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

java.lang.Object
  org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator

Direct Known Subclasses:

ExprNodeColumnEvaluator, ExprNodeConstantEvaluator, ExprNodeFieldEvaluator, ExprNodeGenericFuncEvaluator, ExprNodeNullEvaluator

public abstract class ExprNodeEvaluator
extends Object

ExprNodeEvaluator.

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.
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

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

isDeterministic

public boolean isDeterministic()

Return whether this node (and all children nodes) are deterministic.