| /** |
| * 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.hadoop.hdfs.server.namenode; |
| |
| import java.io.DataInputStream; |
| import java.io.ByteArrayInputStream; |
| import java.io.IOException; |
| |
| /** |
| * An implementation of the abstract class {@link EditLogInputStream}, |
| * which is used to updates HDFS meta-data state on a backup node. |
| * |
| * @see org.apache.hadoop.hdfs.server.protocol.NamenodeProtocol#journal |
| * (org.apache.hadoop.hdfs.server.protocol.NamenodeRegistration, |
| * int, int, byte[]) |
| */ |
| class EditLogBackupInputStream extends EditLogInputStream { |
| String address; // sender address |
| private ByteBufferInputStream inner; |
| private DataInputStream in; |
| |
| /** |
| * A ByteArrayInputStream, which lets modify the underlying byte array. |
| */ |
| private static class ByteBufferInputStream extends ByteArrayInputStream { |
| ByteBufferInputStream() { |
| super(new byte[0]); |
| } |
| |
| byte[] getData() { |
| return super.buf; |
| } |
| |
| void setData(byte[] newBytes) { |
| super.buf = newBytes; |
| super.count = newBytes == null ? 0 : newBytes.length; |
| super.mark = 0; |
| reset(); |
| } |
| |
| /** |
| * Number of bytes read from the stream so far. |
| */ |
| int length() { |
| return count; |
| } |
| } |
| |
| EditLogBackupInputStream(String name) throws IOException { |
| address = name; |
| inner = new ByteBufferInputStream(); |
| in = new DataInputStream(inner); |
| } |
| |
| @Override // JournalStream |
| public String getName() { |
| return address; |
| } |
| |
| @Override // JournalStream |
| public JournalType getType() { |
| return JournalType.BACKUP; |
| } |
| |
| @Override |
| public int available() throws IOException { |
| return in.available(); |
| } |
| |
| @Override |
| public int read() throws IOException { |
| return in.read(); |
| } |
| |
| @Override |
| public int read(byte[] b, int off, int len) throws IOException { |
| return in.read(b, off, len); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| in.close(); |
| } |
| |
| @Override |
| long length() throws IOException { |
| // file size + size of both buffers |
| return inner.length(); |
| } |
| |
| DataInputStream getDataInputStream() { |
| return in; |
| } |
| |
| void setBytes(byte[] newBytes) throws IOException { |
| inner.setData(newBytes); |
| in.reset(); |
| } |
| |
| void clear() throws IOException { |
| setBytes(null); |
| } |
| } |