Package com.im.df.api.dml

Class Operators.NullOperator

java.lang.Object

com.im.df.api.dml.DFOperator

com.im.df.api.dml.Operators.SimpleFieldValuesOperator

com.im.df.api.dml.Operators.NullOperator

Enclosing class:

Operators

public static class Operators.NullOperator
extends Operators.SimpleFieldValuesOperator

IS NULL/ IS NOT NULL operators.

Constructor Summary

Constructors

Constructor	Description
NullOperator(java.lang.String persistName, java.lang.String displayName)

Method Summary

Modifier and Type	Method	Description
boolean	isFieldAcceptableAsOperand(DFField field)	This is just an utility method which must be implemented by subclasses.

Methods inherited from class com.im.df.api.dml.Operators.SimpleFieldValuesOperator

getValidFormatMsg, isEmptyStringAllowed, parseOperands, validate

Methods inherited from class com.im.df.api.dml.DFOperator

correctNumberOfOperands, getDisplayName, getDisplayNameInExpression, getMaxOperands, getMinOperands, getPersistName, getStartingWith, getStartingWithOperator, getToStringPart, toString, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

NullOperator

public NullOperator(java.lang.String persistName,
                    java.lang.String displayName)

Method Detail

isFieldAcceptableAsOperand

public boolean isFieldAcceptableAsOperand(DFField field)

Description copied from class: DFOperator

This is just an utility method which must be implemented by subclasses. It tests if the given field is acceptable as operand for this DFOperator. It can return true even for fields which are recognized as invalid later. This is just rough test in the beginning of validation to filter inappropriate fields.

For example some operator takes two operands of different types (text, integer,...), but both must be of the same type. In this case this method returns true for all text, integer etc. fields, but if you use combination of [text, integer] as operands, it will be invalid.

Overrides:

isFieldAcceptableAsOperand in class Operators.SimpleFieldValuesOperator

Parameters:

field - The field to be tested

Returns:

True if field seems to be acceptable, false otherwise.