org.apache.zookeeper.server.command.AbstractFourLetterCommand Maven / Gradle / Ivy
/*
* 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.zookeeper.server.command;
import java.io.IOException;
import java.io.PrintWriter;
import org.apache.zookeeper.server.ServerCnxn;
import org.apache.zookeeper.server.ServerCnxnFactory;
import org.apache.zookeeper.server.ZooKeeperServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Set of threads for command ports. All the 4 letter commands are run via a
* thread. Each class maps to a corresponding 4 letter command. CommandThread is
* the abstract class from which all the others inherit.
*/
public abstract class AbstractFourLetterCommand {
private static final Logger LOG = LoggerFactory.getLogger(AbstractFourLetterCommand.class);
public static final String ZK_NOT_SERVING = "This ZooKeeper instance is not currently serving requests";
protected PrintWriter pw;
protected ServerCnxn serverCnxn;
protected ZooKeeperServer zkServer;
protected ServerCnxnFactory factory;
public AbstractFourLetterCommand(PrintWriter pw, ServerCnxn serverCnxn) {
this.pw = pw;
this.serverCnxn = serverCnxn;
}
public void start() {
run();
}
public void run() {
try {
commandRun();
} catch (IOException ie) {
LOG.error("Error in running command ", ie);
} finally {
serverCnxn.cleanupWriterSocket(pw);
}
}
public void setZkServer(ZooKeeperServer zkServer) {
this.zkServer = zkServer;
}
/**
* @return true if the server is running, false otherwise.
*/
boolean isZKServerRunning() {
return zkServer != null && zkServer.isRunning();
}
public void setFactory(ServerCnxnFactory factory) {
this.factory = factory;
}
public abstract void commandRun() throws IOException;
}