org.opendaylight.yangtools.concepts

Class CheckedValue<T,E extends Exception>

java.lang.Object

org.opendaylight.yangtools.concepts.Variant<T,E>

org.opendaylight.yangtools.concepts.CheckedValue<T,E>

Type Parameters:

T - Value type

E - Exception type

@Beta
 @NonNullByDefault
 @ThreadSafe
public class CheckedValue<T,E extends Exception>
extends Variant<T,E>

Utility holder similar to Optional, except the empty case contains an Exception, which should be reported, for example via throwing it. It provides analogous methods such as isPresent(), ifPresent(Consumer), get(), orElse(Object), orElseGet(Supplier), orElseThrow(Function).

Author:

Robert Varga

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CheckedValue(E violation, @Nullable Void dummy)
protected	CheckedValue(T value)

Method Summary

Modifier and Type	Method and Description
boolean	completeFuture(CompletableFuture<T> future) Complete target CompletableFuture either successfully or exceptionally based on the state of this object.
boolean	completeFuture(com.google.common.util.concurrent.SettableFuture<T> future) Complete target SettableFuture either successfully or exceptionally based on the state of this object.
<U> CheckedValue<U,E>	flatMap(Function<? super T,CheckedValue<U,E>> mapper)
T	get() Return the contained value if isPresent() would return true, throws IllegalStateException otherwise.
E	getException() Return the contained error string if isPresent() would return false, throws IllegalStateException otherwise.
void	ifPresent(Consumer<? super T> consumer) If a value is present, invoke the specified consumer with the value, otherwise do nothing.
boolean	isPresent() Return true if a value is present.
<U> CheckedValue<U,E>	map(Function<? super T,U> mapper)
<X extends Exception> CheckedValue<T,X>	mapException(Function<? super E,X> mapper)
static <T,E extends Exception> CheckedValue<T,E>	ofException(E cause) Create a new instance containing an Exception.
static <T,E extends Exception> CheckedValue<T,E>	ofValue(T value) Create a new instance containing specified value.
static <T,U,E extends Exception> CheckedValue<T,E>	ofVariant(Variant<T,U> variant, Function<U,E> mapper) Convert a Variant into a CheckedValue, converting the second value into an exception.
T	orElse(T other) Return contained value if present, otherwise return supplied value.
T	orElseGet(Supplier<T> supplier) Return contained value if present, otherwise return the value produced by a supplier.
T	orElseThrow() Return contained value if present or throw the exception alternative.
<X extends Throwable> T	orElseThrow(Function<E,X> exceptionMapper) Return contained value if present or throw the exception alternative mapped through provided mapper.
<X extends Throwable> T	orElseThrow(Supplier<X> supplier) Return contained value if present or throw the exception supplied by supplier.
CompletableFuture<T>	toCompletableFuture() Transform this object into an immediately-completed CompletableFuture.
com.google.common.util.concurrent.FluentFuture<T>	toFluentFuture() Transform this object into an immediately-completed FluentFuture.

Methods inherited from class org.opendaylight.yangtools.concepts.Variant

addToString, equals, first, getFirst, getSecond, hashCode, isFirst, isSecond, ofFirst, ofSecond, second, toString, tryFirst, trySecond

Methods inherited from class java.lang.Object

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

Constructor Detail

CheckedValue

protected CheckedValue(T value)

CheckedValue

protected CheckedValue(E violation,
                       @Nullable Void dummy)

Method Detail

ofException

public static <T,E extends Exception> CheckedValue<T,E> ofException(E cause)

Create a new instance containing an Exception.

Type Parameters:

T - Value type

E - Exception type

Parameters:

cause - Throwable

Returns:

A new instance

Throws:

NullPointerException - if cause is null

ofValue

public static <T,E extends Exception> CheckedValue<T,E> ofValue(T value)

Create a new instance containing specified value.

Type Parameters:

T - Value type

E - Exception type

Parameters:

value - Value

Returns:

A new instance

Throws:

NullPointerException - if value is null

ofVariant

public static <T,U,E extends Exception> CheckedValue<T,E> ofVariant(Variant<T,U> variant,
                                                                    Function<U,E> mapper)

Convert a Variant into a CheckedValue, converting the second value into an exception.

Type Parameters:

T - First alternative type

U - Second alternative type

E - Exception type

Parameters:

variant - Input variant

mapper - Mapping function from second alternative to an exception

Returns:

Resulting CheckedValue

get

public final T get()

Return the contained value if isPresent() would return true, throws IllegalStateException otherwise.

Returns:

Contained value

Throws:

IllegalStateException - if an error string is present.

getException

public final E getException()

Return the contained error string if isPresent() would return false, throws IllegalStateException otherwise.

Returns:

Throwable which was used to instantiate this object, or absent if it was instantiated using an error string.

Throws:

IllegalStateException - if a value is present.

isPresent

public final boolean isPresent()

Return true if a value is present.

Returns:

True if a value is present.

ifPresent

public final void ifPresent(Consumer<? super T> consumer)

If a value is present, invoke the specified consumer with the value, otherwise do nothing.

Parameters:

consumer - block to be executed if a value is present

Throws:

NullPointerException - if value is present and consumer is null

map

public <U> CheckedValue<U,E> map(Function<? super T,U> mapper)

mapException

public <X extends Exception> CheckedValue<T,X> mapException(Function<? super E,X> mapper)

flatMap

public <U> CheckedValue<U,E> flatMap(Function<? super T,CheckedValue<U,E>> mapper)

orElse

public final T orElse(T other)

Return contained value if present, otherwise return supplied value.

Parameters:

other - Replacement value

Returns:

Contained value or {code other}

orElseGet

public final T orElseGet(Supplier<T> supplier)

Return contained value if present, otherwise return the value produced by a supplier.

Parameters:

supplier - Replacement value supplier

Returns:

Contained value or supplier's value

Throws:

NullPointerException - if supplier is null

orElseThrow

public final T orElseThrow()
                    throws E extends Exception

Return contained value if present or throw the exception alternative.

Returns:

Contained value

Throws:

E - When there is no contained value

E extends Exception

orElseThrow

public final <X extends Throwable> T orElseThrow(Function<E,X> exceptionMapper)
                                          throws X extends Throwable

Return contained value if present or throw the exception alternative mapped through provided mapper.

Type Parameters:

X - Thrown exception type

Parameters:

exceptionMapper - Exception mapper

Returns:

Contained value

Throws:

NullPointerException - if exceptionMapper is null

X - When there is no contained value

X extends Throwable

orElseThrow

public final <X extends Throwable> T orElseThrow(Supplier<X> supplier)
                                          throws X extends Throwable

Return contained value if present or throw the exception supplied by supplier.

Type Parameters:

X - Thrown exception type

Parameters:

supplier - Exception supplier

Returns:

Contained value

Throws:

NullPointerException - if exceptionMapper is null

X - When there is no contained value

X extends Throwable

completeFuture

public final boolean completeFuture(CompletableFuture<T> future)

Complete target CompletableFuture either successfully or exceptionally based on the state of this object.

Parameters:

future - Future to complete

Returns:

True if this call has transitioned the future to a completed state, false otherwise.

Throws:

NullPointerException - if {code future} is null

completeFuture

public final boolean completeFuture(com.google.common.util.concurrent.SettableFuture<T> future)

Complete target SettableFuture either successfully or exceptionally based on the state of this object.

Parameters:

future - Future to complete

Returns:

True if this call has transitioned the future to a completed state, false otherwise.

Throws:

NullPointerException - if {code future} is null

toCompletableFuture

public final CompletableFuture<T> toCompletableFuture()

Transform this object into an immediately-completed CompletableFuture. The future will be successful if this object has a contained value or unsuccessful if this objects contains an exception.

Returns:

A CompletableFuture.

toFluentFuture

public final com.google.common.util.concurrent.FluentFuture<T> toFluentFuture()

Transform this object into an immediately-completed FluentFuture. The future will be successful if this object has a contained value or unsuccessful if this objects contains an exception.

Returns:

A FluentFuture.