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

Class ConstantExpression<T,R>

java.lang.Object

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

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

Type Parameters:

T - Input parameter type

R - Output parameter type

All Implemented Interfaces:

java.util.function.Function<T,R>, java.util.function.Supplier<R>, Expression<T,R>, ExpressionNode<T,R>

Direct Known Subclasses:

FalseLiteralExpression, FromExpression, NullLiteralExpression, NumberLiteralExpression, StringLiteralExpression, TrueLiteralExpression

public class ConstantExpression<T,R>
extends AbstractExpressionNode<T,R>
implements java.util.function.Supplier<R>

Holds a constant value.

Field Summary

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

_metadata

Constructor Summary

Constructors

Constructor	Description
ConstantExpression(java.lang.String alias, R value)	Constructor stores alias and value
ConstantExpression(R value)	Constructor stores value

Method Summary

Modifier and Type	Method	Description
R	apply(T ignore)
R	get()
java.lang.String	getAlias()	Alias getter
static <T,R> ConstantExpression<T,R>	of(java.lang.String alias, R value)	Shorthand creation method
static <T,R> ConstantExpression<T,R>	of(R value)	Shorthand creation method
java.lang.String	toString()

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 java.util.function.Function

andThen, compose

Constructor Detail

ConstantExpression

public ConstantExpression(R value)

Constructor stores value

Parameters:

value - Constant value

ConstantExpression

public ConstantExpression(java.lang.String alias,
                          R value)

Constructor stores alias and value

Parameters:

alias - Expression alias

value - Constant value

Method Detail

of

public static <T,R> ConstantExpression<T,R> of(R value)

Shorthand creation method

Type Parameters:

T - Input parameter type

R - Output parameter type

Parameters:

value - Constant value

Returns:

ConstantExpression instance

of

public static <T,R> ConstantExpression<T,R> of(java.lang.String alias,
                                                           R value)

Shorthand creation method

Type Parameters:

T - Input parameter type

R - Output parameter type

Parameters:

alias - Expression alias

value - Constant value

Returns:

ConstantExpression instance

apply

public R apply(T ignore)

Specified by:

apply in interface Expression<T,R>

Specified by:

apply in interface java.util.function.Function<T,R>

get

public R get()

Specified by:

get in interface java.util.function.Supplier<T>

getAlias

public java.lang.String getAlias()

Alias getter

Specified by:

getAlias in interface ExpressionNode<T,R>

Overrides:

getAlias in class AbstractExpressionNode<T,R>

Returns:

Expression alias

toString

public java.lang.String toString()

Overrides:

toString in class AbstractExpressionNode<T,R>