java/jakarta/servlet/Registration.java

/*
 * 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 jakarta.servlet;

import java.util.Map;
import java.util.Set;

/**
 * Common interface for the registration of Filters and Servlets.
 *
 * @since Servlet 3.0
 */
public interface Registration {

    /**
     * Obtain the name of the Servlet.
     *
     * @return the name of the Servlet.
     */
    String getName();

    /**
     * Obtain the name of the implementation class for the Servlet.
     *
     * @return the name of the implementation class for the Servlet.
     */
    String getClassName();

    /**
     * Add an initialisation parameter if not already added.
     *
     * @param name  Name of initialisation parameter
     * @param value Value of initialisation parameter
     *
     * @return <code>true</code> if the initialisation parameter was set, <code>false</code> if the initialisation
     *             parameter was not set because an initialisation parameter of the same name already existed
     *
     * @throws IllegalArgumentException if name or value is <code>null</code>
     * @throws IllegalStateException    if the ServletContext associated with this registration has already been
     *                                      initialised
     */
    boolean setInitParameter(String name, String value);

    /**
     * Get the value of an initialisation parameter.
     *
     * @param name The initialisation parameter whose value is required
     *
     * @return The value of the named initialisation parameter
     */
    String getInitParameter(String name);

    /**
     * Add multiple initialisation parameters. If any of the supplied initialisation parameter conflicts with an
     * existing initialisation parameter, no updates will be performed.
     *
     * @param initParameters The initialisation parameters to add
     *
     * @return The set of initialisation parameter names that conflicted with existing initialisation parameter. If
     *             there are no conflicts, this Set will be empty.
     *
     * @throws IllegalArgumentException if any of the supplied initialisation parameters have a null name or value
     * @throws IllegalStateException    if the ServletContext associated with this registration has already been
     *                                      initialised
     */
    Set<String> setInitParameters(Map<String,String> initParameters);

    /**
     * Get the names and values of all the initialisation parameters.
     *
     * @return A Map of initialisation parameter names and associated values keyed by name
     */
    Map<String,String> getInitParameters();

    /**
     * Interface through which a Servlet or Filter registered via one of the addServlet or addFilter methods,
     * respectively, on ServletContext may be further configured.
     */
    interface Dynamic extends Registration {

        /**
         * Mark this Servlet/Filter as supported asynchronous processing.
         *
         * @param isAsyncSupported Should this Servlet/Filter support asynchronous processing
         *
         * @throws IllegalStateException if the ServletContext associated with this registration has already been
         *                                   initialised
         */
        void setAsyncSupported(boolean isAsyncSupported);
    }
}