/*
* Copyright 2009 The Apache Software Foundation
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.hadoop.hbase.stargate;
import java.io.IOException;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.HTablePool;
import com.sun.jersey.server.impl.container.servlet.ServletAdaptor;
/**
* Singleton class encapsulating global REST servlet state and functions.
*/
public class RESTServlet extends ServletAdaptor {
private static final long serialVersionUID = 1L;
public static final int DEFAULT_MAX_AGE = 60 * 60 * 4; // 4 hours
public static final String VERSION_STRING = "0.0.1";
private static RESTServlet instance;
private transient final HBaseConfiguration conf;
private transient final HTablePool pool;
protected Map<String,Integer> maxAgeMap =
Collections.synchronizedMap(new HashMap<String,Integer>());
/**
* @return the RESTServlet singleton instance
* @throws IOException
*/
public synchronized static RESTServlet getInstance() throws IOException {
if (instance == null) {
instance = new RESTServlet();
}
return instance;
}
/**
* Constructor
* @throws IOException
*/
public RESTServlet() throws IOException {
this.conf = new HBaseConfiguration();
this.pool = new HTablePool(conf, 10);
}
/**
* Get a table pool for the given table.
* @return the table pool
*/
protected HTablePool getTablePool() {
return pool;
}
/**
* @return the servlet's global HBase configuration
*/
protected HBaseConfiguration getConfiguration() {
return conf;
}
/**
* @param tableName the table name
* @return the maximum cache age suitable for use with this table, in
* seconds
* @throws IOException
*/
public int getMaxAge(String tableName) throws IOException {
Integer i = maxAgeMap.get(tableName);
if (i != null) {
return i.intValue();
}
HTable table = pool.getTable(tableName);
try {
int maxAge = DEFAULT_MAX_AGE;
for (HColumnDescriptor family :
table.getTableDescriptor().getFamilies()) {
int ttl = family.getTimeToLive();
if (ttl < 0) {
continue;
}
if (ttl < maxAge) {
maxAge = ttl;
}
}
maxAgeMap.put(tableName, maxAge);
return maxAge;
} finally {
pool.putTable(table);
}
}
/**
* Signal that a previously calculated maximum cache age has been
* invalidated by a schema change.
* @param tableName the table name
*/
public void invalidateMaxAge(String tableName) {
maxAgeMap.remove(tableName);
}
}