/*
* 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.coherence;
import java.io.IOException;
import java.util.HashMap;
import org.apache.lucene.index.LuceneFileNames;
import org.apache.lucene.store.IndexOutput;
/**
* Only use buckets to write the file to the index. Writes a header file and one
* or more buckets that hold the file content.
*
* <p>Allows only seeking to the first bucket, which is what Lucene does with typical
* bucket size.
*
* @author kimchy
*/
class CoherenceMemIndexOutput extends IndexOutput {
private CoherenceDirectory dir;
private String fileName;
private FileBucketKey firstBucketKey;
private FileBucketValue firstBucketValue;
private HashMap<Object, Object> flushBuckets;
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;
public CoherenceMemIndexOutput(CoherenceDirectory dir, String fileName) throws IOException {
this.dir = dir;
this.fileName = fileName;
open = true;
buffer = new byte[dir.getBucketSize()];
flushBuckets = new HashMap<Object, Object>();
// this file is overridden by Lucene, so delete it first
if (LuceneFileNames.isStaticFile(fileName)) {
dir.deleteFile(fileName);
}
}
public void writeByte(byte b) throws IOException {
if (bufferPosition == dir.getBucketSize()) {
if (seekOccured) {
throw new CoherenceDirectoryException(dir.getIndexName(), fileName, "Seek occured and overflowed first bucket");
}
flushBucket();
}
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 == dir.getBucketSize()) {
if (seekOccured) {
throw new CoherenceDirectoryException(dir.getIndexName(), fileName, "Seek occured and overflowed first bucket");
}
flushBucket();
}
int remainInBuffer = dir.getBucketSize() - 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;
try {
// flush any bucket we might have
flushBucket();
flushBuckets.put(firstBucketKey, firstBucketValue);
flushBuckets.put(new FileHeaderKey(dir.getIndexName(), fileName), new FileHeaderValue(System.currentTimeMillis(), length));
forceFlushBuckets();
buffer = null;
firstBucketKey = null;
firstBucketValue = null;
} finally {
dir.getOnGoingIndexOutputs().remove(fileName);
}
}
public long getFilePointer() {
return this.position;
}
public void seek(long pos) throws IOException {
if (pos >= dir.getBucketSize()) {
throw new CoherenceDirectoryException(dir.getIndexName(), fileName, "seek called outside of first bucket boundries");
}
// create the first bucket if still not created
if (firstBucketKey == null) {
firstBucketKey = new FileBucketKey(dir.getIndexName(), fileName, 0);
firstBucketValue = new FileBucketValue(new byte[bufferPosition]);
System.arraycopy(buffer, 0, firstBucketValue.getData(), 0, bufferPosition);
} else {
// flush the current buffer. We only seek into the first bucket
// so no need to keep it around
if (!seekOccured) {
flushBucket(currentBucketIndex, buffer, bufferPosition);
}
}
position = pos;
currentBucketIndex = 0;
bufferPosition = (int) pos;
buffer = firstBucketValue.getData();
seekOccured = true;
}
public long length() throws IOException {
return length;
}
private void flushBucket() throws IOException {
if (currentBucketIndex == 0) {
if (firstBucketKey == null) {
firstBucketKey = new FileBucketKey(dir.getIndexName(), fileName, 0);
firstBucketValue = new FileBucketValue(new byte[bufferPosition]);
System.arraycopy(buffer, 0, firstBucketValue.getData(), 0, bufferPosition);
} else {
// do nothing, we are writing directly into the first buffer
}
} else {
if (bufferPosition > 0) {
flushBucket(currentBucketIndex, buffer, bufferPosition);
}
}
currentBucketIndex++;
bufferPosition = 0;
}
private void flushBucket(long bucketIndex, byte[] buffer, int length) throws IOException {
FileBucketKey fileBucketKey = new FileBucketKey(dir.getIndexName(), fileName, bucketIndex);
FileBucketValue fileBucketValue = new FileBucketValue(new byte[length]);
System.arraycopy(buffer, 0, fileBucketValue.getData(), 0, length);
flushBuckets.put(fileBucketKey, fileBucketValue);
if (flushBuckets.size() >= dir.getFlushRate()) {
forceFlushBuckets();
}
}
private void forceFlushBuckets() throws IOException {
if (flushBuckets.size() == 0) {
return;
}
try {
dir.getCache().putAll(flushBuckets);
} catch (Exception e) {
throw new CoherenceDirectoryException(dir.getIndexName(), fileName, "Failed to flush buckets", e);
} finally {
flushBuckets.clear();
}
}
}