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

Class SubstringExpression<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.String>

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

Type Parameters:

T - Input parameter type

R - Return parameter type

All Implemented Interfaces:

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

public class SubstringExpression<T,R>
extends AbstractFunctionExpression<T,java.lang.String>

SUBSTRING takes a source parameter, a start index parameter and optional length parameter. Returns substring of a source string from the start index to the end or using the length parameter. If source string is NULL, return NULL. If start index is negative, function extracts from the end of the string.

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

Method Summary

Modifier and Type	Method	Description
java.lang.String	apply(T value)	Performs substring 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

SubstringExpression

public SubstringExpression(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.String apply(T value)

Performs substring operation using parameters and the value supplied

Parameters:

value - Object to handle

Returns:

Resulting string