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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* 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).
*
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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 ();
}