org.apache.hadoop.hbase.client

Class RegionServerCallable<T,S>

java.lang.Object

org.apache.hadoop.hbase.client.RegionServerCallable<T,S>

Type Parameters:

T - The class that the ServerCallable handles.

S - The protocol to use (Admin or Client or even an Endpoint over in MetaTableAccessor).

All Implemented Interfaces:

RetryingCallable<T>

Direct Known Subclasses:

ClientServiceCallable

@InterfaceAudience.Private
public abstract class RegionServerCallable<T,S>
extends Object
implements RetryingCallable<T>

Implementations make a RPC call against a RegionService via a protobuf Service. Implement rpcCall() and the parent class setClientByServiceName; this latter is where the RPC stub gets set (the appropriate protobuf 'Service'/Client). Be sure to make use of the RpcController that this instance is carrying via #getRpcController().

TODO: this class is actually tied to one region, because most of the paths make use of the regioninfo part of location when building requests. The only reason it works for multi-region requests (e.g. batch) is that they happen to not use the region parts. This could be done cleaner (e.g. having a generic parameter and 2 derived classes, RegionCallable and actual RegionServerCallable with ServerName.

Field Summary

Fields

Modifier and Type	Field and Description
protected HRegionLocation	location Some subclasses want to set their own location.
protected org.apache.hbase.thirdparty.com.google.protobuf.RpcController	rpcController This is 99% of the time a HBaseRpcController but also used doing Coprocessor Endpoints and in this case, it is a ServerRpcControllable which is not a HBaseRpcController.
protected S	stub

Constructor Summary

Constructors

Constructor and Description
RegionServerCallable(Connection connection, TableName tableName, byte[] row, org.apache.hbase.thirdparty.com.google.protobuf.RpcController rpcController)
RegionServerCallable(Connection connection, TableName tableName, byte[] row, org.apache.hbase.thirdparty.com.google.protobuf.RpcController rpcController, int priority)

Method Summary

Modifier and Type	Method and Description
T	call(int callTimeout) Override that changes call Exception from Exception to IOException.
protected ClusterConnection	getConnection()
String	getExceptionMessageAdditionalDetail()
HRegionInfo	getHRegionInfo()
protected HRegionLocation	getLocation()
protected int	getPriority()
byte[]	getRow()
protected org.apache.hbase.thirdparty.com.google.protobuf.RpcController	getRpcController()
protected CellScanner	getRpcControllerCellScanner() Get the RpcController CellScanner.
protected S	getStub()
TableName	getTableName()
void	prepare(boolean reload) Prepare by setting up any connections to servers, etc., ahead of call invocation.
protected abstract T	rpcCall() Run the RPC call.
protected void	setLocation(HRegionLocation location)
protected void	setRpcControllerCellScanner(CellScanner cellScanner)
protected void	setStub(S stub)
protected abstract void	setStubByServiceName(ServerName serviceName) Set the RCP client stub
long	sleep(long pause, int tries)
void	throwable(Throwable t, boolean retrying) Called when call throws an exception and we are going to retry; take action to make it so we succeed on next call (clear caches, do relookup of locations, etc.).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

location

protected HRegionLocation location

Some subclasses want to set their own location. Make it protected.

stub

protected S stub

rpcController

protected final org.apache.hbase.thirdparty.com.google.protobuf.RpcController rpcController

This is 99% of the time a HBaseRpcController but also used doing Coprocessor Endpoints and in this case, it is a ServerRpcControllable which is not a HBaseRpcController. Can be null!

Constructor Detail

RegionServerCallable

public RegionServerCallable(Connection connection,
                            TableName tableName,
                            byte[] row,
                            org.apache.hbase.thirdparty.com.google.protobuf.RpcController rpcController)

Parameters:

connection - Connection to use.

rpcController - Controller to use; can be shaded or non-shaded.

tableName - Table name to which row belongs.

row - The row we want in tableName.

RegionServerCallable

public RegionServerCallable(Connection connection,
                            TableName tableName,
                            byte[] row,
                            org.apache.hbase.thirdparty.com.google.protobuf.RpcController rpcController,
                            int priority)

Method Detail

getRpcController

protected org.apache.hbase.thirdparty.com.google.protobuf.RpcController getRpcController()

setStub

protected void setStub(S stub)

getStub

protected S getStub()

call

public T call(int callTimeout)
       throws IOException

Override that changes call Exception from Exception to IOException. Also does set up of the rpcController.

Specified by:

call in interface RetryingCallable<T>

Parameters:

callTimeout - - the time available for this call. 0 for infinite.

Returns:

computed result

Throws:

IOException

rpcCall

protected abstract T rpcCall()
                      throws Exception

Run the RPC call. Implement this method. To get at the rpcController that has been created and configured to make this rpc call, use getRpcController(). We are trying to contain rpcController references so we don't pollute codebase with protobuf references; keep the protobuf references contained and only present in a few classes rather than all about the code base.

Throws:

Exception

getRpcControllerCellScanner

protected CellScanner getRpcControllerCellScanner()

Get the RpcController CellScanner. If the RpcController is a HBaseRpcController, which it is in all cases except when we are processing Coprocessor Endpoint, then this method returns a reference to the CellScanner that the HBaseRpcController is carrying. Do it up here in this Callable so we don't have to scatter ugly instanceof tests around the codebase. Will return null if called in a Coproccessor Endpoint context. Should never happen.

setRpcControllerCellScanner

protected void setRpcControllerCellScanner(CellScanner cellScanner)

getConnection

protected ClusterConnection getConnection()

Returns:

ClusterConnection instance used by this Callable.

getLocation

protected HRegionLocation getLocation()

setLocation

protected void setLocation(HRegionLocation location)

getTableName

public TableName getTableName()

getRow

public byte[] getRow()

getPriority

protected int getPriority()

throwable

public void throwable(Throwable t,
                      boolean retrying)

Description copied from interface: RetryingCallable

Called when call throws an exception and we are going to retry; take action to make it so we succeed on next call (clear caches, do relookup of locations, etc.).

Specified by:

throwable in interface RetryingCallable<T>

Parameters:

t - throwable which was thrown

retrying - True if we are in retrying mode (we are not in retrying mode when max retries == 1; we ARE in retrying mode if retries > 1 even when we are the last attempt)

getExceptionMessageAdditionalDetail

public String getExceptionMessageAdditionalDetail()

Specified by:

getExceptionMessageAdditionalDetail in interface RetryingCallable<T>

Returns:

Some details from the implementation that we would like to add to a terminating exception; i.e. a fatal exception is being thrown ending retries and we might like to add more implementation-specific detail on to the exception being thrown.

sleep

public long sleep(long pause,
                  int tries)

Specified by:

sleep in interface RetryingCallable<T>

Parameters:

pause - time to pause

tries - amount of tries until till sleep

Returns:

Suggestion on how much to sleep between retries

getHRegionInfo

public HRegionInfo getHRegionInfo()

Returns:

the HRegionInfo for the current region

prepare

public void prepare(boolean reload)
             throws IOException

Description copied from interface: RetryingCallable

Prepare by setting up any connections to servers, etc., ahead of call invocation. TODO: We call prepare before EVERY call. Seems wrong. FIX!!!!

Specified by:

prepare in interface RetryingCallable<T>

Parameters:

reload - Set this to true if need to requery locations

Throws:

IOException - e

setStubByServiceName

protected abstract void setStubByServiceName(ServerName serviceName)
                                      throws IOException

Set the RCP client stub

Parameters:

serviceName - to get the rpc stub for

Throws:

IOException - When client could not be created