public class NestedIterationExecNode extends ExecNode
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 and Description |
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NestedIterationExecNode(int[] nestedStreams)
Ctor.
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Modifier and Type | Method and Description |
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void |
addChildNode(ExecNode childNode)
Add a child node.
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void |
print(IndentWriter writer)
Output the execution strategy.
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void |
process(EventBean lookupEvent,
EventBean[] prefillPath,
java.util.Collection<EventBean[]> result,
ExprEvaluatorContext exprEvaluatorContext)
Process single event using the prefill events to compile lookup results.
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public NestedIterationExecNode(int[] nestedStreams)
nestedStreams
- - array of integers defining order of streams in nested join.public void addChildNode(ExecNode childNode)
childNode
- to addpublic void process(EventBean lookupEvent, EventBean[] prefillPath, java.util.Collection<EventBean[]> result, ExprEvaluatorContext exprEvaluatorContext)
ExecNode
process
in class ExecNode
lookupEvent
- - event to look up for or query forprefillPath
- - 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 toexprEvaluatorContext
- context for expression evaluationpublic void print(IndentWriter writer)
ExecNode