testing.Control

package testing;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.jgroups.Address;
import org.jgroups.JChannel;
import org.jgroups.View;
import org.jgroups.blocks.RequestOptions;
import org.jgroups.blocks.ResponseMode;
import org.jgroups.blocks.RpcDispatcher;

public class Control {

    private JChannel controlChannel;

    private RpcDispatcher controlDispatcher;


    public Control() {
    }


    public void joinControl() throws Exception {
        controlChannel = new JChannel();
        controlDispatcher = new RpcDispatcher(controlChannel, new Object());
        controlChannel.setDiscardOwnMessages(true);
        controlChannel.setName("Control");
        controlChannel.connect("ControlCluster");
    }


    /**
     * Close the channels.
     */
    public void close() {
        controlChannel.close();
        controlDispatcher.stop();
    }


    public void sendCommand(String command, String target) throws Exception {

        Collection<Address> destinations = createDestinationsByTarget(target);
        Object[] args = null;
        Class<?>[] types = null;
        RequestOptions options = new RequestOptions();
        options.setMode(ResponseMode.GET_NONE);
        controlDispatcher.callRemoteMethods(destinations, command, args, types, options);
    }


    /**
     * Determine all destinations. Do not include those that are just called "Control".
     *
     * @param target If non-<code>null</code>, only query this one.
     * @return
     */
    protected Collection<Address> createDestinationsByTarget(String target) {
        Collection<Address> destinations = new ArrayList<Address>();
        if (controlChannel != null) {
            View view = controlChannel.getView();
            List<Address> members = view.getMembers();
            for (Address address : members) {
                String name = address.toString();
                if ("Control".equals(name)) {
                    // Do not send to nodes named "Control".
                    // They are not able to reply.
                } else if (target != null) {
                    if (address.toString().equals(target)) {
                        destinations.add(address);
                        System.out.println("Limited target: " + address);
                    }
                } else {
                    destinations.add(address);
                    System.out.println("Unlimited target: " + address);
                }
            }
        }
        if (destinations.isEmpty()) {
            throw new IllegalArgumentException("Unknown address \"" + target + "\"");
        }
        return destinations;
    }


    public static void main(String[] args) throws Exception {
        Control control = new Control();
        try {
            control.joinControl();
            control.sendCommand("stop", args[0]);
        } finally {
            control.close();
        }
    }
}