http://hc.apache.org/httpcomponents-core-ga: Apache HttpComponents Core (non-blocking I/O) (The Apache Software Foundation)
  • Julius Davies
  • Andrea Selva
  • Steffen Pingel
  • Quintin Beukes
  • Marc Beyerle
  • James Abley
  • Michajlo Matijkiw 
/*
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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
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 * <http://www.apache.org/>.
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package org.apache.http.nio.protocol;

import java.io.Closeable;
import java.io.IOException;

import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.IOControl;
import org.apache.http.protocol.HttpContext;


HttpAsyncRequestProducer is a callback interface whose methods get invoked to generate an HTTP request message and to stream message content to a non-blocking HTTP connection. 
 Repeatable request producers capable of generating the same request message more than once can be reset to their initial state by calling the resetRequest() method, at which point request producers are expected to release currently allocated resources that are no longer needed or re-acquire resources needed to repeat the process. 
Since:4.2
/**
 * {@code HttpAsyncRequestProducer} is a callback interface whose methods
 * get invoked to generate an HTTP request message and to stream message
 * content to a non-blocking HTTP connection.
 * <p>
 * Repeatable request producers capable of generating the same request
 * message more than once can be reset to their initial state by calling
 * the {@link #resetRequest()} method, at which point request producers are
 * expected to release currently allocated resources that are no longer needed
 * or re-acquire resources needed to repeat the process.
 *
 * @since 4.2
 */
public interface HttpAsyncRequestProducer extends Closeable {

    
Invoked to obtain the request target host.

/**
     * Invoked to obtain the request target host.
     */
    HttpHost getTarget();

    
Invoked to generate a HTTP request message head. The message is expected to implement the HttpEntityEnclosingRequest interface if it is to enclose a content entity. The produceContent(ContentEncoder, IOControl) method will not be invoked if HttpEntityEnclosingRequest.getEntity() returns null. 
Throws:
Returns:HTTP request message.
/**
     * Invoked to generate a HTTP request message head. The message is expected
     * to implement the {@link org.apache.http.HttpEntityEnclosingRequest} interface
     * if it is to enclose a content entity. The {@link #produceContent(
     * ContentEncoder, IOControl)} method will not be invoked if
     * {@link org.apache.http.HttpEntityEnclosingRequest#getEntity()}
     * returns {@code null}.
     *
     * @return HTTP request message.
     * @throws HttpException in case of HTTP protocol violation
     * @throws IOException in case of an I/O error
     */
    HttpRequest generateRequest() throws IOException, HttpException;

    
Invoked to write out a chunk of content to the ContentEncoder. The IOControl interface can be used to suspend output event notifications if the producer is temporarily unable to produce more content. 

When all content is finished, the producer MUST call ContentEncoder.complete(). Failure to do so may cause the entity to be incorrectly delimited. 
 Please note that the ContentEncoder object is 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:
  • encoder – content encoder.
  • ioControl – I/O control of the underlying connection.
Throws:
/**
     * Invoked to write out a chunk of content to the {@link ContentEncoder}.
     * The {@link IOControl} interface can be used to suspend output event
     * notifications if the producer is temporarily unable to produce more content.
     * <p>
     * When all content is finished, the producer <b>MUST</b> call
     * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
     * to be incorrectly delimited.
     * <p>
     * Please note that the {@link ContentEncoder} object is 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.
     *
     * @param encoder content encoder.
     * @param ioControl I/O control of the underlying connection.
     * @throws IOException in case of an I/O error
     */
    void produceContent(ContentEncoder encoder, IOControl ioControl) throws IOException;

    
Invoked to signal that the request has been fully written out.

Params:
  • context – HTTP context
/**
     * Invoked to signal that the request has been fully written out.
     *
     * @param context HTTP context
     */
    void requestCompleted(HttpContext context);

    
Invoked to signal that the response processing terminated abnormally.

Params:
  • ex – exception
/**
     * Invoked to signal that the response processing terminated abnormally.
     *
     * @param ex exception
     */
    void failed(Exception ex);

    
Determines whether or not this producer is capable of producing
HTTP request messages more than once.

/**
     * Determines whether or not this producer is capable of producing
     * HTTP request messages more than once.
     */
    boolean isRepeatable();

    
Invoked to reset the producer to its initial state. Repeatable request
producers are expected to release currently allocated resources that are
no longer needed or re-acquire resources needed to repeat the process.

Throws:
  • IOException – in case of an I/O error
/**
     * Invoked to reset the producer to its initial state. Repeatable request
     * producers are expected to release currently allocated resources that are
     * no longer needed or re-acquire resources needed to repeat the process.
     *
     * @throws IOException in case of an I/O error
     */
    void resetRequest() throws IOException;

}