Package com.yahoo.search.grouping.request

Class AggregatorNode

java.lang.Object

com.yahoo.search.grouping.request.GroupingNode

com.yahoo.search.grouping.request.GroupingExpression

com.yahoo.search.grouping.request.AggregatorNode

Direct Known Subclasses:

AvgAggregator, CountAggregator, MaxAggregator, MinAggregator, StandardDeviationAggregator, SumAggregator, XorAggregator

public abstract class AggregatorNode
extends GroupingExpression

This class represents an aggregated value in a GroupingExpression. Because it operates on a list of data, it can not be used as a document-level expression (i.e. level 0, see GroupingExpression.resolveLevel(int)). The contained expression is evaluated at the level of the aggregator minus 1.

Author:

Simon Thoresen Hult

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AggregatorNode(String image, String label, Integer level)
protected	AggregatorNode(String image, String label, Integer level, GroupingExpression exp)

Method Summary

Modifier and Type	Method	Description
GroupingExpression	getExpression()	Returns the expression that this node aggregates on.
void	resolveLevel(int level)	Resolves the conceptual level of this expression.
void	visit(ExpressionVisitor visitor)	Recursively calls ExpressionVisitor.visitExpression(GroupingExpression) for this expression and all of its argument expressions.

Methods inherited from class com.yahoo.search.grouping.request.GroupingExpression

asImage, asString, copy, getLevel, getLevelOrNull, setLabel

Methods inherited from class com.yahoo.search.grouping.request.GroupingNode

getImage, getLabel, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregatorNode

protected AggregatorNode(String image,
                         String label,
                         Integer level)

AggregatorNode

protected AggregatorNode(String image,
                         String label,
                         Integer level,
                         GroupingExpression exp)

Method Detail

getExpression

public GroupingExpression getExpression()

Returns the expression that this node aggregates on.

Returns:

The expression.

resolveLevel

public void resolveLevel(int level)

Description copied from class: GroupingExpression

Resolves the conceptual level of this expression. This level represents the type of data that is consumed by this expression, where level 0 is a single hit, level 1 is a group, level 2 is a list of groups, and so forth. This method verifies the input level against the expression type, and recursively resolves the level of all argument expressions.

Overrides:

resolveLevel in class GroupingExpression

Parameters:

level - The level of the input data.

visit

public void visit(ExpressionVisitor visitor)

Description copied from class: GroupingExpression

Recursively calls ExpressionVisitor.visitExpression(GroupingExpression) for this expression and all of its argument expressions.

Overrides:

visit in class GroupingExpression

Parameters:

visitor - The visitor to call.