/**
*
* 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.master;
import com.alibaba.wasp.ServerName;
import org.apache.commons.lang.NotImplementedException;
import java.util.Collection;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
/**
* Class to hold dead servers list and utility querying dead server list.
*/
public class DeadServer implements Set<ServerName>, Cloneable {
/**
* Set of known dead servers. On znode expiration, servers are added here.
* This is needed in case of a network partitioning where the server's lease
* expires, but the server is still running. After the network is healed,
* and it's server logs are recovered, it will be told to call server startup
* because by then, its entityGroups have probably been reassigned.
*/
private final Set<ServerName> deadServers = new HashSet<ServerName>();
/** Number of dead servers currently being processed */
private int numProcessing;
public DeadServer() {
super();
this.numProcessing = 0;
}
/**
* @param serverName Server name
* @return true if server is dead
*/
public boolean isDeadServer(final String serverName) {
return isDeadServer(new ServerName(serverName));
}
/**
* A dead server that comes back alive has a different start code.
* @param newServerName Servername as either <code>host:port</code> or
* <code>host,port,startcode</code>.
* @return true if this server was dead before and coming back alive again
*/
public boolean cleanPreviousInstance(final ServerName newServerName) {
ServerName sn =
ServerName.findServerWithSameHostnamePort(this.deadServers, newServerName);
if (sn == null) return false;
return this.deadServers.remove(sn);
}
/**
* @param serverName
* @return true if this server is on the dead servers list.
*/
boolean isDeadServer(final ServerName serverName) {
return this.deadServers.contains(serverName);
}
/**
* @return True if we have a server with matching hostname and port.
*/
boolean isDeadServerWithSameHostnamePort(final ServerName serverName) {
return ServerName.findServerWithSameHostnamePort(this.deadServers,
serverName) != null;
}
/**
* Checks if there are currently any dead servers being processed by the
* master. Returns true if at least one entityGroup server is currently being
* processed as dead.
* @return true if any RS are being processed as dead
*/
public boolean areDeadServersInProgress() {
return numProcessing != 0;
}
public synchronized Set<ServerName> clone() {
Set<ServerName> clone = new HashSet<ServerName>(this.deadServers.size());
clone.addAll(this.deadServers);
return clone;
}
public synchronized boolean add(ServerName e) {
this.numProcessing++;
return deadServers.add(e);
}
public synchronized void finish(ServerName e) {
this.numProcessing--;
}
public synchronized int size() {
return deadServers.size();
}
public synchronized boolean isEmpty() {
return deadServers.isEmpty();
}
public synchronized boolean contains(Object o) {
return deadServers.contains(o);
}
public Iterator<ServerName> iterator() {
return this.deadServers.iterator();
}
public synchronized Object[] toArray() {
return deadServers.toArray();
}
public synchronized <T> T[] toArray(T[] a) {
return deadServers.toArray(a);
}
public synchronized boolean remove(Object o) {
return this.deadServers.remove(o);
}
public synchronized boolean containsAll(Collection<?> c) {
return deadServers.containsAll(c);
}
public synchronized boolean addAll(Collection<? extends ServerName> c) {
return deadServers.addAll(c);
}
public synchronized boolean retainAll(Collection<?> c) {
return deadServers.retainAll(c);
}
public synchronized boolean removeAll(Collection<?> c) {
return deadServers.removeAll(c);
}
public synchronized void clear() {
throw new NotImplementedException();
}
public synchronized boolean equals(Object o) {
return deadServers.equals(o);
}
public synchronized int hashCode() {
return deadServers.hashCode();
}
public synchronized String toString() {
return this.deadServers.toString();
}
}