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 * KIND, either express or implied.  See the License for the
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 * This software consists of voluntary contributions made by many
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package org.apache.http.nio;

import java.io.IOException;

import org.apache.http.HttpException;

Abstract client-side HTTP protocol handler.
Since:
4.2/**
 * Abstract client-side HTTP protocol handler.
 *
 * @since 4.2
 */
public interface NHttpClientEventHandler {

    
Triggered when a new outgoing connection is created.
Params:
conn – new outgoing HTTP connection.
attachment – an object that was attached to the session request/**
     * Triggered when a new outgoing connection is created.
     *
     * @param conn new outgoing HTTP connection.
     * @param attachment an object that was attached to the session request
     */
    void connected(
            NHttpClientConnection conn,
            Object attachment) throws IOException, HttpException;

    
Triggered when the connection is ready to accept a new HTTP request.
The protocol handler does not have to submit a request if it is not
ready.
Params:
conn – HTTP connection that is ready to accept a new HTTP request.
See Also:
NHttpClientConnection/**
     * Triggered when the connection is ready to accept a new HTTP request.
     * The protocol handler does not have to submit a request if it is not
     * ready.
     *
     * @see NHttpClientConnection
     *
     * @param conn HTTP connection that is ready to accept a new HTTP request.
     */
    void requestReady(
            NHttpClientConnection conn) throws IOException, HttpException;

    
Triggered when an HTTP response is received. The connection
passed as a parameter to this method is guaranteed to return
a valid HTTP response object.
 If the response received encloses a response entity this method will be followed by a series of inputReady(NHttpClientConnection, ContentDecoder) calls to transfer the response content. 
Params:
conn – HTTP connection that contains an HTTP response
See Also:
NHttpClientConnection/**
     * Triggered when an HTTP response is received. The connection
     * passed as a parameter to this method is guaranteed to return
     * a valid HTTP response object.
     * <p>
     * If the response received encloses a response entity this method will
     * be followed by a series of
     * {@link #inputReady(NHttpClientConnection, ContentDecoder)} calls
     * to transfer the response content.
     *
     * @see NHttpClientConnection
     *
     * @param conn HTTP connection that contains an HTTP response
     */
    void responseReceived(
            NHttpClientConnection conn) throws IOException, HttpException;

    
Triggered when the underlying channel is ready for reading a
new portion of the response entity through the corresponding
content decoder.
 If the content consumer is unable to process incoming content, input event notifications can be temporarily suspended using IOControl interface (super interface of NHttpClientConnection). 
 Please note that the NHttpClientConnection and ContentDecoder objects are not thread-safe and should only be used within the context of this method call. The IOControl object can be shared and used on other thread to resume input event notifications when the handler is capable of processing more content. 
Params:
conn – HTTP connection that can produce a new portion of the
incoming response content.
decoder – The content decoder to use to read content.
See Also:
NHttpClientConnection
ContentDecoder
IOControl/**
     * Triggered when the underlying channel is ready for reading a
     * new portion of the response entity through the corresponding
     * content decoder.
     * <p>
     * If the content consumer is unable to process incoming content,
     * input event notifications can be temporarily suspended using
     * {@link IOControl} interface (super interface of {@link NHttpClientConnection}).
     * <p>
     * Please note that the {@link NHttpClientConnection} and {@link ContentDecoder}
     * objects are not thread-safe and should only be used within the context of
     * this method call. The {@link IOControl} object can be shared and used on other
     * thread to resume input event notifications when the handler is capable of
     * processing more content.
     *
     * @see NHttpClientConnection
     * @see ContentDecoder
     * @see IOControl
     *
     * @param conn HTTP connection that can produce a new portion of the
     * incoming response content.
     * @param decoder The content decoder to use to read content.
     */
    void inputReady(
            NHttpClientConnection conn,
            ContentDecoder decoder) throws IOException, HttpException;

    
Triggered when the underlying channel is ready for writing a next portion
of the request entity through the corresponding content encoder.
 If the content producer is unable to generate outgoing content, output event notifications can be temporarily suspended using IOControl interface (super interface of NHttpClientConnection). 
 Please note that the NHttpClientConnection and ContentEncoder objects are not thread-safe and should only be used within the context of this method call. The IOControl object can be shared and used on other thread to resume output event notifications when more content is made available. 
Params:
conn – HTTP connection that can accommodate a new portion
of the outgoing request content.
encoder – The content encoder to use to write content.
See Also:
NHttpClientConnection
ContentEncoder
IOControl/**
     * Triggered when the underlying channel is ready for writing a next portion
     * of the request entity through the corresponding content encoder.
     * <p>
     * If the content producer is unable to generate outgoing content,
     * output event notifications can be temporarily suspended using
     * {@link IOControl} interface (super interface of {@link NHttpClientConnection}).
     * <p>
     * Please note that the {@link NHttpClientConnection} and {@link ContentEncoder}
     * objects are not thread-safe and should only be used within the context of
     * this method call. The {@link IOControl} object can be shared and used on other
     * thread to resume output event notifications when more content is made available.
     *
     * @see NHttpClientConnection
     * @see ContentEncoder
     * @see IOControl
     *
     * @param conn HTTP connection that can accommodate a new portion
     * of the outgoing request content.
     * @param encoder The content encoder to use to write content.
     */
    void outputReady(
            NHttpClientConnection conn,
            ContentEncoder encoder) throws IOException, HttpException;

    
Triggered when the connection is closed by the opposite end point
(half-closed).
Params:
conn – half-closed HTTP connection./**
     * Triggered when the connection is closed by the opposite end point
     * (half-closed).
     *
     * @param conn half-closed HTTP connection.
     */
    void endOfInput(
            NHttpClientConnection conn) throws IOException;

    
Triggered when no input is detected on this connection over the
maximum period of inactivity.
Params:
conn – HTTP connection that caused timeout condition./**
     * Triggered when no input is detected on this connection over the
     * maximum period of inactivity.
     *
     * @param conn HTTP connection that caused timeout condition.
     */
    void timeout(
            NHttpClientConnection conn) throws IOException, HttpException;

    
Triggered when the connection is closed.
Params:
conn – closed HTTP connection./**
     * Triggered when the connection is closed.
     *
     * @param conn closed HTTP connection.
     */
    void closed(NHttpClientConnection conn);

    
Triggered if an error occurs during the HTTP exchange.
Params:
conn – HTTP connection that caused an I/O error
ex – exception/**
     * Triggered if an error occurs during the HTTP exchange.
     *
     * @param conn HTTP connection that caused an I/O error
     * @param ex exception
     */
    void exception(NHttpClientConnection conn, Exception ex);

}