippet"
#
Partition: Notifier Snippet transitioning from ACTIVE to MIGRATING now hosted on B
Partition: Notifier Snippet transitioning from MIGRATING to ACTIVE now hosted on A