org.apache.hadoop.hive.ql.exec
Class ExprNodeGenericFuncEvaluator

java.lang.Object
  extended by org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator
      extended by org.apache.hadoop.hive.ql.exec.ExprNodeGenericFuncEvaluator

public class ExprNodeGenericFuncEvaluator
extends ExprNodeEvaluator

ExprNodeGenericFuncEvaluator.


Field Summary
protected  ExprNodeGenericFuncDesc expr
           
 
Constructor Summary
ExprNodeGenericFuncEvaluator(ExprNodeGenericFuncDesc expr)
           
 
Method Summary
 Integer compare(Object row)
          If the genericUDF is a base comparison, it returns an integer based on the result of comparing the two sides of the UDF, like the compareTo method in Comparable.
 Object evaluate(Object row)
          Evaluate the expression given the row.
 ObjectInspector initialize(ObjectInspector rowInspector)
          Initialize should be called once and only once.
 boolean isDeterministic()
          Return whether this node (and all children nodes) are deterministic.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

expr

protected ExprNodeGenericFuncDesc expr
Constructor Detail

ExprNodeGenericFuncEvaluator

public ExprNodeGenericFuncEvaluator(ExprNodeGenericFuncDesc expr)
Method Detail

initialize

public ObjectInspector initialize(ObjectInspector rowInspector)
                           throws HiveException
Description copied from class: ExprNodeEvaluator
Initialize should be called once and only once. Return the ObjectInspector for the return value, given the rowInspector.

Specified by:
initialize in class ExprNodeEvaluator
Throws:
HiveException

isDeterministic

public boolean isDeterministic()
Description copied from class: ExprNodeEvaluator
Return whether this node (and all children nodes) are deterministic.

Overrides:
isDeterministic in class ExprNodeEvaluator

evaluate

public Object evaluate(Object row)
                throws HiveException
Description copied from class: ExprNodeEvaluator
Evaluate the expression given the row. This method should use the rowInspector passed in from initialize to inspect the row object. The return value will be inspected by the return value of initialize.

Specified by:
evaluate in class ExprNodeEvaluator
Throws:
HiveException

compare

public Integer compare(Object row)
                throws HiveException
If the genericUDF is a base comparison, it returns an integer based on the result of comparing the two sides of the UDF, like the compareTo method in Comparable. If the genericUDF is not a base comparison, or there is an error executing the comparison, it returns null.

Parameters:
row -
Returns:
Throws:
HiveException


Copyright © 2011 The Apache Software Foundation