Package org.h2.expression.aggregate

Class JavaAggregate

java.lang.Object

org.h2.expression.Expression

org.h2.expression.analysis.DataAnalysisOperation

org.h2.expression.aggregate.AbstractAggregate

org.h2.expression.aggregate.JavaAggregate

All Implemented Interfaces:

HasSQL, Typed

public class JavaAggregate
extends AbstractAggregate

This class wraps a user-defined aggregate.

Field Summary

Fields inherited from class org.h2.expression.aggregate.AbstractAggregate

args, distinct, filterCondition, type

Fields inherited from class org.h2.expression.analysis.DataAnalysisOperation

over, overOrderBySort, select, STAGE_GROUP, STAGE_RESET, STAGE_WINDOW

Fields inherited from class org.h2.expression.Expression

AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES

Fields inherited from interface org.h2.util.HasSQL

ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS

Constructor Summary

Constructors

Constructor	Description
JavaAggregate(UserAggregate userAggregate, Expression[] args, Select select, boolean distinct)

Method Summary

Modifier and Type	Method	Description
protected Object	createAggregateData()	Create aggregate data object specific to the subclass.
Value	getAggregatedValue(SessionLocal session, Object aggregateData)	Returns aggregated value.
int	getCost()	Estimate the cost to process the expression.
protected int	getNumExpressions()	Returns the number of expressions, excluding OVER clause.
StringBuilder	getUnenclosedSQL(StringBuilder builder, int sqlFlags)	Get the SQL statement of this expression.
boolean	isEverything(ExpressionVisitor visitor)	Check if this expression and all sub-expressions can fulfill a criteria.
Expression	optimize(SessionLocal session)	Try to optimize the expression.
protected void	rememberExpressions(SessionLocal session, Value[] array)	Stores current values of expressions into the specified array.
protected void	updateAggregate(SessionLocal session, Object aggregateData)	Updates an aggregate value.
protected void	updateFromExpressions(SessionLocal session, Object aggregateData, Value[] array)	Updates the provided aggregate data from the remembered expressions.
protected void	updateGroupAggregates(SessionLocal session, int stage)	Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

Methods inherited from class org.h2.expression.aggregate.AbstractAggregate

appendTailConditions, getFilterCondition, getOrderedResultLoop, getSubexpression, getSubexpressionCount, getType, isAggregate, mapColumnsAnalysis, setEvaluatable, setFilterCondition, updateAggregate

Methods inherited from class org.h2.expression.analysis.DataAnalysisOperation

createOrder, getGroupData, getOverCondition, getOverOrderBySort, getValue, getWindowData, mapColumns, setOverCondition, updateAggregate, updateOrderedAggregate

Methods inherited from class org.h2.expression.Expression

addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getTypeIfStaticallyKnown, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimizeCondition, toString, writeExpressions, writeExpressions

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.h2.util.HasSQL

getTraceSQL

Constructor Details

JavaAggregate

public JavaAggregate(UserAggregate userAggregate,
 Expression[] args,
 Select select,
 boolean distinct)

Method Details

getCost

public int getCost()

Description copied from class: Expression

Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.

Specified by:

getCost in class Expression

Returns:

the estimated cost

getUnenclosedSQL

public StringBuilder getUnenclosedSQL(StringBuilder builder,
 int sqlFlags)

Description copied from class: Expression

Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.

Specified by:

getUnenclosedSQL in class Expression

Parameters:

builder - string builder

sqlFlags - formatting flags

Returns:

the specified string builder

isEverything

public boolean isEverything(ExpressionVisitor visitor)

Description copied from class: Expression

Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.

Overrides:

isEverything in class DataAnalysisOperation

Parameters:

visitor - the visitor

Returns:

if the criteria can be fulfilled

optimize

public Expression optimize(SessionLocal session)

Description copied from class: Expression

Try to optimize the expression.

Overrides:

optimize in class AbstractAggregate

Parameters:

session - the session

Returns:

the optimized expression

getAggregatedValue

public Value getAggregatedValue(SessionLocal session,
 Object aggregateData)

Description copied from class: DataAnalysisOperation

Returns aggregated value.

Specified by:

getAggregatedValue in class DataAnalysisOperation

Parameters:

session - the session

aggregateData - the aggregate data

Returns:

aggregated value.

updateAggregate

protected void updateAggregate(SessionLocal session,
 Object aggregateData)

Description copied from class: AbstractAggregate

Updates an aggregate value.

Specified by:

updateAggregate in class AbstractAggregate

Parameters:

session - the session

aggregateData - aggregate data

updateGroupAggregates

protected void updateGroupAggregates(SessionLocal session,
 int stage)

Description copied from class: DataAnalysisOperation

Invoked when processing group stage of grouped window queries to update arguments of this aggregate.

Overrides:

updateGroupAggregates in class AbstractAggregate

Parameters:

session - the session

stage - select stage

getNumExpressions

protected int getNumExpressions()

Description copied from class: DataAnalysisOperation

Returns the number of expressions, excluding OVER clause.

Specified by:

getNumExpressions in class DataAnalysisOperation

Returns:

the number of expressions

rememberExpressions

protected void rememberExpressions(SessionLocal session,
 Value[] array)

Description copied from class: DataAnalysisOperation

Stores current values of expressions into the specified array.

Specified by:

rememberExpressions in class DataAnalysisOperation

Parameters:

session - the session

array - array to store values of expressions

updateFromExpressions

protected void updateFromExpressions(SessionLocal session,
 Object aggregateData,
 Value[] array)

Description copied from class: AbstractAggregate

Updates the provided aggregate data from the remembered expressions.

Specified by:

updateFromExpressions in class AbstractAggregate

Parameters:

session - the session

aggregateData - aggregate data

array - values of expressions

createAggregateData

protected Object createAggregateData()

Description copied from class: DataAnalysisOperation

Create aggregate data object specific to the subclass.

Specified by:

createAggregateData in class DataAnalysisOperation

Returns:

aggregate-specific data object.