/**
*
* 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 com.alibaba.wasp.zookeeper;
import com.alibaba.wasp.DeserializationException;
import com.alibaba.wasp.protobuf.generated.LoadBalancerProtos;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.zookeeper.KeeperException;
public class LoadBalancerTracker extends ZooKeeperNodeTracker {
private static final Log LOG = LogFactory.getLog(LoadBalancerTracker.class);
public LoadBalancerTracker(ZooKeeperWatcher watcher, Abortable abortable) {
super(watcher, watcher.balancerZNode, abortable);
}
/**
* Return true if the balance switch is on, false otherwise
*/
public boolean isBalancerOn() {
byte[] upData = super.getData(false);
try {
// if data in ZK is null, use default of on.
return upData == null || parseFrom(upData).getBalancerOn();
} catch (DeserializationException dex) {
LOG.error("ZK state for LoadBalancer could not be parsed "
+ Bytes.toStringBinary(upData));
// return false to be safe.
return false;
}
}
/**
* Set the balancer on/off
*
* @param balancerOn
* @throws org.apache.zookeeper.KeeperException
*/
public void setBalancerOn(boolean balancerOn) throws KeeperException {
byte[] upData = toByteArray(balancerOn);
try {
ZKUtil.createAndWatch(watcher, watcher.balancerZNode, upData);
} catch (KeeperException.NodeExistsException nee) {
ZKUtil.setData(watcher, watcher.balancerZNode, upData);
}
super.nodeDataChanged(watcher.balancerZNode);
}
private byte[] toByteArray(boolean isBalancerOn) {
LoadBalancerProtos.LoadBalancerState.Builder builder = LoadBalancerProtos.LoadBalancerState
.newBuilder();
builder.setBalancerOn(isBalancerOn);
return builder.build().toByteArray();
}
private LoadBalancerProtos.LoadBalancerState parseFrom(byte[] pbBytes)
throws DeserializationException {
LoadBalancerProtos.LoadBalancerState.Builder builder = LoadBalancerProtos.LoadBalancerState
.newBuilder();
try {
builder.mergeFrom(pbBytes, 0, pbBytes.length);
} catch (InvalidProtocolBufferException e) {
throw new DeserializationException(e);
}
return builder.build();
}
}