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 * to you under the Apache License, Version 2.0 (the
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 *   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.http.nio.protocol;

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.IOControl;
import org.apache.http.nio.entity.EntityAsyncContentProducer;
import org.apache.http.nio.entity.HttpAsyncContentProducer;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.Args;

Basic implementation of HttpAsyncResponseProducer. The producer can make use of the HttpAsyncContentProducer interface to efficiently stream out message content to the underlying non-blocking HTTP connection, if it is implemented by the HttpEntity inclosed in the response. 
See Also:
HttpAsyncContentProducer
Since:
4.2/**
 * Basic implementation of {@link HttpAsyncResponseProducer}. The producer
 * can make use of the {@link HttpAsyncContentProducer} interface to
 * efficiently stream out message content to the underlying non-blocking HTTP
 * connection, if it is implemented by the {@link HttpEntity} inclosed in
 * the response.
 *
 * @see HttpAsyncContentProducer
 *
 * @since 4.2
 */
public class BasicAsyncResponseProducer implements HttpAsyncResponseProducer {

    private final HttpResponse response;
    private final HttpAsyncContentProducer producer;

    
Creates a producer that can be used to transmit the given response message. The given content producer will be used to stream out message content. Please note that the response message is expected to enclose an HttpEntity whose properties are consistent with the behavior of the content producer. 
Params:
response – response message.
producer – response content producer./**
     * Creates a producer that can be used to transmit the given response
     * message. The given content producer will be used to stream out message
     * content. Please note that the response message is expected to enclose
     * an {@link HttpEntity} whose properties are consistent with the behavior
     * of the content producer.
     *
     * @param response response message.
     * @param producer response content producer.
     */
    protected BasicAsyncResponseProducer(
            final HttpResponse response,
            final HttpAsyncContentProducer producer) {
        super();
        Args.notNull(response, "HTTP response");
        Args.notNull(producer, "HTTP content producer");
        this.response = response;
        this.producer = producer;
    }

    
Creates a producer that can be used to transmit the given response message. If the response message encloses an HttpEntity it is also expected to implement HttpAsyncContentProducer. 
Params:
response – response message./**
     * Creates a producer that can be used to transmit the given response
     * message. If the response message encloses an {@link HttpEntity}
     * it is also expected to implement {@link HttpAsyncContentProducer}.
     *
     * @param response response message.
     */
    public BasicAsyncResponseProducer(final HttpResponse response) {
        super();
        Args.notNull(response, "HTTP response");
        this.response = response;
        final HttpEntity entity = response.getEntity();
        if (entity != null) {
            if (entity instanceof HttpAsyncContentProducer) {
                this.producer = (HttpAsyncContentProducer) entity;
            } else {
                this.producer = new EntityAsyncContentProducer(entity);
            }
        } else {
            this.producer = null;
        }
    }

    @Override
    public HttpResponse generateResponse() {
        return this.response;
    }

    @Override
    public void produceContent(
            final ContentEncoder encoder, final IOControl ioControl) throws IOException {
        if (this.producer != null) {
            this.producer.produceContent(encoder, ioControl);
            if (encoder.isCompleted()) {
                this.producer.close();
            }
        }
    }

    @Override
    public void responseCompleted(final HttpContext context) {
    }

    @Override
    public void failed(final Exception ex) {
    }

    @Override
    public void close() throws IOException {
        if (this.producer != null) {
            this.producer.close();
        }
    }

    @Override
    public String toString() {
        final StringBuilder buf = new StringBuilder();
        buf.append(this.response);
        if (this.producer != null) {
            buf.append(" ").append(this.producer);
        }
        return buf.toString();
    }

}