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

Class AbstractExpressionNode<T,R>

java.lang.Object

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

Type Parameters:

T - Input parameter type

R - Return parameter type

All Implemented Interfaces:

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

Direct Known Subclasses:

AbstractArithmeticExpression, AbstractComparisonExpression, AbstractFunctionExpression, AbstractSetExpression, AndExpression, CaseExpression, ChainedObjectAccessor, CollectionObjectAccessor, ConfiguredObjectAccessorExpression, ConstantExpression, DelegatingCollectionAccessorExpression, DelegatingObjectAccessor, ExpressionWrapperExpression, HavingExpression, MapObjectAccessor, NotExpression, ObjectAccessorExpression, OrExpression, PredicateWrapperExpression, ProjectionExpression, QueryExpression

public abstract class AbstractExpressionNode<T,R>
extends Object
implements ExpressionNode<T,R>

Abstract expression node containing base functionality

Field Summary

Fields

Modifier and Type	Field	Description
protected Metadata<T>	_metadata	Expression metadata

Constructor Summary

Constructors

Constructor	Description
AbstractExpressionNode()	Default constructor creates an empty children list and checks current query depth against the settings
AbstractExpressionNode(String alias)	Constructor stores expression alias
AbstractExpressionNode(String alias, List<ExpressionNode<T,?>> children)	Constructor stores alias and children expressions supplied
AbstractExpressionNode(String alias, ExpressionNode<T,?> first)	Constructor stores alias and child expression supplied
AbstractExpressionNode(String alias, ExpressionNode<T,?> first, ExpressionNode<T,?> second)	Constructor stores alias and children expressions supplied
AbstractExpressionNode(List<ExpressionNode<T,?>> children)	Constructor stores the supplied child expressions
AbstractExpressionNode(ExpressionNode<T,?> first)	Constructor stores child expression supplied
AbstractExpressionNode(ExpressionNode<T,?> first, ExpressionNode<T,?> second)	Constructor stores the supplied child expressions
AbstractExpressionNode(ExpressionNode<T,?> first, ExpressionNode<T,?> second, ExpressionNode<T,?> third)	Constructor stores the supplied child expressions

Method Summary

Modifier and Type	Method	Description
boolean	containsAggregation()	Determines whether expression contains aggregation nodes or not
protected EvaluationContext	ctx()	Returns current evaluation context
protected <X,Y> Y	evaluateChild(int index, X value)	Retrieves child expression by index and evaluates it against the value provided
<Y> List<AbstractAggregationExpression<T,Y>>	getAggregations()	Returns expression children being aggregation nodes
String	getAlias()	Returns expression alias
protected <X,Y> ExpressionNode<X,Y>	getChild(int index)	Retrieves child expression by index
<Y> List<ExpressionNode<T,Y>>	getChildren()	Return expression children
<Y> ExpressionNode<T,Y>	getParent()	Returns expression parent
boolean	isAccessor()	Determines whether expression is an accessor or not
boolean	isInstantlyEvaluable()	Determines whether expression can be evaluated instantly or not
void	setAlias(String alias)	Setter for alias
void	setParent(ExpressionNode<T,?> parent)	Setter for expression parent
String	toString()

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, apply

Methods inherited from interface java.util.function.Function

andThen, compose

Field Detail

_metadata

protected final Metadata<T> _metadata

Expression metadata

Constructor Detail

AbstractExpressionNode

public AbstractExpressionNode()

Default constructor creates an empty children list and checks current query depth against the settings

AbstractExpressionNode

public AbstractExpressionNode(String alias)

Constructor stores expression alias

Parameters:

alias - Expression alias

AbstractExpressionNode

public AbstractExpressionNode(ExpressionNode<T,?> first)

Constructor stores child expression supplied

Parameters:

first - Fist child

AbstractExpressionNode

public AbstractExpressionNode(String alias,
                              ExpressionNode<T,?> first)

Constructor stores alias and child expression supplied

Parameters:

alias - Expression alias

first - Fist child

AbstractExpressionNode

public AbstractExpressionNode(ExpressionNode<T,?> first,
                              ExpressionNode<T,?> second)

Constructor stores the supplied child expressions

Parameters:

first - Fist child

second - Second child

AbstractExpressionNode

public AbstractExpressionNode(String alias,
                              ExpressionNode<T,?> first,
                              ExpressionNode<T,?> second)

Constructor stores alias and children expressions supplied

Parameters:

alias - Expression alias

first - Fist child

second - Second child

AbstractExpressionNode

public AbstractExpressionNode(ExpressionNode<T,?> first,
                              ExpressionNode<T,?> second,
                              ExpressionNode<T,?> third)

Constructor stores the supplied child expressions

Parameters:

first - Fist child

second - Second child

third - Third child

AbstractExpressionNode

public AbstractExpressionNode(List<ExpressionNode<T,?>> children)

Constructor stores the supplied child expressions

Parameters:

children - List of child expressions

AbstractExpressionNode

public AbstractExpressionNode(String alias,
                              List<ExpressionNode<T,?>> children)

Constructor stores alias and children expressions supplied

Parameters:

alias - Expression alias

children - List of child expressions

Method Detail

ctx

protected final EvaluationContext ctx()

Returns current evaluation context

Returns:

Evaluation context

getParent

public <Y> ExpressionNode<T,Y> getParent()

Returns expression parent

Specified by:

getParent in interface ExpressionNode<T,R>

Returns:

Expression parent

setParent

public void setParent(ExpressionNode<T,?> parent)

Setter for expression parent

Specified by:

setParent in interface ExpressionNode<T,R>

Parameters:

parent - Expression parent

getChild

protected <X,Y> ExpressionNode<X,Y> getChild(int index)

Retrieves child expression by index

Type Parameters:

X - Child input type

Y - Child return type

Parameters:

index - Child index

Returns:

Expression child or null

evaluateChild

protected <X,Y> Y evaluateChild(int index,
                                      X value)

Retrieves child expression by index and evaluates it against the value provided

Type Parameters:

X - Child input type

Y - Child return type

Parameters:

index - Child expression index

value - Object to handle

Returns:

Evaluation result

getChildren

public <Y> List<ExpressionNode<T,Y>> getChildren()

Return expression children

Specified by:

getChildren in interface ExpressionNode<T,R>

Returns:

List of child expressions

containsAggregation

public boolean containsAggregation()

Determines whether expression contains aggregation nodes or not

Specified by:

containsAggregation in interface ExpressionNode<T,R>

Returns:

True or false

isAccessor

public boolean isAccessor()

Determines whether expression is an accessor or not

Specified by:

isAccessor in interface ExpressionNode<T,R>

Returns:

True or false

isInstantlyEvaluable

public boolean isInstantlyEvaluable()

Determines whether expression can be evaluated instantly or not

Specified by:

isInstantlyEvaluable in interface ExpressionNode<T,R>

Returns:

True or false

getAlias

public String getAlias()

Returns expression alias

Specified by:

getAlias in interface ExpressionNode<T,R>

Returns:

Expression alias

setAlias

public void setAlias(String alias)

Setter for alias

Specified by:

setAlias in interface ExpressionNode<T,R>

Parameters:

alias - Expression alias

getAggregations

public <Y> List<AbstractAggregationExpression<T,Y>> getAggregations()

Returns expression children being aggregation nodes

Specified by:

getAggregations in interface ExpressionNode<T,R>

Type Parameters:

Y - Return type

Returns:

List of aggregation expressions

toString

public String toString()

Overrides:

toString in class Object