FunctionalCheckedExceptionWrappers.java
- /*
- * *************************************************************************************************************************************************************
- *
- * TheseFoolishThings: Miscellaneous utilities
- * http://tidalwave.it/projects/thesefoolishthings
- *
- * Copyright (C) 2009 - 2025 by Tidalwave s.a.s. (http://tidalwave.it)
- *
- * *************************************************************************************************************************************************************
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
- * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
- *
- * *************************************************************************************************************************************************************
- *
- * git clone https://bitbucket.org/tidalwave/thesefoolishthings-src
- * git clone https://github.com/tidalwave-it/thesefoolishthings-src
- *
- * *************************************************************************************************************************************************************
- */
- package it.tidalwave.util;
- import jakarta.annotation.Nonnull;
- import java.util.function.Consumer;
- import java.util.function.Function;
- import java.util.function.Predicate;
- import java.util.function.Supplier;
- import java.io.IOException;
- import java.io.UncheckedIOException;
- import lombok.NoArgsConstructor;
- import static lombok.AccessLevel.PRIVATE;
- /***************************************************************************************************************************************************************
- *
- * A collections of utility methods for simplifying the syntax of lambda expressions with APIs that don't accept
- * checked exceptions (such as {@link java.util.stream.Stream}): they provide wrapped functions that have no checked
- * exception in the signature and whose implementation delegates to the original function wrapping an eventual checked
- * exception into a {@link RuntimeException}. For instance, given the following method that could not be used as a
- * {@link java.util.stream.Stream#filter(Predicate)} argument:
- *
- * <pre>
- * private boolean matchEven (final int number)
- * throws Exception
- * {
- * if (number == 13)
- * {
- * throw new Exception("13!");
- * }
- *
- * return number % 2 == 0;
- * }
- * </pre>
- *
- * working code can be written as:
- *
- * <pre>
- * try
- * {
- * List<Integer> numbers = IntStream.rangeClosed(1, 20)
- * .mapToObj(Integer::valueOf)
- * .filter(_p(this::matchEven)) // note the wrapper here
- * .collect(Collectors.toList());
- * ...
- * }
- * catch (RuntimeException e)
- * {
- * ...
- * }
- * </pre>
- *
- * Any checked exception is wrapped by a {@code RuntimeException}, but {@link IOException} is wrapped by a
- * {@link UncheckedIOException}.
- *
- * @author Fabrizio Giudici
- * @it.tidalwave.javadoc.draft
- * @since 3.2-ALPHA-1
- *
- **************************************************************************************************************************************************************/
- @NoArgsConstructor(access = PRIVATE)
- public final class FunctionalCheckedExceptionWrappers
- {
- /***********************************************************************************************************************************************************
- * A variant of {@link Function} that might throw an {@link Exception}. This interface must not be directly used,
- * it's defined to let the compiler infer functional equivalence.
- *
- * @param <T> the type of the function argument
- * @param <R> the type of the function return value
- * @hidden
- **********************************************************************************************************************************************************/
- @FunctionalInterface
- public static interface FunctionWithException<T, R>
- {
- public R apply (T t)
- throws Throwable;
- }
- /***********************************************************************************************************************************************************
- * A variant of {@link Consumer} that might throw an {@link Exception}. This interface must not be directly used,
- * it's defined to let the compiler infer functional equivalence.
- *
- * @param <T> the type of the {@code Consumer} argument
- * @hidden
- **********************************************************************************************************************************************************/
- @FunctionalInterface
- public static interface ConsumerWithException<T>
- {
- public void accept (T t)
- throws Throwable;
- }
- /***********************************************************************************************************************************************************
- * A variant of {@link Supplier} that might throw an {@link Exception}. This interface must not be directly used,
- * it's defined to let the compiler infer functional equivalence.
- *
- * @param <T> the type of the {@code Supplier} argument
- * @hidden
- **********************************************************************************************************************************************************/
- @FunctionalInterface
- public static interface SupplierWithException<T>
- {
- public T get ()
- throws Throwable;
- }
- /***********************************************************************************************************************************************************
- * A variant of {@link Predicate} that might throw an {@link Exception}. This interface must not be directly used,
- * it's defined to let the compiler infer functional equivalence.
- *
- * @param <T> the type of the {@code Predicate} argument
- * @hidden
- **********************************************************************************************************************************************************/
- @FunctionalInterface
- public static interface PredicateWithException<T>
- {
- public boolean test (T t)
- throws Throwable;
- }
- /***********************************************************************************************************************************************************
- * A variant of {@link Runnable} that might throw an {@link Exception}. This interface must not be directly used,
- * it's defined to let the compiler infer functional equivalence.
- *
- * @hidden
- **********************************************************************************************************************************************************/
- @FunctionalInterface
- public static interface RunnableWithException
- {
- @SuppressWarnings("RedundantThrows")
- public void run()
- throws Exception;
- }
- /***********************************************************************************************************************************************************
- * A wrapper for a {@link Function} that catches exceptions and wraps them into {@link RuntimeException}s.
- *
- * @param function the {@code Function} to wrap.
- * @param <T> the type of the function argument
- * @param <R> the type of the function return value
- * @return the wrapped {@code Function}
- **********************************************************************************************************************************************************/
- @Nonnull
- public static <T, R> Function<T, R> _f (@Nonnull final FunctionWithException<? super T, ? extends R> function)
- {
- return t ->
- {
- try
- {
- return function.apply(t);
- }
- catch (Throwable e)
- {
- throw wrappedException(e);
- }
- };
- }
- /***********************************************************************************************************************************************************
- * A wrapper for a {@link Consumer} that catches exceptions and wraps them into {@link RuntimeException}s.
- *
- * @param consumer the {@code Consumer} to wrap.
- * @param <T> the type of the {@code Consumer} argument
- * @return the wrapped {@code Consumer}
- **********************************************************************************************************************************************************/
- @Nonnull
- public static <T> Consumer<T> _c (@Nonnull final ConsumerWithException<? super T> consumer)
- {
- return t ->
- {
- try
- {
- consumer.accept(t);
- }
- catch (Throwable e)
- {
- throw wrappedException(e);
- }
- };
- }
- /***********************************************************************************************************************************************************
- * A wrapper for a {@link Supplier} that catches exceptions and wraps them into {@link RuntimeException}s.
- *
- * @param supplier the {@code Supplier} to wrap.
- * @param <T> the type of the {@code Supplier} argument
- * @return the wrapped {@code Supplier}
- **********************************************************************************************************************************************************/
- @Nonnull
- public static <T> Supplier<T> _s (@Nonnull final SupplierWithException<? extends T> supplier)
- {
- return () ->
- {
- try
- {
- return supplier.get();
- }
- catch (Throwable e)
- {
- throw wrappedException(e);
- }
- };
- }
- /***********************************************************************************************************************************************************
- * A wrapper for a {@link Predicate} that catches exceptions and wraps them into {@link RuntimeException}s.
- *
- * @param predicate the {@code Predicate} to wrap.
- * @param <T> the type of the {@code Predicate} argument
- * @return the wrapped {@code Predicate}
- **********************************************************************************************************************************************************/
- @Nonnull
- public static <T> Predicate<T> _p (@Nonnull final PredicateWithException<? super T> predicate)
- {
- return t ->
- {
- try
- {
- return predicate.test(t);
- }
- catch (Throwable e)
- {
- throw wrappedException(e);
- }
- };
- }
- /***********************************************************************************************************************************************************
- * A wrapper for an equivalent of {@link Runnable} that catches exceptions and wraps them into
- * {@link RuntimeException}s.
- *
- * @param runnable the {@code Runnable} to wrap.
- * @return the wrapped {@code Predicate}
- * @since 3.2-ALPHA-12
- **********************************************************************************************************************************************************/
- @Nonnull
- public static Runnable _r (@Nonnull final RunnableWithException runnable)
- {
- return () ->
- {
- try
- {
- runnable.run();
- }
- catch (Exception e)
- {
- throw wrappedException(e);
- }
- };
- }
- /***********************************************************************************************************************************************************
- * Wraps a throwable with a {@link RuntimeException}. Unchecked exceptions are not wrapped; {@link IOException}
- * is wrapped with {@link UncheckedIOException}.
- *
- * @param e the exception to wrap
- * @return the wrapped exception
- **********************************************************************************************************************************************************/
- @Nonnull
- public static RuntimeException wrappedException (@Nonnull final Throwable e)
- {
- if (e instanceof RuntimeException)
- {
- return (RuntimeException)e;
- }
- if (e instanceof IOException)
- {
- return new UncheckedIOException((IOException)e);
- }
- return new RuntimeException(e);
- }
- }