Package org.apache.qpid.server.query.engine.parsing.query

Class SelectExpression<T,R>

java.lang.Object

org.apache.qpid.server.query.engine.parsing.expression.AbstractExpressionNode<T,R>

org.apache.qpid.server.query.engine.parsing.expression.set.AbstractSetExpression<T,R>

org.apache.qpid.server.query.engine.parsing.query.SelectExpression<T,R>

Type Parameters:

T - Input parameter type

R - Return parameter type

All Implemented Interfaces:

Function<T,R>, Expression<T,R>, ExpressionNode<T,R>, SetExpression<T,R>

public class SelectExpression<T,R>
extends AbstractSetExpression<T,R>

Contains information about a select expression, which may contain SELECT clause, FROM clause, WHERE clause, GROUP BY clause and HAVING clause.

Field Summary

Fields inherited from class org.apache.qpid.server.query.engine.parsing.expression.set.AbstractSetExpression

_distinct

Fields inherited from class org.apache.qpid.server.query.engine.parsing.expression.AbstractExpressionNode

_metadata

Constructor Summary

Constructors

Constructor	Description
SelectExpression()	Default constructor sets default distinct property value (false)
SelectExpression(boolean distinct)	Constructor sets distinct property value

Method Summary

Modifier and Type	Method	Description
R	apply(T value)	Evaluates select expression and returns evaluation result
void	distinct(boolean distinct)
void	from(String domain, String alias)
List<ProjectionExpression<T,R>>	getAggregationItems()
String	getAlias()	Returns expression alias
FromExpression<T,Stream<?>,ConfiguredObject<?>>	getFrom()
List<ProjectionExpression<T,R>>	getGroupBy()
HavingExpression<T,R>	getHaving()
int	getOrdinal()
List<ProjectionExpression<T,R>>	getProjections()	Returns list of projections
Predicate<T>	getWhere()
void	groupBy(ProjectionExpression<T,R> expression)
boolean	hasAggregationItems()
void	having(ExpressionNode<T,R> predicate)
boolean	isDistinct()
boolean	isSelectAll()
void	join()
void	resetOrdinal()
void	selectAll()
void	selectItem(ProjectionExpression<T,R> expression)
String	toString()
void	where(ExpressionNode<T,R> predicate)

Methods inherited from class org.apache.qpid.server.query.engine.parsing.expression.set.AbstractSetExpression

getSelections

Methods inherited from class org.apache.qpid.server.query.engine.parsing.expression.AbstractExpressionNode

containsAggregation, ctx, evaluateChild, getAggregations, getChild, getChildren, getParent, isAccessor, isInstantlyEvaluable, setAlias, setParent

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.qpid.server.query.engine.parsing.expression.Expression

andThen

Methods inherited from interface org.apache.qpid.server.query.engine.parsing.expression.ExpressionNode

containsAggregation, getAggregations, getChildren, getParent, isAccessor, isInstantlyEvaluable, setAlias, setParent

Methods inherited from interface java.util.function.Function

andThen, compose

Constructor Detail

SelectExpression

public SelectExpression()

Default constructor sets default distinct property value (false)

SelectExpression

public SelectExpression(boolean distinct)

Constructor sets distinct property value

Parameters:

distinct - Distinct flag

Method Detail

apply

public R apply(T value)

Evaluates select expression and returns evaluation result

Parameters:

value - Object to handle (is ignored)

Returns:

Evaluation result

getProjections

public List<ProjectionExpression<T,R>> getProjections()

Description copied from class: AbstractSetExpression

Returns list of projections

Specified by:

getProjections in interface SetExpression<T,R>

Overrides:

getProjections in class AbstractSetExpression<T,R>

Returns:

List of projections

isDistinct

public boolean isDistinct()

isSelectAll

public boolean isSelectAll()

getOrdinal

public int getOrdinal()

getFrom

public FromExpression<T,Stream<?>,ConfiguredObject<?>> getFrom()

getWhere

public Predicate<T> getWhere()

getGroupBy

public List<ProjectionExpression<T,R>> getGroupBy()

getHaving

public HavingExpression<T,R> getHaving()

selectAll

public void selectAll()

selectItem

public void selectItem(ProjectionExpression<T,R> expression)

distinct

public void distinct(boolean distinct)

from

public void from(String domain,
                 String alias)

join

public void join()

where

public void where(ExpressionNode<T,R> predicate)

having

public void having(ExpressionNode<T,R> predicate)

groupBy

public void groupBy(ProjectionExpression<T,R> expression)

resetOrdinal

public void resetOrdinal()

hasAggregationItems

public boolean hasAggregationItems()

getAggregationItems

public List<ProjectionExpression<T,R>> getAggregationItems()

getAlias

public String getAlias()

Description copied from class: AbstractExpressionNode

Returns expression alias

Specified by:

getAlias in interface ExpressionNode<T,R>

Overrides:

getAlias in class AbstractExpressionNode<T,R>

Returns:

Expression alias

toString

public String toString()

Overrides:

toString in class AbstractExpressionNode<T,R>