| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.bookkeeper.bookie; |
| |
| import java.io.IOException; |
| import java.nio.channels.FileChannel; |
| |
| /** |
| * A {@code BufferedChannelBase} adds functionality to an existing file channel, the ability |
| * to buffer the input and output data. This class is a base class for wrapping the {@link FileChannel}. |
| */ |
| public abstract class BufferedChannelBase { |
| static class BufferedChannelClosedException extends IOException { |
| BufferedChannelClosedException() { |
| super("Attempting to access a file channel that has already been closed"); |
| } |
| } |
| |
| protected final FileChannel fileChannel; |
| |
| protected BufferedChannelBase(FileChannel fc) { |
| this.fileChannel = fc; |
| } |
| |
| protected FileChannel validateAndGetFileChannel() throws IOException { |
| // Even if we have BufferedChannelBase objects in the cache, higher layers should |
| // guarantee that once a log file has been closed and possibly deleted during garbage |
| // collection, attempts will not be made to read from it |
| if (!fileChannel.isOpen()) { |
| throw new BufferedChannelClosedException(); |
| } |
| return fileChannel; |
| } |
| |
| /** |
| * Get the current size of the underlying FileChannel. |
| * @return |
| */ |
| public long size() throws IOException { |
| return validateAndGetFileChannel().size(); |
| } |
| |
| } |