FSDataInputStream.java
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上传日期:2018-01-08
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文件大小:2k
- /**
- * 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.fs;
- import java.io.*;
- /** Utility that wraps a {@link FSInputStream} in a {@link DataInputStream}
- * and buffers input through a {@link BufferedInputStream}. */
- public class FSDataInputStream extends DataInputStream
- implements Seekable, PositionedReadable {
- public FSDataInputStream(InputStream in)
- throws IOException {
- super(in);
- if( !(in instanceof Seekable) || !(in instanceof PositionedReadable) ) {
- throw new IllegalArgumentException(
- "In is not an instance of Seekable or PositionedReadable");
- }
- }
-
- public synchronized void seek(long desired) throws IOException {
- ((Seekable)in).seek(desired);
- }
- public long getPos() throws IOException {
- return ((Seekable)in).getPos();
- }
-
- public int read(long position, byte[] buffer, int offset, int length)
- throws IOException {
- return ((PositionedReadable)in).read(position, buffer, offset, length);
- }
-
- public void readFully(long position, byte[] buffer, int offset, int length)
- throws IOException {
- ((PositionedReadable)in).readFully(position, buffer, offset, length);
- }
-
- public void readFully(long position, byte[] buffer)
- throws IOException {
- ((PositionedReadable)in).readFully(position, buffer, 0, buffer.length);
- }
-
- public boolean seekToNewSource(long targetPos) throws IOException {
- return ((Seekable)in).seekToNewSource(targetPos);
- }
- }