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;
029
030import java.io.IOException;
031import java.nio.channels.ReadableByteChannel;
032
033import org.apache.http.HttpException;
034import org.apache.http.HttpMessage;
035
036/**
037 * Abstract HTTP message parser for non-blocking connections.
038 *
039 * @since 4.0
040 */
041public interface NHttpMessageParser<T extends HttpMessage> {
042
043    /**
044     * Resets the parser. The parser will be ready to start parsing another
045     * HTTP message.
046     */
047    void reset();
048
049    /**
050     * Fills the internal buffer of the parser with input data from the
051     * given {@link ReadableByteChannel}.
052     *
053     * @param channel the input channel
054     * @return number of bytes read.
055     * @throws IOException in case of an I/O error.
056     */
057    int fillBuffer(ReadableByteChannel channel)
058        throws IOException;
059
060    /**
061     * Attempts to parse a complete message head from the content of the
062     * internal buffer. If the message in the input buffer is incomplete
063     * this method will return {@code null}.
064     *
065     * @return HTTP message head, if available, {@code null} otherwise.
066     * @throws IOException in case of an I/O error.
067     * @throws HttpException in case the HTTP message is malformed or
068     *  violates the HTTP protocol.
069     */
070    T parse() throws IOException, HttpException;
071
072}