Class OneOfN

java.lang.Object

de.xima.fc.common.data.algebraic.OneOfN

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

OneOfN.Either, OneOfN.Just, OneOfN.None, OneOfN.OneOf3, OneOfN.OneOf4, OneOfN.OneOf5

public abstract class OneOfN
extends Object
implements Serializable

Base class for emulating algebraic sum types (also known as a discriminated union) of N elements.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	OneOfN.Either<T1,T2>	Emulates a sum type consisting of 2 cases.
static interface	OneOfN.EitherMatcher<R,T1,T2>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.
static final class	OneOfN.Just<T1>	Emulates a sum type consisting of 1 case.
static interface	OneOfN.JustMatcher<R,T1>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.
static final class	OneOfN.None	Emulates a sum type consisting of 0 cases.
static interface	OneOfN.NoneMatcher<R>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.
static final class	OneOfN.OneOf3<T1,T2,T3>	Emulates a sum type consisting of 3 cases.
static interface	OneOfN.OneOf3Matcher<R,T1,T2,T3>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.
static final class	OneOfN.OneOf4<T1,T2,T3,T4>	Emulates a sum type consisting of 4 cases.
static interface	OneOfN.OneOf4Matcher<R,T1,T2,T3,T4>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.
static final class	OneOfN.OneOf5<T1,T2,T3,T4,T5>	Emulates a sum type consisting of 5 cases.
static interface	OneOfN.OneOf5Matcher<R,T1,T2,T3,T4,T5>	A matcher object that contains a handler for each case and can be used to reduce a sum type to a single value.

Field Summary

Fields

Modifier and Type	Field	Description
protected final int	choice
protected final Object	value

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
int	getChoice()
protected final Object	getOrThrow(int choice)
Object	getValue()	Checks which case applies and returns the value for that case.
int	hashCode()
protected final boolean	is(int choice)
protected final Optional<Object>	select(int choice)
final String	toString()

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

choice

protected final int choice

value

protected final Object value

Method Details

equals

public boolean equals(Object o)

Overrides:

equals in class Object

getChoice

public int getChoice()

Returns:

The 0-based index representing the case for which a value is present.

getValue

public Object getValue()

Checks which case applies and returns the value for that case. You need to cast it yourself to the required type.

Returns:

The value of this sum type.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public final String toString()

Overrides:

toString in class Object

getOrThrow

protected final Object getOrThrow(int choice)

Parameters:

choice - Index of the case to get.

Returns:

The value of the given case, if present.

Throws:

IllegalArgumentException - If the given case is not present.

is

protected final boolean is(int choice)

Parameters:

choice - Index of the case to check.

Returns:

Whether a value is present for the given case.

select

protected final Optional<Object> select(int choice)

Parameters:

choice - Index of the case to get.

Returns:

The value of the given case, if present.