com.pivotal.gemfirexd.FabricServiceManager Maven / Gradle / Ivy
/*
* Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
*
* Licensed 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. See accompanying
* LICENSE file.
*/
package com.pivotal.gemfirexd;
import com.pivotal.gemfirexd.internal.engine.fabricservice.FabricAgentImpl;
import com.pivotal.gemfirexd.internal.engine.fabricservice.FabricLocatorImpl;
import com.pivotal.gemfirexd.internal.engine.fabricservice.FabricServerImpl;
import com.pivotal.gemfirexd.internal.engine.fabricservice.FabricServiceImpl;
/**
* A factory class for returning singleton instance of either a
* {@link FabricServer} or {@link FabricLocator}. A
* node can be booted as either a {@link FabricServer} or a
* {@link FabricLocator} but not both. To start a fabric server with an embedded
* locator use the "start-locator" property. See
* {@link FabricServer} and {@link FabricLocator} for
* more information on managing servers and locators.
*
* @author Soubhik C
*/
public abstract class FabricServiceManager {
private static final Object instanceLock = new Object();
private FabricServiceManager() {
}
/**
* Get the singleton instance of {@link FabricServer}.
*/
public final static FabricServer getFabricServerInstance() {
FabricService instance = FabricServiceImpl.getInstance();
if (instance != null) {
return checkServerInstance(instance);
}
synchronized (instanceLock) {
if ((instance = FabricServiceImpl.getInstance()) == null) {
final FabricServer server = new FabricServerImpl();
FabricServiceImpl.setInstance(server);
return server;
}
return checkServerInstance(instance);
}
}
/**
* Get the singleton instance of {@link FabricLocator}.
*/
public final static FabricLocator getFabricLocatorInstance() {
FabricService instance = FabricServiceImpl.getInstance();
if (instance != null) {
return checkLocatorInstance(instance);
}
synchronized (instanceLock) {
if ((instance = FabricServiceImpl.getInstance()) == null) {
final FabricLocator locator = new FabricLocatorImpl();
FabricServiceImpl.setInstance(locator);
return locator;
}
return checkLocatorInstance(instance);
}
}
/**
* Get the singleton instance of {@link FabricAgent}.
*/
public final static FabricAgent getFabricAgentInstance() {
FabricService instance = FabricServiceImpl.getInstance();
if (instance != null) {
return checkAgentInstance(instance);
}
synchronized (instanceLock) {
if ((instance = FabricServiceImpl.getInstance()) == null) {
final FabricAgent agent = new FabricAgentImpl();
FabricServiceImpl.setInstance(agent);
return agent;
}
return checkAgentInstance(instance);
}
}
/**
* Get the current instance of either {@link FabricServer} or
* {@link FabricLocator}. This can be null if neither of
* {@link #getFabricServerInstance()} or {@link #getFabricLocatorInstance()}
* have been invoked, or the instance has been stopped.
*/
public final static FabricService currentFabricServiceInstance() {
return FabricServiceImpl.getInstance();
}
private static FabricServer checkServerInstance(final FabricService instance) {
if (instance instanceof FabricServer) {
return (FabricServer)instance;
}
throw new IllegalStateException(
"Found an existing instance of running locator (" + instance
+ "). Use getFabricLocatorInstance() to retrieve it.");
}
private static FabricLocator checkLocatorInstance(final FabricService instance) {
if (instance instanceof FabricLocator) {
return (FabricLocator)instance;
}
throw new IllegalStateException(
"Found an existing instance of running server (" + instance
+ "). Use getFabricServerInstance() to retrieve it.");
}
private static FabricAgent checkAgentInstance(final FabricService instance) {
if (instance instanceof FabricAgent) {
return (FabricAgent)instance;
}
throw new IllegalStateException(
"Found an existing instance of running locator or server (" + instance
+ "). Use getFabricServerInstance() to retrieve it.");
}
}