Package com.singularsys.jep.misc.nullwrapper.functions

Class NullWrappedLazyLogical

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.misc.nullwrapper.functions.NullWrappedLazyLogical

All Implemented Interfaces:

CallbackEvaluationI, NullWrappedFunctionI, PostfixMathCommandI, java.io.Serializable

public class NullWrappedLazyLogical
extends PostfixMathCommand
implements CallbackEvaluationI, NullWrappedFunctionI

Null wrapped versions of the LazyLogical functions. In version 3.5 the convention has been changed to behave like the MySQL logical operators.

OR truth table

A OR B	True	False	null
True	True	True	True
False	True	False	null
null	True	null	null

AND truth table

A AND B	True	False	null
True	True	False	null
False	False	False	False
null	null	False	null

NOT truth table

A	NOT A
True	False
False	True
null	null

Since:

3.4

Version:

3.5

Author:

Richard Morris

See Also:

LazyLogical, Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	allowNumbers
static int	AND
protected int	id	Represents which logical operator this is.
static int	OR

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
NullWrappedLazyLogical(int id_in)	Standard constructor, non zero Numbers will be treated as true and zero Numbers as false.
NullWrappedLazyLogical(int id_in, boolean disallowNumbers)	Constructor which restricts type of arguments.

Method Summary

Modifier and Type	Method	Description
java.lang.Object	evaluate(Node node, Evaluator pv)	Performs some special evaluation on the node.
PostfixMathCommandI	getRoot()	Get to function which this function wraps.

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, checkNumberOfParameters, getName, getNumberOfParameters, run, setCurNumberOfParameters, setName, toString, toString

Methods inherited from class java.lang.Object

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

Field Detail

AND

public static final int AND

See Also:

Constant Field Values

OR

public static final int OR

See Also:

Constant Field Values

id

protected int id

Represents which logical operator this is.

allowNumbers

protected boolean allowNumbers

Constructor Detail

NullWrappedLazyLogical

public NullWrappedLazyLogical(int id_in)

Standard constructor, non zero Numbers will be treated as true and zero Numbers as false.

Parameters:

id_in - either of the constants AND or OR

NullWrappedLazyLogical

public NullWrappedLazyLogical(int id_in,
                              boolean disallowNumbers)

Constructor which restricts type of arguments.

Parameters:

id_in -

disallowNumbers - if true Number arguments will raise exceptions, otherwise as the Standard constructor.

Method Detail

getRoot

public PostfixMathCommandI getRoot()

Description copied from interface: NullWrappedFunctionI

Get to function which this function wraps.

Specified by:

getRoot in interface NullWrappedFunctionI

Returns:

the root function, may be "this".

evaluate

public java.lang.Object evaluate(Node node,
                                 Evaluator pv)
                          throws EvaluationException

Description copied from interface: CallbackEvaluationI

Performs some special evaluation on the node. This method has the responsibility for evaluating the children of the node and it should generally call

 pv.eval(node.jjtGetChild(i))   
 

for each child. The SymbolTable is not passed as an argument. This is because it is better practice to get and set variable values by using node.getVar().setValue() rather that through the SymbolTable with requires a hashtable lookup.

Specified by:

evaluate in interface CallbackEvaluationI

Parameters:

node - The current node

pv - The visitor, can be used evaluate the children

Returns:

the value after evaluation. This value will be passed to other functions higher up the node tree. The value can be any type including Double or Vector<Object>

Throws:

EvaluationException - if the calculation cannot be performed

See Also:

Evaluator