de.zib.scalaris.executor
Class ScalarisReadOp

java.lang.Object
  de.zib.scalaris.executor.ScalarisReadOp

All Implemented Interfaces:

ScalarisOp

public class ScalarisReadOp
extends Object
implements ScalarisOp

Implements a read operation (tolerates "not found" and in this case contains null).

Since:

3.13

Version:

3.13

Author:

Nico Kruber, kruber@zib.de

Constructor Summary

ScalarisReadOp(String key)
Creates a read operation.

Method Summary

int	doPhase(int phase, int firstOp, ResultList results, RequestList requests) Executes the given phase.
String	getKey() Gets the key to read from.
ErlangValue	getValue() Gets the value from the read.
String	toString()
int	workPhases() Gets the number of work phases needed by this operation (not including the final result verification phase).

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ScalarisReadOp

public ScalarisReadOp(String key)

Creates a read operation.

Parameters:

key - the key to read from

Method Detail

workPhases

public int workPhases()

Description copied from interface: ScalarisOp

Gets the number of work phases needed by this operation (not including the final result verification phase).

Specified by:

workPhases in interface ScalarisOp

Returns:

number of required phases

doPhase

public final int doPhase(int phase,
                         int firstOp,
                         ResultList results,
                         RequestList requests)
                  throws OtpErlangException,
                         UnknownException,
                         IllegalArgumentException

Description copied from interface: ScalarisOp

Executes the given phase.

Specified by:

doPhase in interface ScalarisOp

Parameters:

phase - the number of the current phase

firstOp - the current operation's index in the result list

results - the results from the previous operations (may be null if there was none)

requests - the requests for the next operations (may be null if there are none, i.e. in the verification phase)

Returns:

the number of processed operations from the results list

Throws:

OtpErlangException - if an error occured verifying a result from previous operations

UnknownException - if an error occured verifying a result from previous operations

IllegalArgumentException - if the given work phase is not supported

See Also:

ScalarisOp.workPhases()

toString

public String toString()

Specified by:

toString in interface ScalarisOp

Overrides:

toString in class Object

getKey

public String getKey()

Gets the key to read from.

Returns:

the key

getValue

public ErlangValue getValue()

Gets the value from the read.

Returns:

the value that has been read (may be null