/**
* 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 com.alibaba.wasp.fserver;
import com.alibaba.wasp.EntityGroupInfo;
import com.alibaba.wasp.GlobalEntityGroupInfo;
import com.alibaba.wasp.NotServingEntityGroupException;
import com.alibaba.wasp.plan.action.ScanAction;
import com.alibaba.wasp.storage.StorageTableNotFoundException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import java.io.Closeable;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Execute global query plan.
*
*/
public class GlobalEntityGroup implements Closeable, EntityGroupServices {
public static final Log LOG = LogFactory.getLog(GlobalEntityGroup.class);
protected final FServerServices services;
protected Configuration configuration;
private final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
final AtomicBoolean close = new AtomicBoolean(false);
final GlobalEntityGroupInfo entityGroupInfo;
public GlobalEntityGroup(FServerServices service) {
this.services = service;
this.configuration = service.getConfiguration();
this.entityGroupInfo = new GlobalEntityGroupInfo();
}
/**
* Return an iterator that scans over the EntityGroup, returning the indicated
* columns and rows specified by the
*
* <p>
* This Iterator must be closed by the caller.
*
* @param action
* @return
* @throws java.io.IOException
* @throws com.alibaba.wasp.storage.StorageTableNotFoundException
*/
public EntityGroupScanner getScanner(ScanAction action) throws IOException,
StorageTableNotFoundException {
startEntityGroupOperation();
try {
return instantiateEntityGroupScanner(action);
} finally {
closeEntityGroupOperation();
}
}
/**
* return EntityGroupScanner.
*
* @param action
* @return
* @throws java.io.IOException
* @throws com.alibaba.wasp.storage.StorageTableNotFoundException
*/
protected EntityGroupScanner instantiateEntityGroupScanner(ScanAction action)
throws StorageTableNotFoundException, IOException {
return new EntityGroupScanner(this, action, System.currentTimeMillis());
}
/**
* This method needs to be called before any public call that reads or
* modifies data. It has to be called just before a try. Acquires checks if
* the entityGroup is close.
*
* @throws com.alibaba.wasp.NotServingEntityGroupException
* when the entityGroup is closing or closed
*/
private void startEntityGroupOperation()
throws NotServingEntityGroupException {
lock.readLock().lock();
if (this.close.get()) {
lock.readLock().unlock();
throw new NotServingEntityGroupException("GlobalEntityGroup is closed");
}
}
private void closeEntityGroupOperation() {
lock.readLock().unlock();
}
@Override
public void close() {
close.set(true);
}
/**
* @see org.apache.hadoop.conf.Configurable#getConf()
*/
@Override
public Configuration getConf() {
return this.configuration;
}
/**
* @see com.alibaba.wasp.fserver.EntityGroupServices#getFServerServices()
*/
@Override
public FServerServices getFServerServices() {
return this.services;
}
/**
* @see com.alibaba.wasp.fserver.EntityGroupServices#getEntityGroupInfo()
*/
@Override
public EntityGroupInfo getEntityGroupInfo() {
return entityGroupInfo;
}
}