com.holonplatform.core

Interface NullExpression<T>

Type Parameters:

T - Expression type

All Superinterfaces:

ConverterExpression<T>, Expression, TypedExpression<T>

All Known Implementing Classes:

DefaultNullExpression

public interface NullExpression<T>
extends ConverterExpression<T>

A TypedExpression which represents a null value, with expression value conversion support.

Since:

5.1.0

Nested Class Summary

Nested classes/interfaces inherited from interface com.holonplatform.core.Expression

Expression.ExpressionResolverFunction<E extends Expression,R extends Expression>, Expression.InvalidExpressionException

Method Summary

Modifier and Type	Method and Description
static <T> NullExpression<T>	create(Class<? extends T> type) Create a new NullExpression instance.
static <T> NullExpression<T>	create(TypedExpression<T> expression) Create a new NullExpression instance, using given expression to inherit an ExpressionValueConverter, if available.
Object	getModelValue() Get the model data type value, using the ExpressionValueConverter to convert constant expression value, if available.

Methods inherited from interface com.holonplatform.core.ConverterExpression

getExpressionValueConverter, getModelType, getModelValue

Methods inherited from interface com.holonplatform.core.TypedExpression

getTemporalType, getType, isCollectionExpression, isConverterExpression

Methods inherited from interface com.holonplatform.core.Expression

validate

Method Detail

getModelValue

Object getModelValue()

Get the model data type value, using the ExpressionValueConverter to convert constant expression value, if available. If an ExpressionValueConverter is not available, null is returned.

Returns:

The model-converted expression value if an ExpressionValueConverter is available, or null otherwise

create

static <T> NullExpression<T> create(Class<? extends T> type)

Create a new NullExpression instance.

Type Parameters:

T - Expression type

Parameters:

type - Expression type (not null)

Returns:

A new NullExpression

create

static <T> NullExpression<T> create(TypedExpression<T> expression)

Create a new NullExpression instance, using given expression to inherit an ExpressionValueConverter, if available.

Type Parameters:

T - Expression type

Parameters:

expression - Expression form which to inherit an ExpressionValueConverter, if available

Returns:

A new NullExpression