org.apache.hadoop.hbase.client

接口 Connection

所有超级接口:

Abortable, AutoCloseable, Closeable

所有已知子接口:

ClusterConnection, HConnection

@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface Connection
extends Abortable, Closeable

A cluster connection encapsulating lower level individual connections to actual servers and a connection to zookeeper. Connections are instantiated through the ConnectionFactory class. The lifecycle of the connection is managed by the caller, who has to close() the connection to release the resources.

The connection object contains logic to find the master, locate regions out on the cluster, keeps a cache of locations and then knows how to re-calibrate after they move. The individual connections to servers, meta cache, zookeeper connection, etc are all shared by the Table and Admin instances obtained from this connection.

Connection creation is a heavy-weight operation. Connection implementations are thread-safe, so that the client can create a connection once, and share it with different threads. Table and Admin instances, on the other hand, are light-weight and are not thread-safe. Typically, a single connection per client application is instantiated and every thread will obtain its own Table instance. Caching or pooling of Table and Admin is not recommended.

This class replaces HConnection, which is now deprecated.

从以下版本开始:

0.99.0

另请参阅:

ConnectionFactory

方法概要

方法

限定符和类型	方法和说明
void	close()
Admin	getAdmin() Retrieve an Admin implementation to administer an HBase cluster.
BufferedMutator	getBufferedMutator(BufferedMutatorParams params) Retrieve a BufferedMutator for performing client-side buffering of writes.
BufferedMutator	getBufferedMutator(TableName tableName) Retrieve a BufferedMutator for performing client-side buffering of writes.
String	getClusterId()
org.apache.hadoop.conf.Configuration	getConfiguration()
RegionLocator	getRegionLocator(TableName tableName) Retrieve a RegionLocator implementation to inspect region information on a table.
Table	getTable(TableName tableName) Retrieve a Table implementation for accessing a table.
Table	getTable(TableName tableName, ExecutorService pool) Retrieve a Table implementation for accessing a table.
boolean	isClosed() Returns whether the connection is closed or not.

从接口继承的方法 org.apache.hadoop.hbase.Abortable

abort, isAborted

方法详细资料

getConfiguration

org.apache.hadoop.conf.Configuration getConfiguration()

返回:

Configuration instance being used by this Connection instance.

getTable

Table getTable(TableName tableName)
               throws IOException

Retrieve a Table implementation for accessing a table. The returned Table is not thread safe, a new instance should be created for each using thread. This is a lightweight operation, pooling or caching of the returned Table is neither required nor desired.

The caller is responsible for calling Table.close() on the returned table instance.

Since 0.98.1 this method no longer checks table existence. An exception will be thrown if the table does not exist only when the first operation is attempted.

参数:

tableName - the name of the table

返回:

a Table to use for interactions with this table

抛出:

IOException

getTable

Table getTable(TableName tableName,
             ExecutorService pool)
               throws IOException

Retrieve a Table implementation for accessing a table. The returned Table is not thread safe, a new instance should be created for each using thread. This is a lightweight operation, pooling or caching of the returned Table is neither required nor desired.

The caller is responsible for calling Table.close() on the returned table instance.

Since 0.98.1 this method no longer checks table existence. An exception will be thrown if the table does not exist only when the first operation is attempted.

参数:

tableName - the name of the table

pool - The thread pool to use for batch operations, null to use a default pool.

返回:

a Table to use for interactions with this table

抛出:

IOException

getBufferedMutator

BufferedMutator getBufferedMutator(TableName tableName)
                                   throws IOException

Retrieve a BufferedMutator for performing client-side buffering of writes. The BufferedMutator returned by this method is thread-safe. This BufferedMutator will use the Connection's ExecutorService. This object can be used for long lived operations.

The caller is responsible for calling BufferedMutator.close() on the returned BufferedMutator instance.

This accessor will use the connection's ExecutorService and will throw an exception in the main thread when an asynchronous exception occurs.

参数:

tableName - the name of the table

返回:

a BufferedMutator for the supplied tableName.

抛出:

IOException

getBufferedMutator

BufferedMutator getBufferedMutator(BufferedMutatorParams params)
                                   throws IOException

Retrieve a BufferedMutator for performing client-side buffering of writes. The BufferedMutator returned by this method is thread-safe. This object can be used for long lived table operations. The caller is responsible for calling BufferedMutator.close() on the returned BufferedMutator instance.

参数:

params - details on how to instantiate the BufferedMutator.

返回:

a BufferedMutator for the supplied tableName.

抛出:

IOException

getRegionLocator

RegionLocator getRegionLocator(TableName tableName)
                               throws IOException

Retrieve a RegionLocator implementation to inspect region information on a table. The returned RegionLocator is not thread-safe, so a new instance should be created for each using thread. This is a lightweight operation. Pooling or caching of the returned RegionLocator is neither required nor desired.
The caller is responsible for calling Closeable.close() on the returned RegionLocator instance. RegionLocator needs to be unmanaged

参数:

tableName - Name of the table who's region is to be examined

返回:

A RegionLocator instance

抛出:

IOException

getAdmin

Admin getAdmin()
               throws IOException

Retrieve an Admin implementation to administer an HBase cluster. The returned Admin is not guaranteed to be thread-safe. A new instance should be created for each using thread. This is a lightweight operation. Pooling or caching of the returned Admin is not recommended.
The caller is responsible for calling Admin.close() on the returned Admin instance.

返回:

an Admin instance for cluster administration

抛出:

IOException

getClusterId

String getClusterId()
                    throws IOException

返回:

the cluster ID unique to this HBase cluster.

抛出:

IOException

close

void close()
           throws IOException

指定者:

close 在接口中 AutoCloseable

指定者:

close 在接口中 Closeable

抛出:

IOException

isClosed

boolean isClosed()

Returns whether the connection is closed or not.

返回:

true if this connection is closed