org.diirt.datasource.formula

Class AbstractVNumberVNumberToVNumberFormulaFunction

java.lang.Object

org.diirt.datasource.formula.AbstractVNumberVNumberToVNumberFormulaFunction

All Implemented Interfaces:

FormulaFunction

public abstract class AbstractVNumberVNumberToVNumberFormulaFunction
extends Object
implements FormulaFunction

Abstract class for formula functions that take two VNumbers as arguments and return a VNumber.

This class takes care of:

• extracting double value from VNumber
• null handling - returns null if one argument is null
• alarm handling - returns highest alarm
• time handling - returns latest time, or now if no time is available
• display handling - returns display none

Author:

carcassi

Constructor Summary

Constructors

Constructor and Description
AbstractVNumberVNumberToVNumberFormulaFunction(String name, String description, String arg1Name, String arg2Name) Creates a new function.

Method Summary

Modifier and Type	Method and Description
abstract double	calculate(double arg1, double arg2) Calculates the result based on the two arguments.
Object	calculate(List<Object> args) Calculate the result of the function given the arguments.
List<String>	getArgumentNames() The ordered list of the argument names.
List<Class<?>>	getArgumentTypes() The ordered list of the arguments type.
String	getDescription() Return the description of the function.
String	getName() Return the name of the function.
Class<?>	getReturnType() The type of the function result.
boolean	isPure() Whether the function is a pure function, given the same arguments always returns the same result.
boolean	isVarArgs() Whether the function takes a variable number of arguments.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractVNumberVNumberToVNumberFormulaFunction

public AbstractVNumberVNumberToVNumberFormulaFunction(String name,
                                                      String description,
                                                      String arg1Name,
                                                      String arg2Name)

Creates a new function.

Parameters:

name - function name; can't be null

description - function description; can't be null

arg1Name - first argument name; can't be null

arg2Name - second argument name; can't be null

Method Detail

getName

public final String getName()

Description copied from interface: FormulaFunction

Return the name of the function.

Specified by:

getName in interface FormulaFunction

Returns:

the function name

getDescription

public final String getDescription()

Description copied from interface: FormulaFunction

Return the description of the function.

Specified by:

getDescription in interface FormulaFunction

Returns:

the function description

isPure

public final boolean isPure()

Description copied from interface: FormulaFunction

Whether the function is a pure function, given the same arguments always returns the same result.

Specified by:

isPure in interface FormulaFunction

Returns:

true if it's a pure function

isVarArgs

public final boolean isVarArgs()

Description copied from interface: FormulaFunction

Whether the function takes a variable number of arguments.

Variable arguments can only be at the end of the argument list, and have the same type.

Specified by:

isVarArgs in interface FormulaFunction

Returns:

true if the function can accept a variable number of arguments

getArgumentTypes

public final List<Class<?>> getArgumentTypes()

Description copied from interface: FormulaFunction

The ordered list of the arguments type.

Specified by:

getArgumentTypes in interface FormulaFunction

Returns:

the types of the arguments

getArgumentNames

public final List<String> getArgumentNames()

Description copied from interface: FormulaFunction

The ordered list of the argument names.

Specified by:

getArgumentNames in interface FormulaFunction

Returns:

the names of the names

getReturnType

public final Class<?> getReturnType()

Description copied from interface: FormulaFunction

The type of the function result.

Specified by:

getReturnType in interface FormulaFunction

Returns:

the result type

calculate

public final Object calculate(List<Object> args)

Description copied from interface: FormulaFunction

Calculate the result of the function given the arguments.

Specified by:

calculate in interface FormulaFunction

Parameters:

args - the argument list

Returns:

the result of the function

calculate

public abstract double calculate(double arg1,
                                 double arg2)

Calculates the result based on the two arguments. This is the only method one has to implement.

Parameters:

arg1 - the first argument

arg2 - the second argument

Returns:

the result