001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027
028package org.apache.http.nio.entity;
029
030import java.io.Closeable;
031import java.io.IOException;
032
033import org.apache.http.nio.ContentEncoder;
034import org.apache.http.nio.IOControl;
035
036/**
037 * {@code HttpAsyncContentProducer} is a callback interface whose methods
038 * get invoked to stream out message content to a non-blocking HTTP connection.
039 *
040 * @since 4.2
041 */
042public interface HttpAsyncContentProducer extends Closeable {
043
044    /**
045     * Invoked to write out a chunk of content to the {@link ContentEncoder}.
046     * The {@link IOControl} interface can be used to suspend output event
047     * notifications if the entity is temporarily unable to produce more content.
048     * <p>
049     * When all content is finished, the producer <b>MUST</b> call
050     * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
051     * to be incorrectly delimited.
052     * <p>
053     * Please note that the {@link ContentEncoder} object is not thread-safe and
054     * should only be used within the context of this method call.
055     * The {@link IOControl} object can be shared and used on other thread
056     * to resume output event notifications when more content is made available.
057     *
058     * @param encoder content encoder.
059     * @param ioctrl I/O control of the underlying connection.
060     */
061    void produceContent(ContentEncoder encoder, IOControl ioctrl) throws IOException;
062
063    /**
064     * Determines whether or not this producer is capable of producing
065     * its content more than once. Repeatable content producers are expected
066     * to be able to recreate their content even after having been closed.
067     */
068    boolean isRepeatable();
069
070}