org.apache.metamodel.query

Class MapValueFunction

java.lang.Object

org.apache.metamodel.query.DefaultScalarFunction

org.apache.metamodel.query.MapValueFunction

All Implemented Interfaces:

Serializable, FunctionType, ScalarFunction

public final class MapValueFunction
extends DefaultScalarFunction

Represents a function that retrieves a value from within a column of type ColumnType.MAP or similar.

See Also:

Serialized Form

Field Summary

Fields inherited from interface org.apache.metamodel.query.FunctionType

AVG, COUNT, FIRST, JAVA_SUBSTRING, LAST, MAP_VALUE, MAX, MIN, RANDOM, SUBSTRING, SUM, TO_BOOLEAN, TO_DATE, TO_NUMBER, TO_STRING

Constructor Summary

Constructors

Constructor and Description
MapValueFunction()

Method Summary

Modifier and Type	Method and Description
Object	evaluate(Row row, Object[] parameters, SelectItem operandItem) Applies and evaluates the function on a particular row of data.
ColumnType	getExpectedColumnType(ColumnType type)
String	getFunctionName()

Methods inherited from class org.apache.metamodel.query.DefaultScalarFunction

toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MapValueFunction

public MapValueFunction()

Method Detail

evaluate

public Object evaluate(Row row,
                       Object[] parameters,
                       SelectItem operandItem)

Description copied from interface: ScalarFunction

Applies and evaluates the function on a particular row of data.

Parameters:

row - the row containing data

parameters - any parameters associated with the function call

operandItem - the select item which is the argument to this function. If a function takes multiple select items, this will be the primary one.

Returns:

getExpectedColumnType

public ColumnType getExpectedColumnType(ColumnType type)

getFunctionName

public String getFunctionName()