mirror of
https://github.com/chrislusf/seaweedfs
synced 2024-05-26 13:20:57 +02:00
75 lines
2.3 KiB
Java
75 lines
2.3 KiB
Java
/*
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* Copyright 2014 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package seaweedfs.client.btree;
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import com.google.common.io.CountingOutputStream;
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import java.io.BufferedOutputStream;
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import java.io.DataOutputStream;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.io.RandomAccessFile;
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/**
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* Allows a stream of bytes to be written to a particular location of some backing byte stream.
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*/
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class ByteOutput {
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private final RandomAccessFile file;
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private final ResettableBufferedOutputStream bufferedOutputStream;
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private CountingOutputStream countingOutputStream;
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public ByteOutput(RandomAccessFile file) {
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this.file = file;
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bufferedOutputStream = new ResettableBufferedOutputStream(new RandomAccessFileOutputStream(file));
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}
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/**
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* Starts writing to the given offset. Can be beyond the current length of the file.
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*/
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public DataOutputStream start(long offset) throws IOException {
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file.seek(offset);
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bufferedOutputStream.clear();
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countingOutputStream = new CountingOutputStream(bufferedOutputStream);
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return new DataOutputStream(countingOutputStream);
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}
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/**
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* Returns the number of byte written since {@link #start(long)} was called.
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*/
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public long getBytesWritten() {
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return countingOutputStream.getCount();
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}
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/**
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* Finishes writing, flushing and resetting any buffered state
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*/
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public void done() throws IOException {
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countingOutputStream.flush();
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countingOutputStream = null;
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}
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private static class ResettableBufferedOutputStream extends BufferedOutputStream {
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ResettableBufferedOutputStream(OutputStream output) {
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super(output);
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}
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void clear() {
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count = 0;
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}
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}
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}
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