org.mwg.LevelDBStorage Maven / Gradle / Ivy
/**
* Copyright 2017 The MWG Authors. All rights reserved.
*
* 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.mwg;
import org.fusesource.leveldbjni.JniDBFactory;
import org.iq80.leveldb.CompressionType;
import org.iq80.leveldb.DB;
import org.iq80.leveldb.Options;
import org.iq80.leveldb.WriteBatch;
import org.iq80.leveldb.impl.Iq80DBFactory;
import org.mwg.plugin.Storage;
import org.mwg.struct.Buffer;
import org.mwg.struct.BufferIterator;
import org.mwg.utility.Base64;
import java.io.File;
public class LevelDBStorage implements Storage {
private static final String _connectedError = "PLEASE CONNECT YOUR DATABASE FIRST";
private static final byte[] prefixKey = "prefix".getBytes();
private final String storagePath;
private DB db;
private boolean isConnected;
private Graph graph;
private boolean useNative = true;
public LevelDBStorage(String storagePath) {
this.isConnected = false;
this.storagePath = storagePath;
}
public LevelDBStorage useNative(boolean p_useNative) {
this.useNative = p_useNative;
return this;
}
@Override
public void get(Buffer keys, Callback callback) {
if (!isConnected) {
throw new RuntimeException(_connectedError);
}
Buffer result = graph.newBuffer();
BufferIterator it = keys.iterator();
boolean isFirst = true;
while (it.hasNext()) {
Buffer view = it.next();
try {
if (!isFirst) {
result.write(Constants.BUFFER_SEP);
} else {
isFirst = false;
}
byte[] res = db.get(view.data());
if (res != null) {
result.writeAll(res);
}
} catch (Exception e) {
e.printStackTrace();
}
}
if (callback != null) {
callback.on(result);
}
}
@Override
public void put(Buffer stream, Callback callback) {
if (!isConnected) {
throw new RuntimeException(_connectedError);
}
try {
WriteBatch batch = db.createWriteBatch();
BufferIterator it = stream.iterator();
while (it.hasNext()) {
Buffer keyView = it.next();
Buffer valueView = it.next();
if (valueView != null) {
batch.put(keyView.data(), valueView.data());
}
}
db.write(batch);
if (callback != null) {
callback.on(true);
}
} catch (Exception e) {
e.printStackTrace();
if (callback != null) {
callback.on(false);
}
}
}
@Override
public void remove(Buffer keys, Callback callback) {
if (!isConnected) {
throw new RuntimeException(_connectedError);
}
try {
BufferIterator it = keys.iterator();
while (it.hasNext()) {
Buffer view = it.next();
db.delete(view.data());
}
if (callback != null) {
callback.on(null);
}
} catch (Exception e) {
e.printStackTrace();
if (callback != null) {
callback.on(false);
}
}
}
@Override
public void disconnect(Callback callback) {
try {
db.close();
db = null;
isConnected = false;
if (callback != null) {
callback.on(true);
}
} catch (Exception e) {
e.printStackTrace();
if (callback != null) {
callback.on(false);
}
}
}
@Override
public void connect(Graph graph, Callback callback) {
if (isConnected) {
if (callback != null) {
callback.on(null);
}
return;
}
this.graph = graph;
//by default activate snappy compression of bytes
Options options = new Options()
.createIfMissing(true)
.compressionType(CompressionType.SNAPPY);
File location = new File(storagePath);
if (!location.exists()) {
location.mkdirs();
}
File targetDB = new File(location, "data");
targetDB.mkdirs();
try {
if (useNative) {
db = JniDBFactory.factory.open(targetDB, options);
} else {
db = Iq80DBFactory.factory.open(targetDB, options);
}
isConnected = true;
if (callback != null) {
callback.on(true);
}
} catch (Exception e) {
e.printStackTrace();
if (callback != null) {
callback.on(null);
}
}
}
@Override
public void lock(Callback callback) {
if (!isConnected) {
throw new RuntimeException(_connectedError);
}
byte[] current = db.get(prefixKey);
if (current == null) {
current = new String("0").getBytes();
}
Short currentPrefix = Short.parseShort(new String(current));
db.put(prefixKey, ((currentPrefix + 1) + "").getBytes());
if (callback != null) {
Buffer newBuf = graph.newBuffer();
Base64.encodeIntToBuffer(currentPrefix, newBuf);
callback.on(newBuf);
}
}
@Override
public void unlock(Buffer previousLock, Callback callback) {
if (!isConnected) {
throw new RuntimeException(_connectedError);
}
callback.on(true);
}
}