Package org.apache.commons.lang3.function

Interface FailableFunction<T,R,E extends Throwable>

Type Parameters:

T - Input type 1.

R - Return type.

E - The kind of thrown exception or error.

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface FailableFunction<T,R,E extends Throwable>

A functional interface like Function that declares a Throwable.

Since:

3.11

Field Summary

Fields

Modifier and Type	Field	Description
static final FailableFunction	NOP	NOP singleton

Method Summary

Modifier and Type	Method	Description
default <V> FailableFunction<T,V,E>	andThen(FailableFunction<? super R,? extends V,E> after)	Returns a composed FailableFunction like Function.andThen(Function).
R	apply(T input)	Applies this function.
default <V> FailableFunction<V,R,E>	compose(FailableFunction<? super V,? extends T,E> before)	Returns a composed FailableFunction like Function.compose(Function).
static <T, R, E extends Throwable> FailableFunction<T,R,E>	function(FailableFunction<T,R,E> function)	Starts a fluent chain like function(foo::bar).andThen(...).andThen(...).apply(...);
static <T, E extends Throwable> FailableFunction<T,T,E>	identity()	Returns a function that always returns its input argument.
static <T, R, E extends Throwable> FailableFunction<T,R,E>	nop()	Returns The NOP singleton.

Field Details

NOP

static final FailableFunction NOP

NOP singleton

Method Details

function

static <T,
R,
E extends Throwable>
FailableFunction<T,R,E> function(FailableFunction<T,R,E> function)

Starts a fluent chain like function(foo::bar).andThen(...).andThen(...).apply(...);

Type Parameters:

T - Input type.

R - Return type.

E - The kind of thrown exception or error.

Parameters:

function - the argument to return.

Returns:

the argument

Since:

3.14.0

identity

static <T,
E extends Throwable>
FailableFunction<T,T,E> identity()

Returns a function that always returns its input argument.

Type Parameters:

T - the type of the input and output objects to the function

E - The kind of thrown exception or error.

Returns:

a function that always returns its input argument

nop

static <T,
R,
E extends Throwable>
FailableFunction<T,R,E> nop()

Returns The NOP singleton.

Type Parameters:

T - Consumed type.

R - Return type.

E - The kind of thrown exception or error.

Returns:

The NOP singleton.

andThen

default <V> FailableFunction<T,V,E> andThen(FailableFunction<? super R,? extends V,E> after)

Returns a composed FailableFunction like Function.andThen(Function).

Type Parameters:

V - the output type of the after function, and of the composed function.

Parameters:

after - the operation to perform after this one.

Returns:

a composed FailableFunction like Function.andThen(Function).

Throws:

NullPointerException - when after is null.

apply

R apply(T input)
 throws E

Applies this function.

Parameters:

input - the input for the function

Returns:

the result of the function

Throws:

E - Thrown when the function fails.

compose

default <V> FailableFunction<V,R,E> compose(FailableFunction<? super V,? extends T,E> before)

Returns a composed FailableFunction like Function.compose(Function).

Type Parameters:

V - the input type to the before function, and to the composed function.

Parameters:

before - the operator to apply before this one.

Returns:

a composed FailableFunction like Function.compose(Function).

Throws:

NullPointerException - if before is null.

See Also:

• andThen(FailableFunction)