weka.core.pmml

## Class Expression

- java.lang.Object
- - weka.core.pmml.Expression

- All Implemented Interfaces:
    java.io.Serializable
  Direct Known Subclasses:
    Constant, Discretize, FieldRef, NormContinuous, NormDiscrete

      public abstract class Expression
      extends java.lang.Object
      implements java.io.Serializable

  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `Expression(FieldMetaInfo.Optype opType, java.util.ArrayList<Attribute> fieldDefs)`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `static Expression` | `getExpression(org.w3c.dom.Node container, FieldMetaInfo.Optype opType, java.util.ArrayList<Attribute> fieldDefs, weka.core.pmml.TransformationDictionary transDict)` Static factory method that returns a subclass of Expression that encapsulates the type of expression contained in the Element supplied.
    `static Expression` | `getExpression(java.lang.String name, org.w3c.dom.Node expression, FieldMetaInfo.Optype opType, java.util.ArrayList<Attribute> fieldDefs, weka.core.pmml.TransformationDictionary transDict)` Static factory method that returns a subclass of Expression that encapsulates the type of expression supplied as an argument.
    `Attribute` | `getFieldDef(java.lang.String attName)` Return the named attribute from the list of reference fields.
    `int` | `getFieldDefIndex(java.lang.String attName)`
    `FieldMetaInfo.Optype` | `getOptype()` Get the optype of the result of applying this Expression.
    `abstract double` | `getResult(double[] incoming)` Get the result of evaluating the expression.
    `abstract java.lang.String` | `getResultCategorical(double[] incoming)` Gets the result of evaluating the expression when the optype is categorical or ordinal as the actual String value.
    `double` | `getResultContinuous(double[] incoming)` Get the result of evaluating the expression for continuous optype.
    `void` | `setFieldDefs(java.util.ArrayList<Attribute> fieldDefs)` Set the field definitions for this Expression to use
    `java.lang.String` | `toString()`
    `java.lang.String` | `toString(java.lang.String pad)`

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### Expression

          public Expression(FieldMetaInfo.Optype opType,
                    java.util.ArrayList<Attribute> fieldDefs)

  - ### Method Detail

    - #### setFieldDefs

          public void setFieldDefs(java.util.ArrayList<Attribute> fieldDefs)
                            throws java.lang.Exception

      Set the field definitions for this Expression to use
      Parameters:
        `fieldDefs` - the field definitions to use
      Throws:
        `java.lang.Exception` - if there is a problem setting the field definitions

    - #### getResult

          public abstract double getResult(double[] incoming)
                                    throws java.lang.Exception

      Get the result of evaluating the expression. In the case of a continuous optype, a real number is returned; in the case of a categorical/ordinal optype, the index of the nominal value is returned as a double.
      Parameters:
        `incoming` - the incoming parameter values
      Returns:
        the result of evaluating the expression
      Throws:
        `java.lang.Exception` - if there is a problem computing the result

    - #### getResultContinuous

          public double getResultContinuous(double[] incoming)
                                     throws java.lang.Exception

      Get the result of evaluating the expression for continuous optype. Is the same as calling getResult() when the optype is continuous.
      Parameters:
        `incoming` - the incoming parameter values mining schema
      Returns:
        the result of evaluating the expression.
      Throws:
        `java.lang.Exception` - if the optype is not continuous.

    - #### getResultCategorical

          public abstract java.lang.String getResultCategorical(double[] incoming)
                                                         throws java.lang.Exception

      Gets the result of evaluating the expression when the optype is categorical or ordinal as the actual String value.
      Parameters:
        `incoming` - the incoming parameter values
      Returns:
        the result of evaluating the expression
      Throws:
        `java.lang.Exception` - if the optype is continuous

    - #### getExpression

          public static Expression getExpression(org.w3c.dom.Node container,
                                 FieldMetaInfo.Optype opType,
                                 java.util.ArrayList<Attribute> fieldDefs,
                                 weka.core.pmml.TransformationDictionary transDict)
                                          throws java.lang.Exception

      Static factory method that returns a subclass of Expression that encapsulates the type of expression contained in the Element supplied. Assumes that there is just one expression contained in the supplied Element.
      Parameters:
        `container` - the Node containing the expression
        `opType` - the optype of the value returned by this Expression.
        `fieldDefs` - an ArrayList of Attributes for the fields that this Expression may need to access Since Expressions are children of either DerivedFields or DefineFuntions, they will have the same optype as their parent.
        `transDict` - the TransformationDictionary (may be null if there is no dictionary)
      Returns:
        an Expression object or null if there is no known expression in the container
      Throws:
        `java.lang.Exception` - for unsupported Expression types

    - #### getExpression

          public static Expression getExpression(java.lang.String name,
                                 org.w3c.dom.Node expression,
                                 FieldMetaInfo.Optype opType,
                                 java.util.ArrayList<Attribute> fieldDefs,
                                 weka.core.pmml.TransformationDictionary transDict)
                                          throws java.lang.Exception

      Static factory method that returns a subclass of Expression that encapsulates the type of expression supplied as an argument.
      Parameters:
        `name` - the name of the Expression to get
        `expression` - the Node containing the expression
        `opType` - the optype of the value returned by this Expression.
        `fieldDefs` - an ArrayList of Attributes for the fields that this Expression may need to access Since Expressions are children of either DerivedFields or DefineFuntions, they will have the same optype as their parent.
        `transDict` - the TransformationDictionary (may be null if there is no dictionary)
      Returns:
        an Expression object or null if there is no known expression in the container
      Throws:
        `java.lang.Exception` - for unsupported Expression types

    - #### getFieldDef

          public Attribute getFieldDef(java.lang.String attName)

      Return the named attribute from the list of reference fields.
      Parameters:
        `attName` - the name of the attribute to retrieve
      Returns:
        the named attribute (or null if it can't be found).

    - #### getFieldDefIndex

          public int getFieldDefIndex(java.lang.String attName)

    - #### getOptype

          public FieldMetaInfo.Optype getOptype()

      Get the optype of the result of applying this Expression.
      Returns:
        the optype of the result of applying this Expression

    - #### toString

          public java.lang.String toString()

      Overrides:
        `toString` in class `java.lang.Object`

    - #### toString

          public java.lang.String toString(java.lang.String pad)