/*
* Copyright © 2014 Cask Data, Inc.
*
* 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.
*/
package co.cask.tephra.runtime;
import com.google.inject.AbstractModule;
import com.google.inject.Module;
import com.google.inject.PrivateModule;
import com.google.inject.Provides;
import com.google.inject.Singleton;
import org.apache.twill.common.Cancellable;
import org.apache.twill.discovery.Discoverable;
import org.apache.twill.discovery.DiscoveryService;
import org.apache.twill.discovery.DiscoveryServiceClient;
import org.apache.twill.discovery.InMemoryDiscoveryService;
import org.apache.twill.discovery.ServiceDiscovered;
import org.apache.twill.discovery.ZKDiscoveryService;
import org.apache.twill.zookeeper.ZKClientService;
/**
* Provides access to Google Guice modules for in-memory, single-node, and distributed operation for
* {@link DiscoveryService} and {@link DiscoveryServiceClient}.
*/
public final class DiscoveryModules {
public Module getInMemoryModules() {
return new InMemoryDiscoveryModule();
}
public Module getSingleNodeModules() {
return new InMemoryDiscoveryModule();
}
public Module getDistributedModules() {
return new ZKDiscoveryModule();
}
private static final class InMemoryDiscoveryModule extends AbstractModule {
// ensuring to be singleton across JVM
private static final InMemoryDiscoveryService IN_MEMORY_DISCOVERY_SERVICE = new InMemoryDiscoveryService();
@Override
protected void configure() {
InMemoryDiscoveryService discovery = IN_MEMORY_DISCOVERY_SERVICE;
bind(DiscoveryService.class).toInstance(discovery);
bind(DiscoveryServiceClient.class).toInstance(discovery);
}
}
private static final class ZKDiscoveryModule extends PrivateModule {
@Override
protected void configure() {
expose(DiscoveryService.class);
expose(DiscoveryServiceClient.class);
}
@Provides
@Singleton
private ZKDiscoveryService providesZKDiscoveryService(ZKClientService zkClient) {
return new ZKDiscoveryService(zkClient);
}
@Provides
@Singleton
private DiscoveryService providesDiscoveryService(final ZKClientService zkClient,
final ZKDiscoveryService delegate) {
return new DiscoveryService() {
@Override
public Cancellable register(Discoverable discoverable) {
if (!zkClient.isRunning()) {
zkClient.startAndWait();
}
return delegate.register(discoverable);
}
};
}
@Provides
@Singleton
private DiscoveryServiceClient providesDiscoveryServiceClient(final ZKClientService zkClient,
final ZKDiscoveryService delegate) {
return new DiscoveryServiceClient() {
@Override
public ServiceDiscovered discover(String s) {
if (!zkClient.isRunning()) {
zkClient.startAndWait();
}
return delegate.discover(s);
}
};
}
}
}