/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search licenses this
* file to you 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.apache.lucene.store.bytebuffer;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.SingleInstanceLockFactory;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* A memory based directory that uses {@link java.nio.ByteBuffer} in order to store the directory content.
*
* <p>The benefit of using {@link java.nio.ByteBuffer} is the fact that it can be stored in "native" memory
* outside of the JVM heap, thus not incurring the GC overhead of large in memory index.
*
* <p>Each "file" is segmented into one or more byte buffers.
*
* <p>If constructed with {@link ByteBufferAllocator}, it allows to control the allocation and release of
* byte buffer. For example, custom implementations can include caching of byte buffers.
*
* @author kimchy (shay.banon)
*/
public class ByteBufferDirectory extends Directory {
protected final Map<String, ByteBufferFile> files = new ConcurrentHashMap<String, ByteBufferFile>();
private final ByteBufferAllocator allocator;
private final boolean internalAllocator;
/**
* Constructs a new directory using {@link PlainByteBufferAllocator}.
*/
public ByteBufferDirectory() {
this.allocator = new PlainByteBufferAllocator(false, 1024, 1024 * 10);
this.internalAllocator = true;
try {
setLockFactory(new SingleInstanceLockFactory());
} catch (IOException e) {
// will not happen
}
}
/**
* Constructs a new byte buffer directory with a custom allocator.
*/
public ByteBufferDirectory(ByteBufferAllocator allocator) {
this.allocator = allocator;
this.internalAllocator = false;
try {
setLockFactory(new SingleInstanceLockFactory());
} catch (IOException e) {
// will not happen
}
}
public void sync(Collection<String> names) throws IOException {
// nothing to do here
}
@Override
public String[] listAll() throws IOException {
return files.keySet().toArray(new String[0]);
}
@Override
public boolean fileExists(String name) throws IOException {
return files.containsKey(name);
}
@Override
public long fileModified(String name) throws IOException {
ByteBufferFile file = files.get(name);
if (file == null)
throw new FileNotFoundException(name);
return file.getLastModified();
}
@Override
public void touchFile(String name) throws IOException {
ByteBufferFile file = files.get(name);
if (file == null)
throw new FileNotFoundException(name);
long ts2, ts1 = System.currentTimeMillis();
do {
try {
Thread.sleep(0, 1);
} catch (InterruptedException ie) {
// In 3.0 we will change this to throw
// InterruptedException instead
Thread.currentThread().interrupt();
throw new RuntimeException(ie);
}
ts2 = System.currentTimeMillis();
} while (ts1 == ts2);
file.setLastModified(ts2);
}
@Override
public void deleteFile(String name) throws IOException {
ByteBufferFile file = files.remove(name);
if (file == null)
throw new FileNotFoundException(name);
file.clean();
}
@Override
public long fileLength(String name) throws IOException {
ByteBufferFile file = files.get(name);
if (file == null)
throw new FileNotFoundException(name);
return file.getLength();
}
@Override
public IndexOutput createOutput(String name) throws IOException {
ByteBufferAllocator.Type allocatorType = ByteBufferAllocator.Type.LARGE;
if (name.contains("segments") || name.endsWith(".del")) {
allocatorType = ByteBufferAllocator.Type.SMALL;
}
ByteBufferFile file = new ByteBufferFile(this, allocator.sizeInBytes(allocatorType));
ByteBufferFile existing = files.put(name, file);
if (existing != null) {
existing.clean();
}
return new ByteBufferIndexOutput(allocator, allocatorType, file);
}
@Override
public IndexInput openInput(String name) throws IOException {
ByteBufferFile file = files.get(name);
if (file == null)
throw new FileNotFoundException(name);
return new ByteBufferIndexInput(file);
}
@Override
public void close() throws IOException {
String[] files = listAll();
for (String file : files) {
deleteFile(file);
}
if (internalAllocator) {
allocator.close();
}
}
void releaseBuffer(ByteBuffer byteBuffer) {
allocator.release(byteBuffer);
}
}