001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.core.file; 021 022import java.nio.channels.FileChannel; 023 024/** 025 * Indicates the region of a file to be sent to the remote host. 026 * 027 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 028 */ 029public interface FileRegion { 030 031 /** 032 * The open <tt>FileChannel</tt> from which data will be read to send to 033 * remote host. 034 * 035 * @return An open <tt>FileChannel</tt>. 036 */ 037 FileChannel getFileChannel(); 038 039 /** 040 * The current file position from which data will be read. 041 * 042 * @return The current file position. 043 */ 044 long getPosition(); 045 046 /** 047 * Updates the current file position based on the specified amount. This 048 * increases the value returned by {@link #getPosition()} and 049 * {@link #getWrittenBytes()} by the given amount and decreases the value 050 * returned by {@link #getRemainingBytes()} by the given {@code amount}. 051 * 052 * @param amount 053 * The new value for the file position. 054 */ 055 void update(long amount); 056 057 /** 058 * The number of bytes remaining to be written from the file to the remote 059 * host. 060 * 061 * @return The number of bytes remaining to be written. 062 */ 063 long getRemainingBytes(); 064 065 /** 066 * The total number of bytes already written. 067 * 068 * @return The total number of bytes already written. 069 */ 070 long getWrittenBytes(); 071 072 /** 073 * Provides an absolute filename for the underlying FileChannel. 074 * 075 * @return the absolute filename, or <tt>null</tt> if the FileRegion 076 * does not know the filename 077 */ 078 String getFilename(); 079}