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

Class LengthExpression<T,R>

java.lang.Object

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

org.apache.qpid.server.query.engine.parsing.expression.function.AbstractFunctionExpression<T,java.lang.Integer>

org.apache.qpid.server.query.engine.parsing.expression.function.string.LengthExpression<T,R>

Type Parameters:

T - Input parameter type

R - Return parameter type

All Implemented Interfaces:

java.util.function.Function<T,java.lang.Integer>, Expression<T,java.lang.Integer>, ExpressionNode<T,java.lang.Integer>

public class LengthExpression<T,R>
extends AbstractFunctionExpression<T,java.lang.Integer>

LENGTH takes a string parameter and returns its length. The implicit conversion to strings follows the existing rules for data type conversions. If any argument is NULL, LENGTH returns 0.

Field Summary

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

_functionName

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

_metadata

Constructor Summary

Constructors

Constructor	Description
LengthExpression(java.lang.String alias, java.util.List<ExpressionNode<T,?>> args)	Constructor initializes children expression list

Method Summary

Modifier and Type	Method	Description
java.lang.Integer	apply(T value)	Performs length operation using parameters and the value supplied

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

evaluateChild, getFunctionName, getOptionalConstantParameter, getOptionalParameter, getRequiredParameter

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

containsAggregation, ctx, evaluateChild, getAggregations, getAlias, 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

Constructor Detail

LengthExpression

public LengthExpression(java.lang.String alias,
                        java.util.List<ExpressionNode<T,?>> args)

Constructor initializes children expression list

Parameters:

alias - Expression alias

args - List of children expressions

Method Detail

apply

public java.lang.Integer apply(T value)

Performs length operation using parameters and the value supplied

Parameters:

value - Object to handle

Returns:

Resulting string