001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions Copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2014-2015 ForgeRock AS.
015 */
016
017package org.forgerock.http;
018
019import org.forgerock.http.protocol.Request;
020import org.forgerock.http.protocol.Response;
021import org.forgerock.services.context.Context;
022import org.forgerock.util.promise.NeverThrowsException;
023import org.forgerock.util.promise.Promise;
024
025/**
026 * Filters the request and/or response of an HTTP exchange.
027 */
028public interface Filter {
029    /**
030     * Filters the request and/or response of an exchange. To pass the request
031     * to the next filter or handler in the chain, the filter calls
032     * {@code next.handle(context, request)}.
033     * <p>
034     * This method may elect not to pass the request to the next filter or
035     * handler, and instead handle the request itself. It can achieve this by
036     * merely avoiding a call to {@code next.handle(context, request)}
037     * and creating its own response object. The filter is also at liberty to
038     * replace a response with another of its own by intercepting the response
039     * returned by the next handler.
040     *
041     * @param context
042     *            The request context.
043     * @param request
044     *            The request.
045     * @param next
046     *            The next filter or handler in the chain to handle the request.
047     * @return A {@code Promise} representing the response to be returned to the
048     *         client.
049     */
050    Promise<Response, NeverThrowsException> filter(Context context, Request request, Handler next);
051}