/*
* Copyright 2012 Future Systems
*
* 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.araqne.logdb.sort;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import org.araqne.codec.EncodingRule;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
class RunInputRandomAccess {
private final Logger logger = LoggerFactory.getLogger(RunInputRandomAccess.class);
public Run run;
private RandomAccessFile indexRaf;
private RandomAccessFile dataRaf;
private byte[] reuseBuffer = new byte[64 * 1024];
public RunInputRandomAccess(Run run) throws IOException {
this.run = run;
if (run.cached == null) {
// index file must exists here
this.indexRaf = new RandomAccessFile(run.indexFile, "r");
this.dataRaf = new RandomAccessFile(run.dataFile, "r");
}
}
public Item get(long offset) throws IOException {
if (offset >= run.length)
throw new IndexOutOfBoundsException("offset=" + offset + ", run length=" + run.length);
// anyway, you cannot cache more than int max
if (run.cached != null)
return run.cached.get((int) offset);
indexRaf.seek(8 * offset);
long pos = indexRaf.readLong();
dataRaf.seek(pos);
int len = dataRaf.readInt();
byte[] b = IoHelper.ensureBuffer(reuseBuffer, len);
int readBytes = dataRaf.read(b, 0, len);
if (readBytes != len)
throw new IOException("insufficient merge data block, expected=" + len + ", actual=" + readBytes);
return (Item) EncodingRule.decode(ByteBuffer.wrap(b, 0, len), SortCodec.instance);
}
public void close() {
if (indexRaf != null) {
try {
indexRaf.close();
} catch (IOException e) {
logger.error("araqne logdb: cannot close run", e);
}
}
if (dataRaf != null) {
try {
dataRaf.close();
} catch (IOException e) {
logger.error("araqne logdb: cannot close run", e);
}
}
}
}