javax.servlet.ServletContainerInitializer Maven / Gradle / Ivy
/*
* Copyright (c) 2017, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.servlet;
import java.util.Set;
/**
* Interface which allows a library/runtime to be notified of a web
* application's startup phase and perform any required programmatic
* registration of servlets, filters, and listeners in response to it.
*
* Implementations of this interface may be annotated with
* {@link javax.servlet.annotation.HandlesTypes HandlesTypes}, in order to
* receive (at their {@link #onStartup} method) the Set of application
* classes that implement, extend, or have been annotated with the class
* types specified by the annotation.
*
*
If an implementation of this interface does not use HandlesTypes
* annotation, or none of the application classes match the ones specified
* by the annotation, the container must pass a null Set of classes
* to {@link #onStartup}.
*
*
When examining the classes of an application to see if they match
* any of the criteria specified by the HandlesTypes annotation
* of a ServletContainerInitializer, the container may run into
* classloading problems if any of the application's optional JAR
* files are missing. Because the container is not in a position to decide
* whether these types of classloading failures will prevent
* the application from working correctly, it must ignore them,
* while at the same time providing a configuration option that would
* log them.
*
*
Implementations of this interface must be declared by a JAR file
* resource located inside the META-INF/services directory and
* named for the fully qualified class name of this interface, and will be
* discovered using the runtime's service provider lookup mechanism
* or a container specific mechanism that is semantically equivalent to
* it. In either case, ServletContainerInitializer services from web
* fragment JAR files excluded from an absolute ordering must be ignored,
* and the order in which these services are discovered must follow the
* application's classloading delegation model.
*
* @see javax.servlet.annotation.HandlesTypes
*
* @since Servlet 3.0
*/
public interface ServletContainerInitializer {
/**
* Notifies this ServletContainerInitializer of the startup
* of the application represented by the given ServletContext.
*
*
If this ServletContainerInitializer is bundled in a JAR
* file inside the WEB-INF/lib directory of an application,
* its onStartup method will be invoked only once during the
* startup of the bundling application. If this
* ServletContainerInitializer is bundled inside a JAR file
* outside of any WEB-INF/lib directory, but still
* discoverable as described above, its onStartup method
* will be invoked every time an application is started.
*
* @param c the Set of application classes that extend, implement, or
* have been annotated with the class types specified by the
* {@link javax.servlet.annotation.HandlesTypes HandlesTypes} annotation,
* or null if there are no matches, or this
* ServletContainerInitializer has not been annotated with
* HandlesTypes
*
* @param ctx the ServletContext of the web application that
* is being started and in which the classes contained in c
* were found
*
* @throws ServletException if an error has occurred
*/
public void onStartup(Set> c, ServletContext ctx)
throws ServletException;
}