/*
* 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 org.apache.wicket.guice;
import javax.servlet.ServletContext;
import com.google.inject.Guice;
import com.google.inject.Injector;
import com.google.inject.Module;
import com.google.inject.Stage;
import org.apache.wicket.protocol.http.IWebApplicationFactory;
import org.apache.wicket.protocol.http.WebApplication;
import org.apache.wicket.protocol.http.WicketFilter;
import org.apache.wicket.util.string.Strings;
/**
* Implementation of IWebApplicationFactory that pulls the WebApplication object out of a Guice
* Module.
*
* Configuration example:
*
* <pre>
* <filter>
* <filter-name>MyApplication</filter-name>
* <filter-class>org.apache.wicket.protocol.http.WicketFilter</filter-class>
* <init-param>
* <param-name>applicationFactoryClassName</param-name>
* <param-value>org.apache.wicket.guice.GuiceWebApplicationFactory</param-value>
* </init-param>
* <init-param>
* <param-name>module</param-name>
* <param-value>com.company.MyGuiceModule,com.company.MyOtherGuiceModule</param-value>
* </init-param>
* <init-param>
* <param-name>wicket-guice.stage</param-name>
* <param-value>DEVELOPMENT</param-value>
* </init-param>
* </filter>
* </pre>
*
* This factory will create an Injector configured using the Guice Module implementation you pass it
* above. Multiple modules can be specified by naming multiple classes separated by a comma. The
* Guice Module (MyGuiceModule in the example above) needs to bind WebApplication.class and provide
* a concrete implementation of it.
*
* The stage used when creating the Injector may be specified by the optional wicket-guice.stage
* parameter. When this parameter is not present this factory does not use specify a Stage when
* creating the Injector. This parameter can also be set as a context parameter to provide
* configuration for all instances in the web application.
*
* Alternatively, you can dig the Injector out of the ServletContext as an attribute, like so:
*
* <pre>
* <filter>
* <filter-name>MyApplication</filter-name>
* <filter-class>org.apache.wicket.protocol.http.WicketFilter</filter-class>
* <init-param>
* <param-name>applicationFactoryClassName</param-name>
* <param-value>org.apache.wicket.guice.GuiceWebApplicationFactory</param-value>
* </init-param>
* <init-param>
* <param-name>injectorContextAttribute</param-name>
* <param-value>GuiceInjector</param-value>
* </init-param>
* </filter>
* </pre>
*
* <b>NB: You no longer have to add a GuiceComponentInjector manually in your
* {@link WebApplication#init()} method - this factory will do that for you automatically.</b>
*
* @author Alastair Maw (almaw)
*
*/
public class GuiceWebApplicationFactory implements IWebApplicationFactory
{
/** */
public static final String STAGE_PARAMETER = "wicket-guice.stage";
/**
* @see IWebApplicationFactory#createApplication(WicketFilter)
*/
public WebApplication createApplication(final WicketFilter filter)
{
Injector injector;
String injectorContextAttribute = filter.getFilterConfig().getInitParameter(
"injectorContextAttribute");
Stage stage = null;
String stageContextAttribute = filter.getFilterConfig().getInitParameter(STAGE_PARAMETER);
if (stageContextAttribute == null)
{
stageContextAttribute = filter.getFilterConfig()
.getServletContext()
.getInitParameter(STAGE_PARAMETER);
}
if (stageContextAttribute != null)
{
stage = Stage.valueOf(stageContextAttribute.trim());
}
if (injectorContextAttribute != null)
{
ServletContext sc = filter.getFilterConfig().getServletContext();
// Try to dig the Injector out of the ServletContext, for integration with context
// listener-based instantiation of Guice.
injector = (Injector)sc.getAttribute(injectorContextAttribute);
if (injector == null)
{
throw new RuntimeException(
"Could not find Guice Injector in the ServletContext under attribute: " +
injectorContextAttribute);
}
}
else if (filter.getFilterConfig().getInitParameter("module") != null)
{
String paramValue = filter.getFilterConfig().getInitParameter("module");
String moduleNames[] = Strings.split(paramValue, ',');
Module modules[] = new Module[moduleNames.length];
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
for (int i = 0; i < moduleNames.length; i++)
{
String moduleName = moduleNames[i].trim();
try
{
// see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6500212
Class<?> moduleClazz = Class.forName(moduleName, false, classLoader);
Object moduleObject = moduleClazz.newInstance();
modules[i] = (Module)moduleObject;
}
catch (InstantiationException e)
{
throw new RuntimeException(
"Could not create new instance of Guice Module class " + moduleName, e);
}
catch (ClassNotFoundException e)
{
throw new RuntimeException(
"Could not create new instance of Guice Module class " + moduleName, e);
}
catch (IllegalAccessException e)
{
throw new RuntimeException(
"Could not create new instance of Guice Module class " + moduleName, e);
}
}
if (stage != null)
{
injector = Guice.createInjector(stage, modules);
}
else
{
injector = Guice.createInjector(modules);
}
}
else
{
throw new RuntimeException(
"To use GuiceWebApplicationFactory, you must specify either an 'injectorContextAttribute' or a 'module' init-param.");
}
WebApplication app = injector.getInstance(WebApplication.class);
app.getComponentInstantiationListeners().add(new GuiceComponentInjector(app, injector));
return app;
}
/** {@inheritDoc} */
public void destroy(final WicketFilter filter)
{
}
}