no.digipost

Class DiggBase

java.lang.Object

no.digipost.DiggBase

public final class DiggBase
extends Object

Party people, turn up tha...

–– DiggBase ––

This class contains basic utilities. Basically.

Method Summary

Modifier and Type	Method and Description
static <T,R> Stream<R>	extract(T object, Function<? super T,? extends R>... extractors) Extract (derive) multiple values from one given object.
static <T,R> Stream<R>	extractIfPresent(T object, Function<? super T,? extends Optional<R>>... extractors) Extract (derive) multiple values from one given object.
static <T> T	nonNull(String descriptiveRefKey, Function<? super String,T> refResolver) Not allow null-references.
static <T,X extends Throwable> T	nonNull(String descriptiveRefKey, Function<? super String,T> refResolver, Function<? super String,X> throwIfNull) Not allow null-references.
static <T> T	nonNull(String description, T t) Not allow null-references.
static <T,X extends Throwable> T	nonNull(String description, T t, Function<? super String,X> throwIfNull) Not allow null-references.
static <T,X extends Throwable> T	nonNull(T t, Supplier<X> throwIfNull) Not allow null-references.

Methods inherited from class java.lang.Object

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

Method Detail

nonNull

public static <T> T nonNull(String description,
                            T t)

Not allow null-references.

Parameters:

description - A small description of the reference. Will be used in the exception message if the reference is null

t - the reference

Returns:

the same instance given as argument.

Throws:

NullPointerException - if t is null.

nonNull

public static <T,X extends Throwable> T nonNull(String description,
                                                T t,
                                                Function<? super String,X> throwIfNull)
                                         throws X extends Throwable

Not allow null-references.

Parameters:

description - A small description of the reference. Will be used in the exception message if the reference is null

t - the reference

throwIfNull - Construct the exception to be thrown if the reference is null.

Returns:

the same instance given as argument.

Throws:

X - if t is null.

X extends Throwable

nonNull

public static <T,X extends Throwable> T nonNull(T t,
                                                Supplier<X> throwIfNull)
                                         throws X extends Throwable

Not allow null-references.

Parameters:

t - the reference

throwIfNull - the exception to throw if t is null

Returns:

the same instance given as argument.

Throws:

X - if t is null.

X extends Throwable

nonNull

public static <T> T nonNull(String descriptiveRefKey,
                            Function<? super String,T> refResolver)

Not allow null-references. This is a convenience method for when a descriptive refKey can be used to resolve the reference, for instance to resolve resources on classpath with .class::getResourceAsStream. The refKey will appear in the exception message if the resolved reference is null.

Parameters:

descriptiveRefKey - the key used to resolve the reference

refResolver - the function the will resolve the non-null result based on the description.

Returns:

the reference resolved by refResolver, never null

nonNull

public static <T,X extends Throwable> T nonNull(String descriptiveRefKey,
                                                Function<? super String,T> refResolver,
                                                Function<? super String,X> throwIfNull)
                                         throws X extends Throwable

Not allow null-references.

Parameters:

descriptiveRefKey - the key used to resolve the reference

refResolver - the function the will resolve the non-null result based on the description.

throwIfNull - the function to construct the exception if the refResolver yields null.

Returns:

the reference resolved by refResolver, never null

Throws:

X - if refResolver yields null

X extends Throwable

extract

@SafeVarargs
public static final <T,R> Stream<R> extract(T object,
                                                         Function<? super T,? extends R>... extractors)

Extract (derive) multiple values from one given object.

Type Parameters:

T - The type of the object to extract from.

R - The resulting most common type of the extracted values. Typically, the extractors should yield the same type.

Parameters:

object - the object to extract values from.

extractors - each function that will extract a value from the given object. The resulting value must not be null. Use extract(Object, Function...) if the extractors may yield non-existing values.

Returns:

a stream of the extracted values. The resulting stream will have the same size as the amount of given extractors.

extractIfPresent

@SafeVarargs
public static final <T,R> Stream<R> extractIfPresent(T object,
                                                                  Function<? super T,? extends Optional<R>>... extractors)

Extract (derive) multiple values from one given object. This will only include the "present" values yielded from the given extractors, and is a shorthand for:

{@link #extract(Object, Function...) extract(object, extractors...)}{@link Stream#filter(java.util.function.Predicate) .filter(}{@link Optional#isPresent() Optional::isPresent)}{@link Stream#map(Function) .map(}{@link Optional#get() Optional::get)}

Type Parameters:

T - The type of the object to extract from.

R - The resulting most common type of the extracted values. Typically, the extractors should yield the same type.

Parameters:

object - the object to extract values from.

extractors - each function that will extract a value from the given object.

Returns:

a stream of values to be extracted. The resulting stream will have either the same size as or less than the amount of given extractors.