weka.knowledgeflow

Class Data

java.lang.Object

weka.knowledgeflow.Data

All Implemented Interfaces:

Serializable

public class Data
extends Object
implements Serializable

Class for encapsulating data to be transferred between Knowledge Flow steps over a particular connection type. Typical usage involves constructing a Data object with a given connection name and then setting one or more pieces of "payload" data to encapsulate. Usually there is a primary payload that is associated with the connection name itself (there is a constructor that takes both the connection name and the primary payload data). Further auxiliary data items can be added via the setPayloadElement() method.

Standard connection types are defined as constants in the StepManager class. There is nothing to prevent clients from using their own connection types (as these are just string identifiers).

Typical usage in a client step (transferring an training instances object):

     Instances train = ...
     Data myData = new Data(StepManager.CON_TRAININGSET, train);
     getStepManager().outputData(myData);
 

Version:

$Revision: $

Author:

mhall{[at]}pentaho{[dot]}com

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
Data() Empty constructor - no connection name; no payload
Data(String connectionName) Construct a Data object with just a connection name
Data(String connectionName, Object primaryPayload) Construct a Data object with a connection name and a primary payload object to associate with the connection name

Method Summary

Modifier and Type	Method and Description
void	clearPayload() Clear all payload elements from this Data object
String	getConnectionName() Get the connection name associated with this Data object
<T> T	getPayloadElement(String name) Get a payload element from this Data object.
<T> T	getPayloadElement(String name, T defaultValue) Get a payload element from this Data object.
<T> T	getPrimaryPayload() Get the primary payload of this data object (i.e.
Step	getSourceStep() Get the source step producing this Data object
void	setConnectionName(String name) Set the connection name for this Data object
void	setPayloadElement(String name, Object value) Set a payload element to encapsulate in this Data object.
void	setSourceStep(Step sourceStep) Set the source step of producing this Data object

Methods inherited from class java.lang.Object

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

Constructor Detail

Data

public Data()

Empty constructor - no connection name; no payload

Data

public Data(String connectionName)

Construct a Data object with just a connection name

Parameters:

connectionName - the connection name

Data

public Data(String connectionName,
            Object primaryPayload)

Construct a Data object with a connection name and a primary payload object to associate with the connection name

Parameters:

connectionName - connection name

primaryPayload - primary payload object (i.e. is keyed against the connection name)

Method Detail

setSourceStep

public void setSourceStep(Step sourceStep)

Set the source step of producing this Data object

Parameters:

sourceStep - the source step

getSourceStep

public Step getSourceStep()

Get the source step producing this Data object

Returns:

the source step producing the data object

setConnectionName

public void setConnectionName(String name)

Set the connection name for this Data object

Parameters:

name - the name of the connection

getConnectionName

public String getConnectionName()

Get the connection name associated with this Data object

Returns:

the connection name

getPrimaryPayload

public <T> T getPrimaryPayload()

Get the primary payload of this data object (i.e. the data associated with the connection name)

Type Parameters:

T - the type of the primary payload

Returns:

the primary payload data (or null if there is no data associated with the connection)

getPayloadElement

public <T> T getPayloadElement(String name)

Get a payload element from this Data object. Standard payload element names (keys) can be found as constants defined in the StepManager class.

Parameters:

name - the name of the payload element to get

Returns:

the named payload element, or null if it does not exist in this Data object

getPayloadElement

public <T> T getPayloadElement(String name,
                               T defaultValue)

Get a payload element from this Data object. Standard payload element names (keys) can be found as constants defined in the StepManager class.

Type Parameters:

T - the type of the payload element to get

Parameters:

name - the name of the payload element to get

defaultValue - a default value if the named element does not exist

Returns:

the payload element, or the supplied default value.

setPayloadElement

public void setPayloadElement(String name,
                              Object value)

Set a payload element to encapsulate in this Data object. Standard payload element names (keys) can be found as constants defined in the StepManager class.

Parameters:

name - the name of the payload element to encapsulate

value - the value of the payload element

clearPayload

public void clearPayload()

Clear all payload elements from this Data object