Showing the changes to java/pkg/com/sun/net/httpserver/Filter.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,119 @@ | |||
| 1 | /* | ||
| 2 | * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package com.sun.net.httpserver; | ||
| 27 | |||
| 28 | import java.io.IOException; | ||
| 29 | import java.util.*; | ||
| 30 | |||
| 31 | /** | ||
| 32 | * A filter used to pre- and post-process incoming requests. Pre-processing occurs | ||
| 33 | * before the application's exchange handler is invoked, and post-processing | ||
| 34 | * occurs after the exchange handler returns. Filters | ||
| 35 | * are organised in chains, and are associated with HttpContext instances. | ||
| 36 | * <p> | ||
| 37 | * Each Filter in the chain, invokes the next filter within its own | ||
| 38 | * doFilter() implementation. The final Filter in the chain invokes the applications | ||
| 39 | * exchange handler. | ||
| 40 | * @since 1.6 | ||
| 41 | */ | ||
| 42 | public abstract class Filter { | ||
| 43 | |||
| 44 | protected Filter () {} | ||
| 45 | |||
| 46 | /** | ||
| 47 | * a chain of filters associated with a HttpServer. | ||
| 48 | * Each filter in the chain is given one of these | ||
| 49 | * so it can invoke the next filter in the chain | ||
| 50 | */ | ||
| 51 | public static class Chain { | ||
| 52 | /* the last element in the chain must invoke the users | ||
| 53 | * handler | ||
| 54 | */ | ||
| 55 | private ListIterator<Filter> iter; | ||
| 56 | private HttpHandler handler; | ||
| 57 | |||
| 58 | public Chain (List<Filter> filters, HttpHandler handler) { | ||
| 59 | iter = filters.listIterator(); | ||
| 60 | this.handler = handler; | ||
| 61 | } | ||
| 62 | |||
| 63 | /** | ||
| 64 | * calls the next filter in the chain, or else | ||
| 65 | * the users exchange handler, if this is the | ||
| 66 | * final filter in the chain. The Filter may decide | ||
| 67 | * to terminate the chain, by not calling this method. | ||
| 68 | * In this case, the filter <b>must</b> send the | ||
| 69 | * response to the request, because the application's | ||
| 70 | * exchange handler will not be invoked. | ||
| 71 | * @param exchange the HttpExchange | ||
| 72 | * @throws IOException let exceptions pass up the stack | ||
| 73 | * @throws NullPointerException if exchange is <code>null</code> | ||
| 74 | */ | ||
| 75 | public void doFilter (HttpExchange exchange) throws IOException { | ||
| 76 | if (!iter.hasNext()) { | ||
| 77 | handler.handle (exchange); | ||
| 78 | } else { | ||
| 79 | Filter f = iter.next(); | ||
| 80 | f.doFilter (exchange, this); | ||
| 81 | } | ||
| 82 | } | ||
| 83 | } | ||
| 84 | |||
| 85 | /** | ||
| 86 | * Asks this filter to pre/post-process the given exchange. The filter | ||
| 87 | * can :- | ||
| 88 | * <ul><li>examine or modify the request headers</li> | ||
| 89 | * <li>filter the request body or the response body, by creating suitable | ||
| 90 | * filter streams and calling | ||
| 91 | * {@link HttpExchange#setStreams(InputStream,OutputStream)}</li> | ||
| 92 | * <li>set attribute Objects in the exchange, which other filters or the | ||
| 93 | * exchange handler can access.</li> | ||
| 94 | * <li>decide to either :-<ol> | ||
| 95 | * <li>invoke the next filter in the chain, by calling | ||
| 96 | * {@link Filter.Chain#doFilter(HttpExchange)}</li> | ||
| 97 | * <li>terminate the chain of invocation, by <b>not</b> calling | ||
| 98 | * {@link Filter.Chain#doFilter(HttpExchange)}</li></ol> | ||
| 99 | * <li>if option 1. above taken, then when doFilter() returns all subsequent | ||
| 100 | * filters in the Chain have been called, and the response headers can be | ||
| 101 | * examined or modified.</li> | ||
| 102 | * <li>if option 2. above taken, then this Filter must use the HttpExchange | ||
| 103 | * to send back an appropriate response</li></ul><p> | ||
| 104 | * @param exchange the <code>HttpExchange</code> to be filtered. | ||
| 105 | * @param chain the Chain which allows the next filter to be invoked. | ||
| 106 | * @throws IOException may be thrown by any filter module, and if | ||
| 107 | * caught, must be rethrown again. | ||
| 108 | * @throws NullPointerException if either exchange or chain are <code>null</code> | ||
| 109 | */ | ||
| 110 | public abstract void doFilter (HttpExchange exchange, Chain chain) | ||
| 111 | throws IOException; | ||
| 112 | |||
| 113 | /** | ||
| 114 | * returns a short description of this Filter | ||
| 115 | * @return a string describing the Filter | ||
| 116 | */ | ||
| 117 | public abstract String description (); | ||
| 118 | |||
| 119 | } | ||