Package com.thanlinardos.spring_enterprise_library.objects.utils

Class FunctionUtils

java.lang.Object

com.thanlinardos.spring_enterprise_library.objects.utils.FunctionUtils

public class FunctionUtils
extends Object

Very useful utility methods for working with Functions.

Constructor Summary

Constructors

Constructor	Description
FunctionUtils()

Method Summary

Modifier and Type	Method	Description
static <T, O, R> Function<T,R>	apply(BiFunction<T,O,R> function, O object)	Method that can be used to apply with a single method argument to a bi-function.
static <T, O, S> Consumer<T>	chainAllFromOther(Collection<O> others, Function<O,S> func, BiConsumer<S,T> consumer)	Creates a null-safe consumer that applies a function to a set of another objects, then a consumer to the result.
static <T, O, S> Consumer<T>	chainAllFromSelf(Collection<O> others, Function<T,S> func, BiConsumer<S,O> consumer)	Creates a null-safe consumer that applies a function to the element, then a consumer to input object.
static <T, O, S> Consumer<T>	chainFromOther(O other, Function<O,S> func, BiConsumer<S,T> consumer)	Creates a null-safe consumer that applies a function to another object, then a consumer to the result.
static <T, O, S> Consumer<T>	chainFromSelf(O other, Function<T,S> func, BiConsumer<S,O> consumer)	Creates a null-safe consumer that applies a function to the element, then a consumer to input object.
static <T1, T2, R> Function<T1,R>	compose(Function<T1,T2> func1, Function<T2,R> func2)	Method that chains two methods and return the combined result.
static <T1, T2, R> Function<T1,Set<R>>	composeAllNullSafe(Function<T1,Set<T2>> firstGetter, Function<T2,Set<R>> finalGetter)	Method that chains two methods in a null safe wrapper and return the combined result.
static <T1, T2, R> Function<T1,R>	composeNullSafe(Function<T1,T2> firstGetter, Function<T2,R> finalGetter)	Method that chains two methods in a null safe wrapper and return the combined result.
static <T1, T2, T3, R> Function<T1,R>	composeNullSafe(Function<T1,T2> firstGetter, Function<T2,T3> secondGetter, Function<T3,R> finalGetter)	Method that chains three methods in a null safe wrapper and return the combined result.
static <T1, T2, R> Function<T1,Set<R>>	composeWithSetNullSafe(Function<T1,Set<T2>> firstGetter, Function<T2,R> finalGetter)	Method that chains two methods in a null safe wrapper and return the combined result.
static ErrorCode	getCoreExceptionErrorCodeOrUnexpectedSystemError(Exception e)	Gets the ErrorCode f it is a CoreException otherwise ErrorCode.UNEXPECTED_ERROR.
static <T> Function<T,Boolean>	negateBoolean(Function<T,Boolean> func)	Negates the result of input function.
static <U extends BasicIdJpa, R> R	rethrowWithEntityId(U entity, Function<U,R> function)	Helper method to provide ids of entity input parameters in the resulting exception if the given function throws an exception
static <T, R> Function<T,Stream<R>>	stream(Function<T,Collection<R>> function)	Returns a Function that applies the Collection.stream() method on the result of the input Function.
static <T, R> Function<T,Stream<R>>	streamOptional(Function<T,Optional<R>> function)	Returns a Function that applies the Optional.stream() method on the result of the input Function.

Methods inherited from class java.lang.Object

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

Constructor Details

FunctionUtils

public FunctionUtils()

Method Details

negateBoolean

public static <T> Function<T,Boolean> negateBoolean(Function<T,Boolean> func)

Negates the result of input function.

Type Parameters:

T - type of the input element.

Parameters:

func - the function to negate.

Returns:

the negated Function.

apply

public static <T,
O,
R> Function<T,R> apply(BiFunction<T,O,R> function,
 O object)

Method that can be used to apply with a single method argument to a bi-function.

Type Parameters:

T - type of the starting element

O - type of the object to be applied

R - type of result

Parameters:

function - the function to call with the input

object - the input

Returns:

a function that can be used to apply the input to the bi-function

compose

public static <T1,
T2,
R> Function<T1,R> compose(Function<T1,T2> func1,
 Function<T2,R> func2)

Method that chains two methods and return the combined result.

Type Parameters:

T1 - type of the first method

T2 - type of the final method

R - type the final method returns

Parameters:

func1 - the first function of the chain

func2 - the final function of the chain

Returns:

the method returns the result of the final function

composeNullSafe

public static <T1,
T2,
R> Function<T1,R> composeNullSafe(Function<T1,T2> firstGetter,
 Function<T2,R> finalGetter)

Method that chains two methods in a null safe wrapper and return the combined result.

Type Parameters:

T1 - type of the first method

T2 - type of the final method

R - type the final method returns

Parameters:

firstGetter - the first function of the chain

finalGetter - the final function of the chain

Returns:

the method returns the result of the final function

composeWithSetNullSafe

public static <T1,
T2,
R> Function<T1,Set<R>> composeWithSetNullSafe(Function<T1,Set<T2>> firstGetter,
 Function<T2,R> finalGetter)

Method that chains two methods in a null safe wrapper and return the combined result.

Type Parameters:

T1 - type set of the first method

T2 - type of the final method

R - type the final method returns

Parameters:

firstGetter - the first function of the chain

finalGetter - the final function of the chain

Returns:

the method returns the result of the final function

composeAllNullSafe

public static <T1,
T2,
R> Function<T1,Set<R>> composeAllNullSafe(Function<T1,Set<T2>> firstGetter,
 Function<T2,Set<R>> finalGetter)

Method that chains two methods in a null safe wrapper and return the combined result.

Type Parameters:

T1 - type set of the first method

T2 - type set of the final method

R - type the final method returns

Parameters:

firstGetter - the first function of the chain

finalGetter - the final function of the chain

Returns:

the method returns the result of the final function

composeNullSafe

public static <T1,
T2,
T3,
R> Function<T1,R> composeNullSafe(Function<T1,T2> firstGetter,
 Function<T2,T3> secondGetter,
 Function<T3,R> finalGetter)

Method that chains three methods in a null safe wrapper and return the combined result.

Type Parameters:

T1 - type of the first method

T2 - type of the second method

T3 - type of the final method

R - type the final method returns

Parameters:

firstGetter - the first function of the chain

secondGetter - the second function of the chain

finalGetter - the final function of the chain

Returns:

the method returns the result of the final function

chainFromOther

public static <T,
O,
S> Consumer<T> chainFromOther(@Nullable
 O other,
 Function<O,S> func,
 BiConsumer<S,T> consumer)

Creates a null-safe consumer that applies a function to another object, then a consumer to the result. This is useful, e.g., when needing to consume elements of a (possible composed) getter.

Type Parameters:

T - type of the consumed element

O - type of the "starting" object

S - type of intermediate element used by consumer

Parameters:

other - object to start chain from

func - function to apply to other

consumer - bi-consumer that takes the result of func and the applied element

Returns:

single-element consumer for an object of type T

chainAllFromOther

public static <T,
O,
S> Consumer<T> chainAllFromOther(@Nullable
 Collection<O> others,
 Function<O,S> func,
 BiConsumer<S,T> consumer)

Creates a null-safe consumer that applies a function to a set of another objects, then a consumer to the result. This is useful, e.g., when needing to consume elements of a (possible composed) getter.

Type Parameters:

T - type of the consumed element

O - type of the "starting" object

S - type of intermediate element used by consumer

Parameters:

others - objects to start chain from

func - function to apply to other

consumer - bi-consumer that takes the result of func and the applied element

Returns:

single-element consumer for an object of type T

chainFromSelf

public static <T,
O,
S> Consumer<T> chainFromSelf(@Nullable
 O other,
 Function<T,S> func,
 BiConsumer<S,O> consumer)

Creates a null-safe consumer that applies a function to the element, then a consumer to input object. This is useful, e.g., when needing to consume elements of a (possible composed) getter.

Type Parameters:

T - type of the consumed element

O - type of the other object

S - type of intermediate element used by consumer

Parameters:

other - object to consume in the end

func - function to apply to the element

consumer - bi-consumer that takes the result of func and other

Returns:

single-element consumer for an object of type T

chainAllFromSelf

public static <T,
O,
S> Consumer<T> chainAllFromSelf(@Nullable
 Collection<O> others,
 Function<T,S> func,
 BiConsumer<S,O> consumer)

Creates a null-safe consumer that applies a function to the element, then a consumer to input object. This is useful, e.g., when needing to consume elements of a (possible composed) getter.

Type Parameters:

T - type of the consumed element

O - type of the other object

S - type of intermediate element used by consumer

Parameters:

others - objects to consume in the end

func - function to apply to the element

consumer - bi-consumer that takes the result of func and an other

Returns:

single-element consumer for an object of type T

stream

public static <T,
R> Function<T,Stream<R>> stream(Function<T,Collection<R>> function)

Returns a Function that applies the Collection.stream() method on the result of the input Function. This can be used to shorten stream chains that first does a map and then a flatMap with Collection.stream().

Type Parameters:

T - type of the input element

R - type of the elements in the collection returned by the input Function

Parameters:

function - the input Function

Returns:

a Function that applies the Collection.stream() method on the result of the input Function

streamOptional

public static <T,
R> Function<T,Stream<R>> streamOptional(Function<T,Optional<R>> function)

Returns a Function that applies the Optional.stream() method on the result of the input Function. This can be used to shorten stream chains that first does a map and then a flatMap with Optional.stream().

Type Parameters:

T - type of the input element

R - type of the element in the optional returned by the input Function

Parameters:

function - the input Function

Returns:

a Function that applies the Optional.stream() method on the result of the input Function

rethrowWithEntityId

public static <U extends BasicIdJpa,
R> R rethrowWithEntityId(U entity,
 Function<U,R> function)

Helper method to provide ids of entity input parameters in the resulting exception if the given function throws an exception

Type Parameters:

U - class of the given entity

R - class of returned by function

Parameters:

entity - a given entity extending BasicIdJpa

function - a function taking the given entity

Returns:

the result of applying the function to the given entity, rethrowing any exception with an exception mentioning the entity id

getCoreExceptionErrorCodeOrUnexpectedSystemError

public static ErrorCode getCoreExceptionErrorCodeOrUnexpectedSystemError(Exception e)

Gets the ErrorCode f it is a CoreException otherwise ErrorCode.UNEXPECTED_ERROR.

Parameters:

e - a given exception

Returns:

the ErrorCode f it is a CoreException otherwise ErrorCode.UNEXPECTED_ERROR.