/*
* 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.sling.discovery.impl.common.resource;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ValueMap;
import org.apache.sling.discovery.InstanceDescription;
import org.apache.sling.discovery.impl.Config;
import org.apache.sling.discovery.impl.common.DefaultClusterViewImpl;
import org.apache.sling.discovery.impl.common.View;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A ClusterView which represents an established view and contains all members
* as stored in the repository at the according location
*
*/
public class EstablishedClusterView extends DefaultClusterViewImpl {
/**
* use static logger to avoid frequent initialization as is potentially the
* case with ClusterViewResource.
**/
private final static Logger logger = LoggerFactory
.getLogger(EstablishedClusterView.class);
/** Construct a new established cluster view **/
public EstablishedClusterView(final Config config, final View view,
final String localId) {
super(view.getViewId());
final Resource viewRes = view.getResource();
if (viewRes == null) {
throw new IllegalStateException("viewRes must not be null");
}
final ValueMap valueMap = viewRes.adaptTo(ValueMap.class);
if (valueMap == null) {
throw new IllegalStateException("valueMap must not be null");
}
String leaderId = valueMap.get("leaderId", String.class);
final Resource members = viewRes.getChild("members");
if (members == null) {
throw new IllegalStateException("members must not be null");
}
final Iterator<Resource> it1 = members
.getChildren().iterator();
final List<Resource> instanceRess = new LinkedList<Resource>();
while (it1.hasNext()) {
instanceRess.add(it1.next());
}
Collections.sort(instanceRess, new Comparator<Resource>() {
public int compare(Resource o1, Resource o2) {
if (o1 == o2) {
return 0;
}
if (o1 == null) {
return 1;
}
if (o2 == null) {
return -1;
}
return o1.getName().compareTo(o2.getName());
}
});
if (leaderId==null || leaderId.length()==0) {
// fallback to pre-SLING-3253: choose leader based on slingId alone.
final Resource leader = instanceRess.get(0);
leaderId = leader.getName();
}
InstanceDescription leaderInstance = null;
for (Iterator<Resource> it2 = instanceRess.iterator(); it2.hasNext();) {
Resource resource = it2.next();
Resource instanceResource = resource.getResourceResolver()
.getResource(
config.getClusterInstancesPath() + "/"
+ resource.getName());
String slingId = resource.getName();
EstablishedInstanceDescription instance = new EstablishedInstanceDescription(
this, instanceResource, slingId, slingId.equals(leaderId),
slingId.equals(localId));
if (instance.isLeader()) {
if (leaderInstance != null) {
logger.error("More than one instance chosen as leader! overwritten leader="
+ leaderInstance + ", new leader=" + instance);
}
leaderInstance = instance;
}
}
}
}