Package weka.knowledgeflow.steps

Class FlowByExpression

java.lang.Object
weka.knowledgeflow.steps.BaseStep
weka.knowledgeflow.steps.FlowByExpression
All Implemented Interfaces:
Serializable, BaseStepExtender, Step
@KFStep(name="FlowByExpression", category="Flow", toolTipText="Route instances according to the evaluation of a logical expression. The expression can test the values of one or more incoming attributes. The test can involve constants or comparing one attribute\'s values to another. Inequalities along with string operations such as contains, starts-with, ends-with and regular expressions may be used as operators. \"True\" instances can be sent to one downstream step and \"False\" instances sent to another.", iconPath="weka/gui/knowledgeflow/icons/FlowByExpression.png") public class FlowByExpression extends BaseStep
A step that splits incoming instances (or instance streams) according to the evaluation of a logical expression. The expression can test the values of one or more incoming attributes. The test can involve constants or comparing one attribute's values to another. Inequalities along with string operations such as contains, starts-with, ends-with and regular expressions may be used as operators.
Version:
$Revision: $
Author:
Mark Hall (mhall{[at]}pentaho{[dot]}com)
See Also:

  • Constructor Details

    • FlowByExpression

      public FlowByExpression()

  • Method Details

    • setExpressionString

      public void setExpressionString(String expressionString)
      Set the expression (in internal format)
      Parameters:
      expressionString - the expression to use (in internal format)

    • getExpressionString

      public String getExpressionString()
      Get the current expression (in internal format)
      Returns:
      the current expression (in internal format)

    • setTrueStepName

      public void setTrueStepName(String trueStep)
      Set the name of the connected step to send "true" instances to
      Parameters:
      trueStep - the name of the step to send "true" instances to

    • getTrueStepName

      public String getTrueStepName()
      Get the name of the connected step to send "true" instances to
      Returns:
      the name of the step to send "true" instances to

    • setFalseStepName

      public void setFalseStepName(String falseStep)
      Set the name of the connected step to send "false" instances to
      Parameters:
      falseStep - the name of the step to send "false" instances to

    • getFalseStepName

      public String getFalseStepName()
      Get the name of the connected step to send "false" instances to
      Returns:
      the name of the step to send "false" instances to

    • getDownstreamStepNames

      public List<String> getDownstreamStepNames()
      Get a list of the names of connected downstream steps
      Returns:
      a list of the names of connected downstream steps

    • stepInit

      public void stepInit() throws WekaException
      Initialize the step.
      Throws:
      WekaException - if a problem occurs during initialization

    • getIncomingConnectionTypes

      public List<String> getIncomingConnectionTypes()
      Get a list of incoming connection types that this step can accept. Ideally (and if appropriate), this should take into account the state of the step and any existing incoming connections. E.g. a step might be able to accept one (and only one) incoming batch data connection.
      Returns:
      a list of incoming connections that this step can accept given its current state

    • getOutgoingConnectionTypes

      public List<String> getOutgoingConnectionTypes()
      Get a list of outgoing connection types that this step can produce. Ideally (and if appropriate), this should take into account the state of the step and the incoming connections. E.g. depending on what incoming connection is present, a step might be able to produce a trainingSet output, a testSet output or neither, but not both.
      Returns:
      a list of outgoing connections that this step can produce

    • outputStructureForConnectionType

      public Instances outputStructureForConnectionType(String connectionName) throws WekaException
      If possible, get the output structure for the named connection type as a header-only set of instances. Can return null if the specified connection type is not representable as Instances or cannot be determined at present.
      Specified by:
      outputStructureForConnectionType in interface Step
      Overrides:
      outputStructureForConnectionType in class BaseStep
      Parameters:
      connectionName - the name of the connection type to get the output structure for
      Returns:
      the output structure as a header-only Instances object
      Throws:
      WekaException - if a problem occurs

    • processIncoming

      public void processIncoming(Data data) throws WekaException
      Main processing routine
      Specified by:
      processIncoming in interface BaseStepExtender
      Specified by:
      processIncoming in interface Step
      Overrides:
      processIncoming in class BaseStep
      Parameters:
      data - incoming data object
      Throws:
      WekaException - if a problem occurs

    • getCustomEditorForStep

      public String getCustomEditorForStep()
      Return the fully qualified name of a custom editor component (JComponent) to use for editing the properties of the step. This method can return null, in which case the system will dynamically generate an editor using the GenericObjectEditor
      Specified by:
      getCustomEditorForStep in interface Step
      Overrides:
      getCustomEditorForStep in class BaseStep
      Returns:
      the fully qualified name of a step editor component