/**
*
* 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.client;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.concurrent.ExecutorService;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.security.User;
import org.apache.hadoop.hbase.security.UserProvider;
/**
* A non-instantiable class that manages creation of {@link Connection}s.
* Managing the lifecycle of the {@link Connection}s to the cluster is the responsibility of
* the caller.
* From a {@link Connection}, {@link Table} implementations are retrieved
* with {@link Connection#getTable(TableName)}. Example:
* <pre>
* Connection connection = ConnectionFactory.createConnection(config);
* Table table = connection.getTable(TableName.valueOf("table1"));
* try {
* // Use the table as needed, for a single operation and a single thread
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* Similarly, {@link Connection} also returns {@link Admin} and {@link RegionLocator}
* implementations.
*
* This class replaces {@link HConnectionManager}, which is now deprecated.
* @see Connection
* @since 0.99.0
*/
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class ConnectionFactory {
/** No public c.tors */
protected ConnectionFactory() {
}
/**
* Create a new Connection instance using default HBaseConfiguration. Connection
* encapsulates all housekeeping for a connection to the cluster. All tables and interfaces
* created from returned connection share zookeeper connection, meta cache, and connections
* to region servers and masters.
* <br>
* The caller is responsible for calling {@link Connection#close()} on the returned
* connection instance.
*
* Typical usage:
* <pre>
* Connection connection = ConnectionFactory.createConnection();
* Table table = connection.getTable(TableName.valueOf("mytable"));
* try {
* table.get(...);
* ...
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* @return Connection object for <code>conf</code>
*/
public static Connection createConnection() throws IOException {
return createConnection(HBaseConfiguration.create(), null, null);
}
/**
* Create a new Connection instance using the passed <code>conf</code> instance. Connection
* encapsulates all housekeeping for a connection to the cluster. All tables and interfaces
* created from returned connection share zookeeper connection, meta cache, and connections
* to region servers and masters.
* <br>
* The caller is responsible for calling {@link Connection#close()} on the returned
* connection instance.
*
* Typical usage:
* <pre>
* Connection connection = ConnectionFactory.createConnection(conf);
* Table table = connection.getTable(TableName.valueOf("mytable"));
* try {
* table.get(...);
* ...
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* @param conf configuration
* @return Connection object for <code>conf</code>
*/
public static Connection createConnection(Configuration conf) throws IOException {
return createConnection(conf, null, null);
}
/**
* Create a new Connection instance using the passed <code>conf</code> instance. Connection
* encapsulates all housekeeping for a connection to the cluster. All tables and interfaces
* created from returned connection share zookeeper connection, meta cache, and connections
* to region servers and masters.
* <br>
* The caller is responsible for calling {@link Connection#close()} on the returned
* connection instance.
*
* Typical usage:
* <pre>
* Connection connection = ConnectionFactory.createConnection(conf);
* Table table = connection.getTable(TableName.valueOf("mytable"));
* try {
* table.get(...);
* ...
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* @param conf configuration
* @param pool the thread pool to use for batch operations
* @return Connection object for <code>conf</code>
*/
public static Connection createConnection(Configuration conf, ExecutorService pool)
throws IOException {
return createConnection(conf, pool, null);
}
/**
* Create a new Connection instance using the passed <code>conf</code> instance. Connection
* encapsulates all housekeeping for a connection to the cluster. All tables and interfaces
* created from returned connection share zookeeper connection, meta cache, and connections
* to region servers and masters.
* <br>
* The caller is responsible for calling {@link Connection#close()} on the returned
* connection instance.
*
* Typical usage:
* <pre>
* Connection connection = ConnectionFactory.createConnection(conf);
* Table table = connection.getTable(TableName.valueOf("table1"));
* try {
* table.get(...);
* ...
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* @param conf configuration
* @param user the user the connection is for
* @return Connection object for <code>conf</code>
*/
public static Connection createConnection(Configuration conf, User user)
throws IOException {
return createConnection(conf, null, user);
}
/**
* Create a new Connection instance using the passed <code>conf</code> instance. Connection
* encapsulates all housekeeping for a connection to the cluster. All tables and interfaces
* created from returned connection share zookeeper connection, meta cache, and connections
* to region servers and masters.
* <br>
* The caller is responsible for calling {@link Connection#close()} on the returned
* connection instance.
*
* Typical usage:
* <pre>
* Connection connection = ConnectionFactory.createConnection(conf);
* Table table = connection.getTable(TableName.valueOf("table1"));
* try {
* table.get(...);
* ...
* } finally {
* table.close();
* connection.close();
* }
* </pre>
*
* @param conf configuration
* @param user the user the connection is for
* @param pool the thread pool to use for batch operations
* @return Connection object for <code>conf</code>
*/
public static Connection createConnection(Configuration conf, ExecutorService pool, User user)
throws IOException {
if (user == null) {
UserProvider provider = UserProvider.instantiate(conf);
user = provider.getCurrent();
}
return createConnection(conf, false, pool, user);
}
static Connection createConnection(final Configuration conf, final boolean managed,
final ExecutorService pool, final User user)
throws IOException {
String className = conf.get(HConnection.HBASE_CLIENT_CONNECTION_IMPL,
ConnectionManager.HConnectionImplementation.class.getName());
Class<?> clazz = null;
try {
clazz = Class.forName(className);
} catch (ClassNotFoundException e) {
throw new IOException(e);
}
try {
// Default HCM#HCI is not accessible; make it so before invoking.
Constructor<?> constructor =
clazz.getDeclaredConstructor(Configuration.class,
boolean.class, ExecutorService.class, User.class);
constructor.setAccessible(true);
return (Connection) constructor.newInstance(conf, managed, pool, user);
} catch (Exception e) {
throw new IOException(e);
}
}
}