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

java.lang.Object
  extended by org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator
Direct Known Subclasses:
ExprNodeColumnEvaluator, ExprNodeConstantEvaluator, ExprNodeFieldEvaluator, ExprNodeGenericFuncEvaluator, ExprNodeNullEvaluator

public abstract class ExprNodeEvaluator
extends Object


Constructor Summary
ExprNodeEvaluator()
           
 
Method Summary
abstract  Object evaluate(Object row)
          Evaluate the expression given the row.
abstract  ObjectInspector initialize(ObjectInspector rowInspector)
          Initialize should be called once and only once.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExprNodeEvaluator

public ExprNodeEvaluator()
Method Detail

initialize

public abstract ObjectInspector initialize(ObjectInspector rowInspector)
                                    throws HiveException
Initialize should be called once and only once. Return the ObjectInspector for the return value, given the rowInspector.

Throws:
HiveException

evaluate

public abstract Object evaluate(Object row)
                         throws HiveException
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.

Throws:
HiveException


Copyright © 2009 The Apache Software Foundation