/**
* Copyright (C) 2012-2014 the original author or authors.
*
* 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 ninja.servlet;
import javax.servlet.ServletContextEvent;
import ninja.utils.NinjaModeHelper;
import ninja.utils.NinjaPropertiesImpl;
import com.google.inject.Injector;
import com.google.inject.servlet.GuiceServletContextListener;
/**
* define in web.xml:
*
* <listener>
* <listener-class>ninja.NinjaServletListener</listener-class>
* </listener>
*
* @author zoza
*
*/
public class NinjaServletListener extends GuiceServletContextListener {
private volatile NinjaBootstrap ninjaBootstrap;
NinjaPropertiesImpl ninjaProperties = null;
String contextPath;
public synchronized void setNinjaProperties(NinjaPropertiesImpl ninjaPropertiesImpl) {
if (this.ninjaProperties != null) {
throw new IllegalStateException("NinjaProperties already set.");
} else {
this.ninjaProperties = ninjaPropertiesImpl;
}
}
@Override
public void contextInitialized(ServletContextEvent servletContextEvent) {
contextPath = servletContextEvent.getServletContext().getContextPath();
super.contextInitialized(servletContextEvent);
}
@Override
public void contextDestroyed(ServletContextEvent servletContextEvent) {
ninjaBootstrap.shutdown();
super.contextDestroyed(servletContextEvent);
}
/**
* Getting the injector is done via double locking in conjuction
* with volatile keyword for thread safety.
* See also: http://en.wikipedia.org/wiki/Double-checked_locking
*
* @return The injector for this application.
*/
@Override
public Injector getInjector() {
// fetch instance variable into method, so that we access the volatile
// global variable only once - that's better performance wise.
NinjaBootstrap ninjaBootstrapLocal = ninjaBootstrap;
if (ninjaBootstrapLocal == null) {
synchronized(this) {
ninjaBootstrapLocal = ninjaBootstrap;
if (ninjaBootstrapLocal == null) {
// if properties
if (ninjaProperties == null) {
ninjaProperties
= new NinjaPropertiesImpl(
NinjaModeHelper.determineModeFromSystemPropertiesOrProdIfNotSet());
}
ninjaBootstrap
= createNinjaBootstrap(ninjaProperties, contextPath);
ninjaBootstrapLocal = ninjaBootstrap;
}
}
}
return ninjaBootstrapLocal.getInjector();
}
private NinjaBootstrap createNinjaBootstrap(
NinjaPropertiesImpl ninjaProperties,
String contextPath) {
// we set the contextpath.
ninjaProperties.setContextPath(contextPath);
ninjaBootstrap = new NinjaBootstrap(ninjaProperties);
ninjaBootstrap.boot();
return ninjaBootstrap;
}
}