com.speedment.runtime.compute.trait

Interface ToNullable<T,R,NON_NULLABLE extends Expression<T>>

Type Parameters:

T - type to extract from

R - return type

NON_NULLABLE - the expression type obtained if the nullability of this expression is handled

All Superinterfaces:

Expression<T>, Function<T,R>

All Known Subinterfaces:

ToBigDecimalNullable<T>, ToBooleanNullable<T>, ToByteNullable<T>, ToCharNullable<T>, ToDoubleNullable<T>, ToEnumNullable<T,E>, ToFloatNullable<T>, ToIntNullable<T>, ToLongNullable<T>, ToShortNullable<T>, ToStringNullable<T>

public interface ToNullable<T,R,NON_NULLABLE extends Expression<T>>
extends Function<T,R>, Expression<T>

Trait for expressions that result in a nullable value. Those expressions have additional methods for checking for null-values.

Since:

3.1.0

Author:

Emil Forslund

Method Summary

Modifier and Type	Method and Description
default IsNotNull<T,R>	isNotNull() Returns a Predicate that is false for any values that would make this expression return null and true for any values that would make this expression return a result.
default boolean	isNotNull(T object) Returns false if the specified object would cause this methods Function.apply(Object)-method to return null, and otherwise true.
default IsNull<T,R>	isNull() Returns a Predicate that is true for any values that would make this expression return null and false for any values that would make this expression return a result.
default boolean	isNull(T object) Returns true if the specified object would cause this methods Function.apply(Object)-method to return null, and otherwise false.
NON_NULLABLE	orElse(R value) Returns an equivalent expression as this, except that it will return the value if given an argument that would cause this expression to return null.
NON_NULLABLE	orElseGet(NON_NULLABLE getter) Returns an equivalent expression as this, except that it will return the getter expression if given an argument that would cause this expression to return null.
NON_NULLABLE	orThrow() Returns an equivalent expression as this, except that it will throw a NullPointerException if given an argument that would cause this expression to return null.

Methods inherited from interface java.util.function.Function

andThen, apply, compose, identity

Methods inherited from interface com.speedment.runtime.compute.expression.Expression

expressionType

Method Detail

isNull

default IsNull<T,R> isNull()

Returns a Predicate that is true for any values that would make this expression return null and false for any values that would make this expression return a result.

Returns:

a predicate that tests if this expression would return null

isNotNull

default IsNotNull<T,R> isNotNull()

Returns a Predicate that is false for any values that would make this expression return null and true for any values that would make this expression return a result.

Returns:

a predicate that tests if this expression would return something other than null

isNull

default boolean isNull(T object)

Returns true if the specified object would cause this methods Function.apply(Object)-method to return null, and otherwise false.

Parameters:

object - the incoming entity to test on

Returns:

true if the expression would return null, else false

isNotNull

default boolean isNotNull(T object)

Returns false if the specified object would cause this methods Function.apply(Object)-method to return null, and otherwise true.

Parameters:

object - the incoming entity to test on

Returns:

false if the expression would return null, else true

orThrow

NON_NULLABLE orThrow()

Returns an equivalent expression as this, except that it will throw a NullPointerException if given an argument that would cause this expression to return null.

Returns:

the expression if present

orElseGet

NON_NULLABLE orElseGet(NON_NULLABLE getter)

Returns an equivalent expression as this, except that it will return the getter expression if given an argument that would cause this expression to return null.

Parameters:

getter - to apply if null

Returns:

the expression if present, otherwise return getter

orElse

NON_NULLABLE orElse(R value)

Returns an equivalent expression as this, except that it will return the value if given an argument that would cause this expression to return null.

Parameters:

value - value to use if null

Returns:

the expression if present, otherwise return value