// Copyright 2012,2013 Vaughn Vernon
//
// 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 com.saasovation.common.port.adapter.persistence.leveldb;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.iq80.leveldb.DB;
import org.iq80.leveldb.DBFactory;
import org.iq80.leveldb.DBIterator;
import org.iq80.leveldb.Options;
import org.iq80.leveldb.impl.Iq80DBFactory;
import com.saasovation.common.event.sourcing.EventStoreException;
public class LevelDBProvider {
private static LevelDBProvider instance;
private Map<String,DB> databases;
public static synchronized LevelDBProvider instance() {
if (instance == null) {
instance = new LevelDBProvider();
}
return instance;
}
public void close(String aDirectoryPath) {
synchronized (this.databases) {
DB db = this.databases.get(aDirectoryPath);
if (db != null) {
this.databases.remove(aDirectoryPath);
try {
db.close();
} catch (IOException e) {
throw new IllegalStateException(
"Cannot completely close LevelDB database: "
+ aDirectoryPath
+ " because: "
+ e.getMessage(),
e);
}
}
}
}
public void closeAll() {
List<String> directoryPaths =
new ArrayList<String>(this.databases.keySet());
for (String directoryPath : directoryPaths) {
this.close(directoryPath);
}
}
public DB databaseFrom(String aDirectoryPath) {
DB db = null;
synchronized (this.databases) {
db = this.databases.get(aDirectoryPath);
if (db == null) {
db = this.openDatabase(aDirectoryPath);
this.databases.put(aDirectoryPath, db);
}
}
return db;
}
public void purge(DB aDatabase) {
DBIterator iterator = aDatabase.iterator();
try {
iterator.seekToFirst();
while (iterator.hasNext()) {
Entry<byte[],byte[]> entry = iterator.next();
aDatabase.delete(entry.getKey());
}
} catch (Throwable t) {
throw new EventStoreException(
"Cannot purge LevelDB database: because: "
+ t.getMessage(),
t);
} finally {
try {
iterator.close();
} catch (Throwable t) {
// ignore
}
}
}
private LevelDBProvider() {
super();
this.databases = new HashMap<String,DB>();
}
private DB openDatabase(String aDirectoryPath) {
try {
DBFactory factory = new Iq80DBFactory();
Options options = new Options();
options.createIfMissing(true);
DB db = factory.open(new File(aDirectoryPath), options);
return db;
} catch (Throwable t) {
throw new IllegalStateException(
"Cannot open LevelDB database: "
+ aDirectoryPath
+ " because: "
+ t.getMessage(),
t);
}
}
}