com.netflix.iep.guice.GuiceHelper Maven / Gradle / Ivy
/*
* Copyright 2015 Netflix, 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 com.netflix.iep.guice;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Module;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.ServiceLoader;
/** Helper for using guice with some basic lifecycle. */
public final class GuiceHelper {
private static final Logger LOGGER = LoggerFactory.getLogger(GuiceHelper.class);
/**
* Returns a list of all guice modules in the classpath using ServiceLoader. Modules that do
* not have a corresponding provider config.properties will not get loaded.
*/
public static List getModulesUsingServiceLoader() {
ServiceLoader loader = ServiceLoader.load(Module.class);
List modules = new ArrayList<>();
for (Module m : loader) {
modules.add(m);
}
return modules;
}
private Injector injector;
public GuiceHelper() {
}
/** Return the injector used with the lifecycle. */
public Injector getInjector() {
return injector;
}
/** Start up using the list of modules from {@link #getModulesUsingServiceLoader()}. */
public void start() throws Exception {
start(getModulesUsingServiceLoader());
}
/** Start up with an arbitrary list of modules. */
public void start(Module... modules) throws Exception {
start(Arrays.asList(modules));
}
/** Start up with an arbitrary list of modules. */
public void start(Iterable modules) throws Exception {
List ms = new ArrayList<>();
ms.add(new LifecycleModule());
for (Module m : modules) {
LOGGER.debug("adding module: {}", m.getClass());
ms.add(m);
}
injector = Guice.createInjector(ms);
}
/** Shutdown classes with {@link javax.annotation.PreDestroy}. */
public void shutdown() throws Exception {
PreDestroyList list = injector.getInstance(PreDestroyList.class);
list.invokeAll();
}
/** Add a shutdown hook for this instance. */
public void addShutdownHook() {
final Runnable r = new Runnable() {
@Override public void run() {
try {
shutdown();
} catch (Exception e) {
LOGGER.warn("exception during shutdown sequence", e);
}
}
};
Runtime.getRuntime().addShutdownHook(new Thread(r, "ShutdownHook"));
}
}