Package com.espertech.esper.common.internal.epl.join.exec.base

Class NestedIterationExecNode

java.lang.Object

com.espertech.esper.common.internal.epl.join.strategy.ExecNode

com.espertech.esper.common.internal.epl.join.exec.base.NestedIterationExecNode

public class NestedIterationExecNode
extends ExecNode

Execution node that performs a nested iteration over all child nodes.

Each child node under this node typically represents a table lookup. The implementation 'hops' from the first child to the next recursively for each row returned by a child.

It passes a 'prototype' row (prefillPath) to each new child which contains the current partial event set.

Constructor Summary

Constructors

Constructor	Description
NestedIterationExecNode(int[] nestedStreams)	Ctor.

Method Summary

Modifier and Type	Method	Description
void	addChildNode(ExecNode childNode)	Add a child node.
void	print(IndentWriter writer)	Output the execution strategy.
void	process(EventBean lookupEvent, EventBean[] prefillPath, Collection<EventBean[]> result, ExprEvaluatorContext exprEvaluatorContext)	Process single event using the prefill events to compile lookup results.
protected void	recursiveNestedJoin(EventBean lookupEvent, int nestingOrderIndex, EventBean[] currentPath, Collection<EventBean[]> result, ExprEvaluatorContext exprEvaluatorContext)	Recursive method to run through all child nodes and, for each result set tuple returned by a child node, execute the inner child of the child node until there are no inner child nodes.

Methods inherited from class com.espertech.esper.common.internal.epl.join.strategy.ExecNode

print

Methods inherited from class java.lang.Object

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

Constructor Details

NestedIterationExecNode

public NestedIterationExecNode(int[] nestedStreams)

Ctor.

Parameters:

nestedStreams - - array of integers defining order of streams in nested join.

Method Details

addChildNode

public void addChildNode(ExecNode childNode)

Add a child node.

Parameters:

childNode - to add

process

public void process(EventBean lookupEvent,
 EventBean[] prefillPath,
 Collection<EventBean[]> result,
 ExprEvaluatorContext exprEvaluatorContext)

Description copied from class: ExecNode

Process single event using the prefill events to compile lookup results.

Specified by:

process in class ExecNode

Parameters:

lookupEvent - - event to look up for or query for

prefillPath - - set of events currently in the example tuple to serve as a prototype for result rows.

result - is the list of tuples to add a result row to

exprEvaluatorContext - context for expression evaluation

recursiveNestedJoin

protected void recursiveNestedJoin(EventBean lookupEvent,
 int nestingOrderIndex,
 EventBean[] currentPath,
 Collection<EventBean[]> result,
 ExprEvaluatorContext exprEvaluatorContext)

Recursive method to run through all child nodes and, for each result set tuple returned by a child node, execute the inner child of the child node until there are no inner child nodes.

Parameters:

lookupEvent - - current event to use for lookup by child node

nestingOrderIndex - - index within the child nodes indicating what nesting level we are at

currentPath - - prototype result row to use by child nodes for generating result rows

result - - result tuple rows to be populated

exprEvaluatorContext - context for expression evalauation

print

public void print(IndentWriter writer)

Description copied from class: ExecNode

Output the execution strategy.

Specified by:

print in class ExecNode

Parameters:

writer - to output to