Package com.willhains.purity

Class Single<Raw,This extends Single<Raw,This>>

java.lang.Object

com.willhains.purity.Single<Raw,This>

Type Parameters:

Raw - The underlying type.

This - Self-reference to the subclass type itself.

public abstract class Single<Raw,This extends Single<Raw,This>>
extends Object

A value type wrapping an underlying data type. This supertype and its abstract subtypes make it easy to implement Pure value types.

Author:

willhains

Field Summary

Fields

Modifier and Type	Field	Description
protected Raw	raw	The raw underlying value.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Single(Raw rawValue, Function<? super Raw,? extends This> constructor)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object other)
static boolean	equals(Object object1, Object object2)	Compare two objects for equality.
boolean	equals(This that)
Optional<This>	filter(Predicate<? super Raw> condition)	Test the raw value by condition.
This	flatMap(Function<? super Raw,? extends This> mapper)	Construct a new value of this type with the raw underlying value converted by mapper.
int	hashCode()
static int	hashCode(Object object)	Generate a hash code for object.
boolean	is(Predicate<? super Raw> condition)	Test the raw value with condition.
boolean	isNot(Predicate<? super Raw> condition)	Reverse of is(Predicate).
This	map(Function<? super Raw,? extends Raw> mapper)	Construct a new value of this type with the raw underlying value converted by mapper.
Raw	raw()	Return the raw underlying value.
String	toString()
static String	toString(Object object)	Format a string to represent object.

Methods inherited from class java.lang.Object

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

Field Detail

raw

protected final Raw raw

The raw underlying value. Do not mutate!

Constructor Detail

Single

protected Single(Raw rawValue,
                 Function<? super Raw,? extends This> constructor)

Parameters:

rawValue - The raw value this object will represent.

constructor - A method reference to the constructor of the implementing subclass.

Method Detail

raw

public Raw raw()

Return the raw underlying value.

Implementation Requirements:

Override this method if Single is mutable. The default implementation assumes raw is immutable, and returns it as-is. The returned Single value, if mutable, could be mutated, so the overriding method should be careful to make a deep, defensive copy to return to the caller.

hashCode

public final int hashCode()

Overrides:

hashCode in class Object

hashCode

public static int hashCode(Object object)

Generate a hash code for object. If object is an array, combine the hashes of each element.

equals

public final boolean equals(Object other)

Overrides:

equals in class Object

equals

public final boolean equals(This that)

equals

public static boolean equals(Object object1,
                             Object object2)

Compare two objects for equality. If they are arrays, compare their elements.

toString

public String toString()

Overrides:

toString in class Object

toString

public static String toString(Object object)

Format a string to represent object. If object is an array, include each element.

is

public final boolean is(Predicate<? super Raw> condition)

Test the raw value with condition. This method is useful when using Optional.filter(java.util.function.Predicate<? super T>) or Stream.filter(java.util.function.Predicate<? super T>).

 optional.filter(x -> x.is(String::isEmpty))
 

Parameters:

condition - a Predicate that tests the raw value type.

Returns:

true if the underlying raw value satisfies condition; false otherwise.

isNot

public final boolean isNot(Predicate<? super Raw> condition)

Reverse of is(Predicate).

filter

public final Optional<This> filter(Predicate<? super Raw> condition)

Test the raw value by condition.

Returns:

an Optional containing this instance if the condition is met; empty otherwise.

See Also:

is(Predicate)

map

public final This map(Function<? super Raw,? extends Raw> mapper)

Construct a new value of this type with the raw underlying value converted by mapper.

Parameters:

mapper - The mapping function to apply to the raw underlying value.

Returns:

A new instance of this type.

flatMap

public final This flatMap(Function<? super Raw,? extends This> mapper)

Construct a new value of this type with the raw underlying value converted by mapper.

Parameters:

mapper - The mapping function to apply to the raw underlying value.

Returns:

The value returned by mapper.