ClusteringHelper.java

/*
 * ModeShape (http://www.modeshape.org)
 *
 * 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 org.modeshape.jcr;

import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.UnknownHostException;
import org.jgroups.Global;

/**
 * Utility class which should be used by tests running in JGroups clusters.
 *
 * @author Horia Chiorean (hchiorea@redhat.com)
 */
public final class ClusteringHelper {

    private ClusteringHelper() {
    }

    /**
     * Binds JGroups to 'localhost'.
     *
     * @throws UnknownHostException if 'localhost' cannot be determined on the running machine.
     */
    public static void bindJGroupsToLocalAddress() throws UnknownHostException {
        InetAddress localHost = getLocalHost();
        System.setProperty(Global.BIND_ADDR, localHost.getHostAddress());
        System.setProperty(Global.EXTERNAL_ADDR, localHost.getHostAddress());
    }

    public static InetAddress getLocalHost() throws UnknownHostException {
        boolean preferIpv6 = Boolean.getBoolean(Global.IPv6);

        InetAddress localHost = null;
        InetAddress nonInet6Address = null; 
        InetAddress[] localHostAddresses = InetAddress.getAllByName("localhost");
        
        for (InetAddress localAddress : localHostAddresses) {
            if (preferIpv6 && localAddress instanceof Inet6Address) {
                localHost = localAddress;
                break;
            }else{
                if(nonInet6Address == null){
                    nonInet6Address = localAddress;
                }
            }
        }

        if(localHost == null){
            localHost = nonInet6Address;
        }

        assert localHost != null;
        return localHost;
    }

    /**
     * Removes any custom JGroups bindings.
     */
    public static void removeJGroupsBindings() {
        System.clearProperty(Global.BIND_ADDR);
        System.clearProperty(Global.EXTERNAL_ADDR);
    }
}