/* * Copyright (c) 2005, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.net.httpserver; import java.io.*;import java.nio.*;import java.nio.channels.*;import java.net.*;import javax.net.ssl.*;import java.util.*;import sun.net.www.MessageHeader; /** * This class encapsulates a HTTP request received and a * response to be generated in one exchange. It provides methods * for examining the request from the client, and for building and * sending the response. * <p> * The typical life-cycle of a HttpExchange is shown in the sequence * below. * <ol><li>{@link #getRequestMethod()} to determine the command * <li>{@link #getRequestHeaders()} to examine the request headers (if needed) * <li>{@link #getRequestBody()} returns a {@link java.io.InputStream} for reading the request body. *     After reading the request body, the stream is close. * <li>{@link #getResponseHeaders()} to set any response headers, except content-length * <li>{@link #sendResponseHeaders(int,long)} to send the response headers. Must be called before * next step. * <li>{@link #getResponseBody()} to get a {@link java.io.OutputStream} to send the response body. *      When the response body has been written, the stream must be closed to terminate the exchange. * </ol> * <b>Terminating exchanges</b> * <br> * Exchanges are terminated when both the request InputStream and response OutputStream are closed. * Closing the OutputStream, implicitly closes the InputStream (if it is not already closed). * However, it is recommended * to consume all the data from the InputStream before closing it. * The convenience method {@link #close()} does all of these tasks. * Closing an exchange without consuming all of the request body is not an error * but may make the underlying TCP connection unusable for following exchanges. * The effect of failing to terminate an exchange is undefined, but will typically * result in resources failing to be freed/reused. * @since 1.6 */ public abstract class HttpExchange {     protected HttpExchange () {    }     /**     * Returns an immutable Map containing the HTTP headers that were     * included with this request. The keys in this Map will be the header     * names, while the values will be a List of Strings containing each value     * that was included (either for a header that was listed several times,     * or one that accepts a comma-delimited list of values on a single line).     * In either of these cases, the values for the header name will be     * presented in the order that they were included in the request.     * <p>     * The keys in Map are case-insensitive.     * @return a read-only Map which can be used to access request headers     */    public abstract Headers getRequestHeaders () ;     /**     * Returns a mutable Map into which the HTTP response headers can be stored     * and which will be transmitted as part of this response. The keys in the     * Map will be the header names, while the values must be a List of Strings     * containing each value that should be included multiple times     * (in the order that they should be included).     * <p>     * The keys in Map are case-insensitive.     * @return a writable Map which can be used to set response headers.     */    public abstract Headers getResponseHeaders () ;     /**     * Get the request URI     *     * @return the request URI     */    public abstract URI getRequestURI () ;     /**     * Get the request method     * @return the request method     */    public abstract String getRequestMethod ();     /**     * Get the HttpContext for this exchange     * @return the HttpContext     */    public abstract HttpContext getHttpContext ();     /**     * Ends this exchange by doing the following in sequence:<p><ol>     * <li>close the request InputStream, if not already closed<p></li>     * <li>close the response OutputStream, if not already closed. </li>     * </ol>     */    public abstract void close () ;     /**     * returns a stream from which the request body can be read.     * Multiple calls to this method will return the same stream.     * It is recommended that applications should consume (read) all of the     * data from this stream before closing it. If a stream is closed     * before all data has been read, then the close() call will     * read and discard remaining data (up to an implementation specific     * number of bytes).     * @return the stream from which the request body can be read.     */    public abstract InputStream getRequestBody () ;     /**     * returns a stream to which the response body must be     * written. {@link #sendResponseHeaders(int,long)}) must be called prior to calling     * this method. Multiple calls to this method (for the same exchange)     * will return the same stream. In order to correctly terminate     * each exchange, the output stream must be closed, even if no     * response body is being sent.     * <p>     * Closing this stream implicitly     * closes the InputStream returned from {@link #getRequestBody()}     * (if it is not already closed).     * <P>     * If the call to sendResponseHeaders() specified a fixed response     * body length, then the exact number of bytes specified in that     * call must be written to this stream. If too many bytes are written,     * then write() will throw an IOException. If too few bytes are written     * then the stream close() will throw an IOException. In both cases,     * the exchange is aborted and the underlying TCP connection closed.     * @return the stream to which the response body is written     */    public abstract OutputStream getResponseBody () ;      /**     * Starts sending the response back to the client using the current set of response headers     * and the numeric response code as specified in this method. The response body length is also specified     * as follows. If the response length parameter is greater than zero, this specifies an exact     * number of bytes to send and the application must send that exact amount of data.     * If the response length parameter is <code>zero</code>, then chunked transfer encoding is     * used and an arbitrary amount of data may be sent. The application terminates the     * response body by closing the OutputStream. If response length has the value <code>-1</code>     * then no response body is being sent.     * <p>     * If the content-length response header has not already been set then     * this is set to the apropriate value depending on the response length parameter.     * <p>     * This method must be called prior to calling {@link #getResponseBody()}.     * @param rCode the response code to send     * @param responseLength if > 0, specifies a fixed response body length     *        and that exact number of bytes must be written     *        to the stream acquired from getResponseBody(), or else     *        if equal to 0, then chunked encoding is used,     *        and an arbitrary number of bytes may be written.     *        if <= -1, then no response body length is specified and     *        no response body may be written.     * @see HttpExchange#getResponseBody()     */    public abstract void sendResponseHeaders (int rCode, long responseLength) throws IOException ;     /**     * Returns the address of the remote entity invoking this request     * @return the InetSocketAddress of the caller     */    public abstract InetSocketAddress getRemoteAddress ();     /**     * Returns the response code, if it has already been set     * @return the response code, if available. <code>-1</code> if not available yet.     */    public abstract int getResponseCode ();     /**     * Returns the local address on which the request was received     * @return the InetSocketAddress of the local interface     */    public abstract InetSocketAddress getLocalAddress ();     /**     * Returns the protocol string from the request in the form     * <i>protocol/majorVersion.minorVersion</i>. For example,     * "HTTP/1.1"     * @return the protocol string from the request     */    public abstract String getProtocol ();     /**     * Filter modules may store arbitrary objects with HttpExchange     * instances as an out-of-band communication mechanism. Other Filters     * or the exchange handler may then access these objects.     * <p>     * Each Filter class will document the attributes which they make     * available.     * @param name the name of the attribute to retrieve     * @return the attribute object, or null if it does not exist     * @throws NullPointerException if name is <code>null</code>     */    public abstract Object getAttribute (String name) ;     /**     * Filter modules may store arbitrary objects with HttpExchange     * instances as an out-of-band communication mechanism. Other Filters     * or the exchange handler may then access these objects.     * <p>     * Each Filter class will document the attributes which they make     * available.     * @param name the name to associate with the attribute value     * @param value the object to store as the attribute value. <code>null</code>     * value is permitted.     * @throws NullPointerException if name is <code>null</code>     */    public abstract void setAttribute (String name, Object value) ;     /**     * Used by Filters to wrap either (or both) of this exchange's InputStream     * and OutputStream, with the given filtered streams so     * that subsequent calls to {@link #getRequestBody()} will     * return the given {@link java.io.InputStream}, and calls to     * {@link #getResponseBody()} will return the given     * {@link java.io.OutputStream}. The streams provided to this     * call must wrap the original streams, and may be (but are not     * required to be) sub-classes of {@link java.io.FilterInputStream}     * and {@link java.io.FilterOutputStream}.     * @param i the filtered input stream to set as this object's inputstream,     *          or <code>null</code> if no change.     * @param o the filtered output stream to set as this object's outputstream,     *          or <code>null</code> if no change.     */    public abstract void setStreams (InputStream i, OutputStream o);      /**     * If an authenticator is set on the HttpContext that owns this exchange,     * then this method will return the {@link HttpPrincipal} that represents     * the authenticated user for this HttpExchange.     * @return the HttpPrincipal, or <code>null</code> if no authenticator is set.     */    public abstract HttpPrincipal getPrincipal ();}