de.zib.scalaris.operations
Class ReadRandomFromListOp

java.lang.Object
  de.zib.scalaris.operations.PartialReadOp
      de.zib.scalaris.operations.ReadRandomFromListOp

All Implemented Interfaces:

Operation, TransactionOperation, TransactionSingleOpOperation

public class ReadRandomFromListOp
extends PartialReadOp

Operation reading a random entry from a (non-empty) list value.

Since:

3.18

Version:

3.18

Author:

Nico Kruber, kruber@zib.de

Nested Class Summary

static class

ReadRandomFromListOp.Result Result type of random_from_list operations.

Constructor Summary

ReadRandomFromListOp(OtpErlangString key)
Constructor

ReadRandomFromListOp(String key)
Constructor

Method Summary

OtpErlangObject	getErlang(boolean compressed) Gets the erlang representation of the operation.
ReadRandomFromListOp.Result	processResult() Processes the result set by Operation.setResult(OtpErlangObject, boolean).
ReadRandomFromListOp.Result	processResultSingle() Processes the result set by Operation.setResult(OtpErlangObject, boolean) assuming that operation was committed.
String	toString()

Methods inherited from class de.zib.scalaris.operations.PartialReadOp

getKey, getResult, getResultCompressed, setResult

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadRandomFromListOp

public ReadRandomFromListOp(OtpErlangString key)

Constructor

Parameters:

key - the key to read

ReadRandomFromListOp

public ReadRandomFromListOp(String key)

Constructor

Parameters:

key - the key to read

Method Detail

getErlang

public OtpErlangObject getErlang(boolean compressed)

Description copied from interface: Operation

Gets the erlang representation of the operation.

Parameters:

compressed - whether the value part in the term should be encoded, i.e. compressed into an Erlang binary, or not

Returns:

erlang representation for api_tx:req_list

processResult

public ReadRandomFromListOp.Result processResult()
                                          throws NotFoundException,
                                                 EmptyListException,
                                                 NotAListException,
                                                 UnknownException

Description copied from interface: Operation

Processes the result set by Operation.setResult(OtpErlangObject, boolean). Note: the created value is not cached!

Returns:

a (potentially) read value (may be null)

Throws:

NotFoundException - if the requested key does not exist

EmptyListException - if the stored value is an empty list but the op requires a non-empty list

NotAListException - if the previously stored value was no list

UnknownException - if any other error occurs

processResultSingle

public ReadRandomFromListOp.Result processResultSingle()
                                                throws NotFoundException,
                                                       EmptyListException,
                                                       NotAListException,
                                                       UnknownException

Description copied from interface: TransactionSingleOpOperation

Processes the result set by Operation.setResult(OtpErlangObject, boolean) assuming that operation was committed. In contrast to Operation.processResult() operations like WriteOp will throw a proper AbortException for their commit part instead of an UnknownException. Note: the created value is not cached!

Returns:

a (potentially) read value (may be null)

Throws:

NotFoundException - if the requested key does not exist

EmptyListException - if the stored value is an empty list but the op requires a non-empty list

NotAListException - if the previously stored value was no list

UnknownException - if any other error occurs

toString

public String toString()

Overrides:

toString in class Object