de.zib.scalaris.operations

Class ReadOp

java.lang.Object

de.zib.scalaris.operations.ReadOp

All Implemented Interfaces:

Operation, TransactionOperation, TransactionSingleOpOperation

public class ReadOp
extends Object
implements TransactionOperation, TransactionSingleOpOperation

Operation reading a value.

Since:

3.14

Version:

3.14

Author:

Nico Kruber, kruber@zib.de

Constructor Summary

Constructors

Constructor and Description
ReadOp(OtpErlangString key) Constructor
ReadOp(String key) Constructor

Method Summary

Methods

Modifier and Type	Method and Description
OtpErlangObject	getErlang(boolean compressed) Gets the erlang representation of the operation.
OtpErlangString	getKey() Gets the key the operation is working on (if available)
OtpErlangObject	getResult() Gets the (raw Erlang) result set via Operation.setResult(OtpErlangObject, boolean).
boolean	getResultCompressed() Determines if the result set via Operation.setResult(OtpErlangObject, boolean) is compressed or not.
ErlangValue	processResult() Processes the result set by Operation.setResult(OtpErlangObject, boolean).
ErlangValue	processResultSingle() Processes the result set by Operation.setResult(OtpErlangObject, boolean) assuming that operation was committed.
void	setResult(OtpErlangObject resultRaw, boolean compressed) Sets the raw erlang result value.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ReadOp

public ReadOp(OtpErlangString key)

Constructor

Parameters:

key - the key to read

ReadOp

public ReadOp(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.

Specified by:

getErlang in interface 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

getKey

public OtpErlangString getKey()

Description copied from interface: Operation

Gets the key the operation is working on (if available)

Specified by:

getKey in interface Operation

Returns:

the key or null

setResult

public void setResult(OtpErlangObject resultRaw,
             boolean compressed)

Description copied from interface: Operation

Sets the raw erlang result value. It can be processed using Operation.processResult().

Specified by:

setResult in interface Operation

Parameters:

resultRaw - the result

compressed - whether the value inside the result is compressed or not

getResult

public OtpErlangObject getResult()

Description copied from interface: Operation

Gets the (raw Erlang) result set via Operation.setResult(OtpErlangObject, boolean).

Specified by:

getResult in interface Operation

Returns:

the result object or null if not set

getResultCompressed

public boolean getResultCompressed()

Description copied from interface: Operation

Determines if the result set via Operation.setResult(OtpErlangObject, boolean) is compressed or not.

Specified by:

getResultCompressed in interface Operation

Returns:

true if compressed, false otherwise, undefined if no result was set

processResult

public ErlangValue processResult()
                          throws NotFoundException,
                                 UnknownException

Description copied from interface: Operation

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

Specified by:

processResult in interface Operation

Returns:

a (potentially) read value (may be null)

Throws:

NotFoundException - if the requested key does not exist

UnknownException - if any other error occurs

processResultSingle

public ErlangValue processResultSingle()
                                throws NotFoundException,
                                       KeyChangedException,
                                       NotANumberException,
                                       NotAListException,
                                       AbortException,
                                       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!

Specified by:

processResultSingle in interface TransactionSingleOpOperation

Returns:

a (potentially) read value (may be null)

Throws:

NotFoundException - if the requested key does not exist

KeyChangedException - if the key did not match old_value

NotANumberException - if the previously stored value was not a number

NotAListException - if the previously stored value was no list

AbortException - if a commit failed

UnknownException - if any other error occurs

toString

public String toString()

Overrides:

toString in class Object