/*
* Copyright 2004-2009 the original author or authors.
*
* 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 org.compass.needle.terracotta;
import java.io.IOException;
import java.util.ArrayList;
import org.apache.lucene.store.IndexOutput;
/**
* An index output that obtains a lock only when adding data to the file (to terracotta).
*
* @author kimchy
*/
public class TerracottaIndexOutput2 extends IndexOutput {
private final int bufferSize;
private final int flushRate;
private final String name;
private TerracottaFile file;
private byte[] firstBucketEntry;
private byte[] buffer;
private int bufferPosition;
private int currentBucketIndex;
private long length;
private long position;
private boolean open;
// seek occured, we only allow to work on the first bucket
private boolean seekOccured;
private ArrayList<byte[]> flushBuckets;
TerracottaIndexOutput2(TerracottaDirectory dir, String name) throws IOException {
this.name = name;
this.bufferSize = dir.getBufferSize();
this.flushRate = dir.getFlushRate();
file = new TerracottaFile();
dir.addFile(name, file);
file.lock();
// add a dummy buffer for the first one
file.addBuffer(0);
file.unlock();
open = true;
buffer = new byte[bufferSize];
flushBuckets = new ArrayList<byte[]>(flushRate);
}
public void writeByte(byte b) throws IOException {
if (bufferPosition == bufferSize) {
if (seekOccured) {
throw new IOException("Seek occured and overflowed first buffer for file [" + name + "]");
}
flushBucket(true);
}
buffer[bufferPosition++] = b;
if (!seekOccured) {
length++;
position++;
}
}
public void writeBytes(byte[] b, int offset, int len) throws IOException {
if (!seekOccured) {
position += len;
length += len;
}
while (len > 0) {
if (bufferPosition == bufferSize) {
if (seekOccured) {
throw new IOException("Seek occured and overflowed first bucket for file [" + name + "]");
}
flushBucket(true);
}
int remainInBuffer = bufferSize - bufferPosition;
int bytesToCopy = len < remainInBuffer ? len : remainInBuffer;
System.arraycopy(b, offset, buffer, bufferPosition, bytesToCopy);
offset += bytesToCopy;
len -= bytesToCopy;
bufferPosition += bytesToCopy;
}
}
public void flush() throws IOException {
// do nothing here
}
public void close() throws IOException {
if (!open) {
return;
}
open = false;
// flush any bucket we might have
flushBucket(false);
forceFlushBuckets(firstBucketEntry);
buffer = null;
firstBucketEntry = null;
}
public long getFilePointer() {
return this.position;
}
public void seek(long pos) throws IOException {
if (pos >= bufferSize) {
throw new IOException("seek called outside of first buffer boundries for file [" + name + "]");
}
// create the first bucket if still not created
if (firstBucketEntry == null) {
firstBucketEntry = new byte[bufferPosition];
System.arraycopy(buffer, 0, firstBucketEntry, 0, bufferPosition);
} else {
// flush the current buffer. We only seek into the first bucket
// so no need to keep it around
if (!seekOccured) {
flushBucket(buffer, bufferPosition, true);
}
}
position = pos;
currentBucketIndex = 0;
bufferPosition = (int) pos;
buffer = firstBucketEntry;
seekOccured = true;
}
public long length() throws IOException {
return length;
}
private void flushBucket(boolean forceFlush) throws IOException {
if (currentBucketIndex == 0) {
if (firstBucketEntry == null) {
firstBucketEntry = new byte[bufferPosition];
System.arraycopy(buffer, 0, firstBucketEntry, 0, bufferPosition);
} else {
// do nothing, we are writing directly into the first buffer
}
} else {
if (bufferPosition > 0) {
flushBucket(buffer, bufferPosition, forceFlush);
}
}
currentBucketIndex++;
bufferPosition = 0;
}
private void flushBucket(byte[] buffer, int length, boolean forceFlush) throws IOException {
byte[] data = new byte[length];
System.arraycopy(buffer, 0, data, 0, length);
flushBuckets.add(data);
if (flushBuckets.size() >= flushRate && forceFlush) {
forceFlushBuckets(null);
}
}
private void forceFlushBuckets(byte[] firstBuffer) throws IOException {
if (flushBuckets.size() == 0 && firstBuffer == null) {
return;
}
file.lock();
try {
if (!flushBuckets.isEmpty()) {
byte[][] newBuffers = flushBuckets.toArray(new byte[flushBuckets.size()][]);
file.addBuffers(newBuffers);
}
if (firstBuffer != null) {
// we only flush on close
file.setLength(length);
file.setLastModified(System.currentTimeMillis());
file.setFirstBuffer(firstBuffer);
}
} finally {
file.unlock();
flushBuckets.clear();
}
}
}