/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.openejb.client;
import org.apache.openejb.client.event.FailoverSelection;
import org.apache.openejb.client.event.RoundRobinFailoverSelection;
import java.net.URI;
import java.util.HashSet;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;
public class RoundRobinConnectionStrategy extends AbstractConnectionStrategy {
private static class RoundRobinIterable implements Iterable<URI> {
private final URI[] locations;
private final AtomicInteger index = new AtomicInteger(-1);
private RoundRobinIterable(final ClusterMetaData clusterMetaData) {
this.locations = clusterMetaData.getLocations();
}
private int index() {
final int i = index.incrementAndGet();
if (i < locations.length) {
return i;
}
index.compareAndSet(i, -1);
return index();
}
@Override
public Iterator<URI> iterator() {
return new RoundRobinIterator();
}
private class RoundRobinIterator implements Iterator<URI> {
private final Set<URI> seen = new HashSet<URI>();
@Override
public boolean hasNext() {
return seen.size() < locations.length;
}
@Override
public URI next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
final URI location = locations[index()];
seen.add(location);
return location;
}
@Override
public void remove() {
}
}
}
@Override
protected FailoverSelection createFailureEvent(final Set<URI> remaining, final Set<URI> failed, final URI uri) {
return new RoundRobinFailoverSelection(remaining, failed, uri);
}
@Override
protected Iterable<URI> createIterable(final ClusterMetaData cluster) {
return new RoundRobinIterable(cluster);
}
}