forked from voldemort/voldemort
/
ByteBufferBackedInputStream.java
96 lines (79 loc) · 2.73 KB
/
ByteBufferBackedInputStream.java
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/*
* Copyright 2009 Mustard Grain, Inc
*
* Licensed 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 voldemort.common.nio;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import org.apache.commons.lang.mutable.MutableLong;
import voldemort.annotations.concurrency.NotThreadsafe;
/**
* ByteBufferBackedInputStream allows a ByteBuffer to be the source of data for
* InputStream-based callers.
* <p/>
* This class is used to interface with callers using "classic" java.io.* APIs.
* For code that manages the ByteBufferBackedInputStream, there are accessor
* methods for the underlying buffer should it need to expand and contract on
* reuse.
*
*/
@NotThreadsafe
public class ByteBufferBackedInputStream extends InputStream {
private ByteBuffer buffer;
/**
* Reference to a size tracking object, that tracks the size of the buffer
* in bytes
*/
private MutableLong sizeTracker;
public ByteBufferBackedInputStream(ByteBuffer buffer) {
this.buffer = buffer;
this.sizeTracker = null;
}
public ByteBufferBackedInputStream(ByteBuffer buffer, MutableLong sizeTracker) {
this.buffer = buffer;
this.sizeTracker = sizeTracker;
this.sizeTracker.add(buffer.capacity());
}
public ByteBuffer getBuffer() {
return buffer;
}
public void setBuffer(ByteBuffer newBuffer) {
// update the size tracker with the new buffer size
if((sizeTracker != null && this.buffer != null && newBuffer != null)) {
sizeTracker.add(newBuffer.capacity());
sizeTracker.subtract(this.buffer.capacity());
}
this.buffer = newBuffer;
}
@Override
public int read() throws IOException {
if(!buffer.hasRemaining())
return -1;
return buffer.get() & 0xff;
}
@Override
public int read(byte[] bytes, int off, int len) throws IOException {
if(!buffer.hasRemaining())
return -1;
len = Math.min(len, buffer.remaining());
buffer.get(bytes, off, len);
return len;
}
public void close() {
if(sizeTracker != null && this.buffer != null) {
sizeTracker.subtract(this.buffer.capacity());
}
}
}