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.entity;
029
030import org.apache.http.HttpException;
031import org.apache.http.HttpMessage;
032
033/**
034 * Represents a strategy to determine length of the enclosed content entity
035 * based on properties of the HTTP message.
036 *
037 * @since 4.0
038 */
039public interface ContentLengthStrategy {
040
041    public static final int IDENTITY         = -1;
042    public static final int CHUNKED          = -2;
043
044    /**
045     * Returns length of the given message in bytes. The returned value
046     * must be a non-negative number, {@link #IDENTITY} if the end of the
047     * message will be delimited by the end of connection, or {@link #CHUNKED}
048     * if the message is chunk coded
049     *
050     * @param message HTTP message
051     * @return content length, {@link #IDENTITY}, or {@link #CHUNKED}
052     *
053     * @throws HttpException in case of HTTP protocol violation
054     */
055    long determineLength(HttpMessage message) throws HttpException;
056
057}