Package weka.knowledgeflow.steps

Class FlowByExpression

  • All Implemented Interfaces:
    java.io.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:
    Serialized Form

    • Constructor Detail

      • FlowByExpression

        public FlowByExpression()

    • Method Detail

      • setExpressionString

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

      • getExpressionString

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

      • setTrueStepName

        public void setTrueStepName​(java.lang.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 java.lang.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​(java.lang.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 java.lang.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 java.util.List<java.lang.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 java.util.List<java.lang.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 java.util.List<java.lang.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​(java.lang.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

      • getCustomEditorForStep

        public java.lang.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