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

java.lang.Object
  org.apache.hadoop.hive.ql.lib.DefaultRuleDispatcher

All Implemented Interfaces:

Dispatcher

public class DefaultRuleDispatcher
extends Object
implements Dispatcher

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

DefaultRuleDispatcher(NodeProcessor defaultProc, Map<Rule,NodeProcessor> rules, NodeProcessorCtx procCtx)
Constructor.

Method Summary

Object

dispatch(Node nd, Stack<Node> ndStack, Object... nodeOutputs) Dispatcher function.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultRuleDispatcher

public DefaultRuleDispatcher(NodeProcessor defaultProc,
                             Map<Rule,NodeProcessor> 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

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