org.apache.hadoop.hive.ql.exec
Class ExprNodeEvaluator<T extends ExprNodeDesc>

java.lang.Object
  org.apache.hadoop.hive.ql.exec.ExprNodeEvaluator<T>

Direct Known Subclasses:

ExprNodeColumnEvaluator, ExprNodeConstantEvaluator, ExprNodeEvaluatorHead, ExprNodeEvaluatorRef, ExprNodeFieldEvaluator, ExprNodeGenericFuncEvaluator, ExprNodeNullEvaluator

public abstract class ExprNodeEvaluator<T extends ExprNodeDesc>
extends Object

ExprNodeEvaluator.

Field Summary

protected T	expr
protected ObjectInspector	outputOI

Constructor Summary

ExprNodeEvaluator(T expr)

Method Summary

protected abstract Object	_evaluate(Object row, int version) Evaluate value
Object	evaluate(Object row)
protected Object	evaluate(Object row, int version) Evaluate the expression given the row.
ExprNodeEvaluator[]	getChildren() Return child evaluators if exist
T	getExpr() Return child evaluators if exist
ObjectInspector	getOutputOI() Return initialized ObjectInspector.
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.
boolean	isStateful() Return whether this node (or any children nodes) are stateful.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

expr

protected final T extends ExprNodeDesc expr

outputOI

protected ObjectInspector outputOI

Constructor Detail

ExprNodeEvaluator

public ExprNodeEvaluator(T expr)

Method Detail

getExpr

public T getExpr()

Return child evaluators if exist

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

getOutputOI

public ObjectInspector getOutputOI()

Return initialized ObjectInspector. If it's not initilized, throws runtime exception

evaluate

public Object evaluate(Object row)
                throws HiveException

Throws:

HiveException

evaluate

protected Object evaluate(Object row,
                          int version)
                   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. If this evaluator is referenced by others, store it for them

Throws:

HiveException

_evaluate

protected abstract Object _evaluate(Object row,
                                    int version)
                             throws HiveException

Evaluate value

Throws:

HiveException

isDeterministic

public boolean isDeterministic()

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

isStateful

public boolean isStateful()

Return whether this node (or any children nodes) are stateful.

getChildren

public ExprNodeEvaluator[] getChildren()

Return child evaluators if exist