org.apache.hadoop.hive.ql.lib

Class DefaultRuleDispatcher

java.lang.Object

org.apache.hadoop.hive.ql.lib.DefaultRuleDispatcher

All Implemented Interfaces:

Dispatcher, SemanticDispatcher

public class DefaultRuleDispatcher
extends Object
implements SemanticDispatcher

Dispatches calls to relevant method in processor. The user registers various rules with the dispatcher, and the processor corresponding to closest matching rule is fired.

Constructor Summary

Constructors

Constructor and Description
DefaultRuleDispatcher(SemanticNodeProcessor defaultProc, Map<SemanticRule,SemanticNodeProcessor> rules, NodeProcessorCtx procCtx) Constructor.

Method Summary

Modifier and Type	Method and Description
Object	dispatch(Node nd, Stack<Node> ndStack, Object... nodeOutputs) Dispatcher function.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultRuleDispatcher

public DefaultRuleDispatcher(SemanticNodeProcessor defaultProc,
                             Map<SemanticRule,SemanticNodeProcessor> rules,
                             NodeProcessorCtx procCtx)

Constructor.

Parameters:

defaultProc - default processor to be fired if no rule matches

rules - operator processor that handles actual processing of the node

procCtx - operator processor context, which is opaque to the dispatcher

Method Detail

dispatch

public Object dispatch(Node nd,
                       Stack<Node> ndStack,
                       Object... nodeOutputs)
                throws SemanticException

Dispatcher function.

Specified by:

dispatch in interface Dispatcher

Specified by:

dispatch in interface SemanticDispatcher

Parameters:

nd - operator to process

ndStack - the operators encountered so far

nodeOutputs - The argument list of outputs from processing other nodes that are passed to this dispatcher from the walker.

Returns:

Object The return object from the processing call.

Throws:

SemanticException