Merge pull request #52 from kemitix/result-or-throw-wraps
[result] orElseThrow() wraps the error exception in an unchecked MonResultException
This commit is contained in:
commit
ef56892af0
8 changed files with 216 additions and 3 deletions
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@ -1,6 +1,11 @@
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CHANGELOG
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CHANGELOG
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=========
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=========
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1.1.0
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-----
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* [result] add orElseThrow(Class) and orElseThrowUnchecked()
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1.0.0
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1.0.0
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-----
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-----
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27
README.org
27
README.org
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@ -806,6 +806,7 @@
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.thenWith(v -> () -> {throw new IOException();});
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.thenWith(v -> () -> {throw new IOException();});
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#+END_SRC
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#+END_SRC
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**** =Result<Maybe<T>> maybe(Predicate<T> predicate)=
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**** =Result<Maybe<T>> maybe(Predicate<T> predicate)=
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Wraps the value within the Result in a Maybe, either a Just if the
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Wraps the value within the Result in a Maybe, either a Just if the
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@ -820,7 +821,7 @@
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**** =T orElseThrow()=
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**** =T orElseThrow()=
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Extracts the successful value from the result, or throws the error
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Extracts the successful value from the result, or throws the error
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Throwable.
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=Throwable=.
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#+BEGIN_SRC java
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#+BEGIN_SRC java
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final Integer result = Result.of(() -> getValue())
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final Integer result = Result.of(() -> getValue())
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@ -828,6 +829,29 @@
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#+END_SRC
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#+END_SRC
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**** =<E extends Exception> T orElseThrow(Class<E> type) throws E=
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Extracts the successful value from the result, or throws the error when it
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is of the given type. Any other errors will be thrown inside an
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=UnexpectedErrorResultException=.
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#+BEGIN_SRC java
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final Integer result = Result.of(() -> getValue())
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.orElseThrow(IOException.class);
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#+END_SRC
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**** =T orElseThrowUnchecked()=
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Extracts the successful value from the result, or throws the error within
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an =ErrorResultException=.
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#+BEGIN_SRC java
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final Integer result = Result.of(() -> getValue())
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.orElseThrowUnchecked();
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#+END_SRC
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**** =void onError(Consumer<Throwable> errorConsumer)=
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**** =void onError(Consumer<Throwable> errorConsumer)=
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A handler for error states.
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A handler for error states.
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@ -972,6 +996,7 @@
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final Lazy<String> stringLazy = uuidLazy.map(v -> v.toString());
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final Lazy<String> stringLazy = uuidLazy.map(v -> v.toString());
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#+END_SRC
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#+END_SRC
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** Either
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** Either
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Allows handling a value that can be one of two types, a left value/type or a
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Allows handling a value that can be one of two types, a left value/type or a
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@ -77,6 +77,20 @@ class Err<T> implements Result<T> {
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throw error;
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throw error;
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}
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}
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@Override
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@SuppressWarnings("unchecked")
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public <E extends Exception> T orElseThrow(final Class<E> type) throws E {
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if (type.isInstance(error)) {
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throw (E) error;
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}
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throw UnexpectedErrorResultException.with(error);
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}
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@Override
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public T orElseThrowUnchecked() {
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throw ErrorResultException.with(error);
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}
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@Override
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@Override
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public Result<T> peek(final Consumer<T> consumer) {
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public Result<T> peek(final Consumer<T> consumer) {
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return this;
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return this;
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@ -0,0 +1,46 @@
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/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2018 Paul Campbell
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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* and associated documentation files (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies
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* or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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* AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package net.kemitix.mon.result;
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/**
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* An unchecked wrapper fot exceptions thrown within a {@link Result}.
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*
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* <p>Used by {@link Result#orElseThrowUnchecked()} when the {@link Result} is an error.</p>
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*
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* @author Paul Campbell (pcampbell@kemitix.net)
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*/
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public final class ErrorResultException extends RuntimeException {
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private ErrorResultException(final Throwable cause) {
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super(cause);
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}
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/**
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* Creates a new object.
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*
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* @param cause the cause
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* @return a {@link ErrorResultException} containing the cause
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*/
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static ErrorResultException with(final Throwable cause) {
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return new ErrorResultException(cause);
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}
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}
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@ -99,7 +99,7 @@ public interface Result<T> extends Functor<T, Result<?>> {
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@SuppressWarnings("illegalcatch")
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@SuppressWarnings("illegalcatch")
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public static <T> Maybe<T> toMaybe(final Result<T> result) {
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public static <T> Maybe<T> toMaybe(final Result<T> result) {
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try {
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try {
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return Maybe.just(result.orElseThrow());
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return Maybe.just(result.orElseThrow(Exception.class));
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} catch (final Throwable throwable) {
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} catch (final Throwable throwable) {
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return Maybe.nothing();
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return Maybe.nothing();
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}
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}
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@ -109,11 +109,29 @@ public interface Result<T> extends Functor<T, Result<?>> {
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* Extracts the successful value from the result, or throws the error Throwable.
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* Extracts the successful value from the result, or throws the error Throwable.
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*
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*
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* @return the value if a success
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* @return the value if a success
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* @throws Throwable the result is an error
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* @throws Throwable if the result is an error
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*/
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*/
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@SuppressWarnings("illegalthrows")
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@SuppressWarnings("illegalthrows")
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public abstract T orElseThrow() throws Throwable;
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public abstract T orElseThrow() throws Throwable;
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/**
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* Extracts the successful value from the result, or throws the error Throwable.
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*
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* @param type the type of checked exception that may be thrown
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* @param <E> the type of the checked exception to throw
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*
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* @return the value if a success
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* @throws E if the result is an error
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*/
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public abstract <E extends Exception> T orElseThrow(Class<E> type) throws E;
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/**
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* Extracts the successful value from the result, or throws the error in a {@link UnexpectedErrorResultException}.
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*
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* @return the value if a success
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*/
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public abstract T orElseThrowUnchecked();
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/**
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/**
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* Swaps the inner Result of a Maybe, so that a Result is on the outside.
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* Swaps the inner Result of a Maybe, so that a Result is on the outside.
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*
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*
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@ -75,6 +75,16 @@ class Success<T> implements Result<T> {
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return value;
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return value;
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}
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}
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@Override
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public <E extends Exception> T orElseThrow(final Class<E> type) throws E {
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return value;
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}
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@Override
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public T orElseThrowUnchecked() {
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return value;
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}
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@Override
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@Override
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public Result<T> peek(final Consumer<T> consumer) {
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public Result<T> peek(final Consumer<T> consumer) {
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consumer.accept(value);
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consumer.accept(value);
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@ -0,0 +1,47 @@
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/**
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* The MIT License (MIT)
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*
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* Copyright (c) 2018 Paul Campbell
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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* and associated documentation files (the "Software"), to deal in the Software without restriction,
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* including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies
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* or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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* AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package net.kemitix.mon.result;
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/**
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* An Unchecked wrapper for unexpected exceptions thrown within a {@link Result}.
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*
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* <p>Used by {@link Result#orElseThrow(Class)} when the {@link Result} is an error of a different type to the
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* parameter.</p>
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*
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* @author Paul Campbell (pcampbell@kemitix.net)
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*/
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public final class UnexpectedErrorResultException extends RuntimeException {
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private UnexpectedErrorResultException(final Throwable cause) {
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super(cause);
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}
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/**
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* Creates a new object.
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*
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* @param cause the cause
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* @return a {@link UnexpectedErrorResultException} containing the cause
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*/
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static UnexpectedErrorResultException with(final Throwable cause) {
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return new UnexpectedErrorResultException(cause);
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}
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}
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@ -2,6 +2,8 @@ package net.kemitix.mon;
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import lombok.RequiredArgsConstructor;
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import lombok.RequiredArgsConstructor;
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import net.kemitix.mon.maybe.Maybe;
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import net.kemitix.mon.maybe.Maybe;
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import net.kemitix.mon.result.ErrorResultException;
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import net.kemitix.mon.result.UnexpectedErrorResultException;
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import net.kemitix.mon.result.Result;
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import net.kemitix.mon.result.Result;
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import org.assertj.core.api.WithAssertions;
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import org.assertj.core.api.WithAssertions;
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import org.junit.Test;
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import org.junit.Test;
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@ -295,6 +297,52 @@ public class ResultTest implements WithAssertions {
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assertThatThrownBy(() -> error.orElseThrow()).isSameAs(exception);
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assertThatThrownBy(() -> error.orElseThrow()).isSameAs(exception);
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}
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}
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@Test public void okay_whenOrElseThrowT_isValue() throws Exception {
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//given
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final Result<Integer> ok = Result.ok(1);
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//when
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final Integer value = ok.orElseThrow(Exception.class);
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//then
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assumeThat(value).isEqualTo(1);
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}
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@Test public void errorT_whenOrElseThrowT_throwsT() {
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//given
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final RuntimeException exception = new RuntimeException();
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final Result<Object> error = Result.error(exception);
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//then
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assertThatThrownBy(() -> error.orElseThrow(RuntimeException.class)).isSameAs(exception);
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}
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@Test public void errorR_whenOrElseThrowT_throwsWrappedR() {
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//given
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final IOException exception = new IOException();
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final Result<Object> error = Result.error(exception);
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//then
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assertThatThrownBy(() -> error.orElseThrow(RuntimeException.class))
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.isInstanceOf(UnexpectedErrorResultException.class)
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.hasCause(exception);
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}
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@Test public void okay_whenOrElseThrowUnchecked_isValue() {
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//given
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final Result<Integer> ok = Result.ok(1);
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//when
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final Integer value = ok.orElseThrowUnchecked();
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//then
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assumeThat(value).isEqualTo(1);
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}
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@Test public void error_whenOrElseThrowUnchecked_throwsWrapped() {
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//given
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final IOException exception = new IOException();
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final Result<Object> error = Result.error(exception);
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//then
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assertThatThrownBy(() -> error.orElseThrowUnchecked())
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.isInstanceOf(ErrorResultException.class)
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.hasCause(exception);
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}
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@Test
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@Test
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public void justOkay_whenInvert_thenOkayJust() {
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public void justOkay_whenInvert_thenOkayJust() {
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//given
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//given
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Reference in a new issue