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

Class IsNullExpression<T>

java.lang.Object

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

org.apache.qpid.server.query.engine.parsing.expression.comparison.AbstractComparisonExpression<T,Boolean>

org.apache.qpid.server.query.engine.parsing.expression.comparison.IsNullExpression<T>

Type Parameters:

T - Input parameter type

All Implemented Interfaces:

Function<T,Boolean>, Predicate<T>, Expression<T,Boolean>, ExpressionNode<T,Boolean>

public class IsNullExpression<T>
extends AbstractComparisonExpression<T,Boolean>

Comparison IS NULL operation. Evaluates left expression NULL value.

Field Summary

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

_operator

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

_metadata

Constructor Summary

Constructors

Constructor	Description
IsNullExpression(ExpressionNode<T,?> left)	Constructor initializes children expression list

Method Summary

Modifier and Type	Method	Description
Boolean	apply(T value)	Performs IS NULL comparison using parameters and the value supplied
String	getAlias()	Returns expression alias

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

test

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

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

Methods inherited from interface java.util.function.Function

andThen, compose

Methods inherited from interface java.util.function.Predicate

and, negate, or

Constructor Detail

IsNullExpression

public IsNullExpression(ExpressionNode<T,?> left)

Constructor initializes children expression list

Parameters:

left - Left child expression

Method Detail

apply

public Boolean apply(T value)

Performs IS NULL comparison using parameters and the value supplied

Parameters:

value - Object to handle

Returns:

Boolean result of value evaluation

getAlias

public String getAlias()

Returns expression alias

Specified by:

getAlias in interface ExpressionNode<T,Boolean>

Overrides:

getAlias in class AbstractComparisonExpression<T,Boolean>

Returns:

Expression alias