| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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. |
| */ |
| |
| package org.apache.commons.lang3.function; |
| |
| import java.io.IOException; |
| import java.io.UncheckedIOException; |
| import java.lang.reflect.UndeclaredThrowableException; |
| import java.util.Collection; |
| import java.util.Objects; |
| import java.util.concurrent.Callable; |
| import java.util.function.BiConsumer; |
| import java.util.function.BiFunction; |
| import java.util.function.BiPredicate; |
| import java.util.function.Consumer; |
| import java.util.function.Function; |
| import java.util.function.Predicate; |
| import java.util.function.Supplier; |
| import java.util.stream.Stream; |
| |
| import org.apache.commons.lang3.stream.Streams.FailableStream; |
| |
| /** |
| * This class provides utility functions, and classes for working with the {@code java.util.function} package, or more |
| * generally, with Java 8 lambdas. More specifically, it attempts to address the fact that lambdas are supposed not to |
| * throw Exceptions, at least not checked Exceptions, AKA instances of {@link Exception}. This enforces the use of |
| * constructs like: |
| * |
| * <pre> |
| * Consumer<java.lang.reflect.Method-> consumer = m -> { |
| * try { |
| * m.invoke(o, args); |
| * } catch (Throwable t) { |
| * throw Failable.rethrow(t); |
| * } |
| * }; |
| * </pre> |
| * |
| * <p> |
| * By replacing a {@link java.util.function.Consumer Consumer<O>} with a {@link FailableConsumer |
| * FailableConsumer<O,? extends Throwable>}, this can be written like follows: |
| * </p> |
| * |
| * <pre> |
| * Functions.accept((m) -> m.invoke(o, args)); |
| * </pre> |
| * |
| * <p> |
| * Obviously, the second version is much more concise and the spirit of Lambda expressions is met better than the second |
| * version. |
| * </p> |
| * |
| * @since 3.11 |
| */ |
| public class Failable { |
| |
| /** |
| * Consumes a consumer and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param consumer the consumer to consume |
| * @param object1 the first object to consume by {@code consumer} |
| * @param object2 the second object to consume by {@code consumer} |
| * @param <T> the type of the first argument the consumer accepts |
| * @param <U> the type of the second argument the consumer accepts |
| * @param <E> the type of checked exception the consumer may throw |
| */ |
| public static <T, U, E extends Throwable> void accept(final FailableBiConsumer<T, U, E> consumer, final T object1, |
| final U object2) { |
| run(() -> consumer.accept(object1, object2)); |
| } |
| |
| /** |
| * Consumes a consumer and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param consumer the consumer to consume |
| * @param object the object to consume by {@code consumer} |
| * @param <T> the type the consumer accepts |
| * @param <E> the type of checked exception the consumer may throw |
| */ |
| public static <T, E extends Throwable> void accept(final FailableConsumer<T, E> consumer, final T object) { |
| run(() -> consumer.accept(object)); |
| } |
| |
| /** |
| * Consumes a consumer and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param consumer the consumer to consume |
| * @param value the value to consume by {@code consumer} |
| * @param <E> the type of checked exception the consumer may throw |
| */ |
| public static <E extends Throwable> void accept(final FailableDoubleConsumer<E> consumer, final double value) { |
| run(() -> consumer.accept(value)); |
| } |
| |
| /** |
| * Consumes a consumer and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param consumer the consumer to consume |
| * @param value the value to consume by {@code consumer} |
| * @param <E> the type of checked exception the consumer may throw |
| */ |
| public static <E extends Throwable> void accept(final FailableIntConsumer<E> consumer, final int value) { |
| run(() -> consumer.accept(value)); |
| } |
| |
| /** |
| * Consumes a consumer and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param consumer the consumer to consume |
| * @param value the value to consume by {@code consumer} |
| * @param <E> the type of checked exception the consumer may throw |
| */ |
| public static <E extends Throwable> void accept(final FailableLongConsumer<E> consumer, final long value) { |
| run(() -> consumer.accept(value)); |
| } |
| |
| /** |
| * Applies a function and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param function the function to apply |
| * @param input1 the first input to apply {@code function} on |
| * @param input2 the second input to apply {@code function} on |
| * @param <T> the type of the first argument the function accepts |
| * @param <U> the type of the second argument the function accepts |
| * @param <R> the return type of the function |
| * @param <E> the type of checked exception the function may throw |
| * @return the value returned from the function |
| */ |
| public static <T, U, R, E extends Throwable> R apply(final FailableBiFunction<T, U, R, E> function, final T input1, |
| final U input2) { |
| return get(() -> function.apply(input1, input2)); |
| } |
| |
| /** |
| * Applies a function and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param function the function to apply |
| * @param input the input to apply {@code function} on |
| * @param <T> the type of the argument the function accepts |
| * @param <R> the return type of the function |
| * @param <E> the type of checked exception the function may throw |
| * @return the value returned from the function |
| */ |
| public static <T, R, E extends Throwable> R apply(final FailableFunction<T, R, E> function, final T input) { |
| return get(() -> function.apply(input)); |
| } |
| |
| /** |
| * Applies a function and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param function the function to apply |
| * @param left the first input to apply {@code function} on |
| * @param right the second input to apply {@code function} on |
| * @param <E> the type of checked exception the function may throw |
| * @return the value returned from the function |
| */ |
| public static <E extends Throwable> double applyAsDouble(final FailableDoubleBinaryOperator<E> function, |
| final double left, final double right) { |
| return getAsDouble(() -> function.applyAsDouble(left, right)); |
| } |
| |
| /** |
| * Converts the given {@link FailableBiConsumer} into a standard {@link BiConsumer}. |
| * |
| * @param <T> the type of the first argument of the consumers |
| * @param <U> the type of the second argument of the consumers |
| * @param consumer a failable {@code BiConsumer} |
| * @return a standard {@code BiConsumer} |
| */ |
| public static <T, U> BiConsumer<T, U> asBiConsumer(final FailableBiConsumer<T, U, ?> consumer) { |
| return (input1, input2) -> accept(consumer, input1, input2); |
| } |
| |
| /** |
| * Converts the given {@link FailableBiFunction} into a standard {@link BiFunction}. |
| * |
| * @param <T> the type of the first argument of the input of the functions |
| * @param <U> the type of the second argument of the input of the functions |
| * @param <R> the type of the output of the functions |
| * @param function a {@code FailableBiFunction} |
| * @return a standard {@code BiFunction} |
| */ |
| public static <T, U, R> BiFunction<T, U, R> asBiFunction(final FailableBiFunction<T, U, R, ?> function) { |
| return (input1, input2) -> apply(function, input1, input2); |
| } |
| |
| /** |
| * Converts the given {@link FailableBiPredicate} into a standard {@link BiPredicate}. |
| * |
| * @param <T> the type of the first argument used by the predicates |
| * @param <U> the type of the second argument used by the predicates |
| * @param predicate a {@code FailableBiPredicate} |
| * @return a standard {@code BiPredicate} |
| */ |
| public static <T, U> BiPredicate<T, U> asBiPredicate(final FailableBiPredicate<T, U, ?> predicate) { |
| return (input1, input2) -> test(predicate, input1, input2); |
| } |
| |
| /** |
| * Converts the given {@link FailableCallable} into a standard {@link Callable}. |
| * |
| * @param <V> the type used by the callables |
| * @param callable a {@code FailableCallable} |
| * @return a standard {@code Callable} |
| */ |
| public static <V> Callable<V> asCallable(final FailableCallable<V, ?> callable) { |
| return () -> call(callable); |
| } |
| |
| /** |
| * Converts the given {@link FailableConsumer} into a standard {@link Consumer}. |
| * |
| * @param <T> the type used by the consumers |
| * @param consumer a {@code FailableConsumer} |
| * @return a standard {@code Consumer} |
| */ |
| public static <T> Consumer<T> asConsumer(final FailableConsumer<T, ?> consumer) { |
| return input -> accept(consumer, input); |
| } |
| |
| /** |
| * Converts the given {@link FailableFunction} into a standard {@link Function}. |
| * |
| * @param <T> the type of the input of the functions |
| * @param <R> the type of the output of the functions |
| * @param function a {code FailableFunction} |
| * @return a standard {@code Function} |
| */ |
| public static <T, R> Function<T, R> asFunction(final FailableFunction<T, R, ?> function) { |
| return input -> apply(function, input); |
| } |
| |
| /** |
| * Converts the given {@link FailablePredicate} into a standard {@link Predicate}. |
| * |
| * @param <T> the type used by the predicates |
| * @param predicate a {@code FailablePredicate} |
| * @return a standard {@code Predicate} |
| */ |
| public static <T> Predicate<T> asPredicate(final FailablePredicate<T, ?> predicate) { |
| return input -> test(predicate, input); |
| } |
| |
| /** |
| * Converts the given {@link FailableRunnable} into a standard {@link Runnable}. |
| * |
| * @param runnable a {@code FailableRunnable} |
| * @return a standard {@code Runnable} |
| */ |
| public static Runnable asRunnable(final FailableRunnable<?> runnable) { |
| return () -> run(runnable); |
| } |
| |
| /** |
| * Converts the given {@link FailableSupplier} into a standard {@link Supplier}. |
| * |
| * @param <T> the type supplied by the suppliers |
| * @param supplier a {@code FailableSupplier} |
| * @return a standard {@code Supplier} |
| */ |
| public static <T> Supplier<T> asSupplier(final FailableSupplier<T, ?> supplier) { |
| return () -> get(supplier); |
| } |
| |
| /** |
| * Calls a callable and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param callable the callable to call |
| * @param <V> the return type of the callable |
| * @param <E> the type of checked exception the callable may throw |
| * @return the value returned from the callable |
| */ |
| public static <V, E extends Throwable> V call(final FailableCallable<V, E> callable) { |
| return get(callable::call); |
| } |
| |
| /** |
| * Invokes a supplier, and returns the result. |
| * |
| * @param supplier The supplier to invoke. |
| * @param <T> The suppliers output type. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The object, which has been created by the supplier |
| */ |
| public static <T, E extends Throwable> T get(final FailableSupplier<T, E> supplier) { |
| try { |
| return supplier.get(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Invokes a boolean supplier, and returns the result. |
| * |
| * @param supplier The boolean supplier to invoke. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The boolean, which has been created by the supplier |
| */ |
| public static <E extends Throwable> boolean getAsBoolean(final FailableBooleanSupplier<E> supplier) { |
| try { |
| return supplier.getAsBoolean(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Invokes a double supplier, and returns the result. |
| * |
| * @param supplier The double supplier to invoke. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The double, which has been created by the supplier |
| */ |
| public static <E extends Throwable> double getAsDouble(final FailableDoubleSupplier<E> supplier) { |
| try { |
| return supplier.getAsDouble(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Invokes an int supplier, and returns the result. |
| * |
| * @param supplier The int supplier to invoke. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The int, which has been created by the supplier |
| */ |
| public static <E extends Throwable> int getAsInt(final FailableIntSupplier<E> supplier) { |
| try { |
| return supplier.getAsInt(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Invokes a long supplier, and returns the result. |
| * |
| * @param supplier The long supplier to invoke. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The long, which has been created by the supplier |
| */ |
| public static <E extends Throwable> long getAsLong(final FailableLongSupplier<E> supplier) { |
| try { |
| return supplier.getAsLong(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Invokes a short supplier, and returns the result. |
| * |
| * @param supplier The short supplier to invoke. |
| * @param <E> The type of checked exception, which the supplier can throw. |
| * @return The short, which has been created by the supplier |
| */ |
| public static <E extends Throwable> short getAsShort(final FailableShortSupplier<E> supplier) { |
| try { |
| return supplier.getAsShort(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * <p> |
| * Rethrows a {@link Throwable} as an unchecked exception. If the argument is already unchecked, namely a |
| * {@code RuntimeException} or {@code Error} then the argument will be rethrown without modification. If the |
| * exception is {@code IOException} then it will be wrapped into a {@code UncheckedIOException}. In every other |
| * cases the exception will be wrapped into a {@code |
| * UndeclaredThrowableException} |
| * </p> |
| * |
| * <p> |
| * Note that there is a declared return type for this method, even though it never returns. The reason for that is |
| * to support the usual pattern: |
| * </p> |
| * |
| * <pre> |
| * throw rethrow(myUncheckedException); |
| * </pre> |
| * |
| * <p> |
| * instead of just calling the method. This pattern may help the Java compiler to recognize that at that point an |
| * exception will be thrown and the code flow analysis will not demand otherwise mandatory commands that could |
| * follow the method call, like a {@code return} statement from a value returning method. |
| * </p> |
| * |
| * @param throwable The throwable to rethrow ossibly wrapped into an unchecked exception |
| * @return Never returns anything, this method never terminates normally. |
| */ |
| public static RuntimeException rethrow(final Throwable throwable) { |
| Objects.requireNonNull(throwable, "throwable"); |
| if (throwable instanceof RuntimeException) { |
| throw (RuntimeException) throwable; |
| } |
| if (throwable instanceof Error) { |
| throw (Error) throwable; |
| } |
| if (throwable instanceof IOException) { |
| throw new UncheckedIOException((IOException) throwable); |
| } |
| throw new UndeclaredThrowableException(throwable); |
| } |
| |
| /** |
| * Runs a runnable and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param runnable The runnable to run |
| * @param <E> the type of checked exception the runnable may throw |
| */ |
| public static <E extends Throwable> void run(final FailableRunnable<E> runnable) { |
| try { |
| runnable.run(); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| |
| /** |
| * Converts the given collection into a {@link FailableStream}. The {@link FailableStream} consists of the |
| * collections elements. Shortcut for |
| * |
| * <pre> |
| * Functions.stream(collection.stream()); |
| * </pre> |
| * |
| * @param collection The collection, which is being converted into a {@link FailableStream}. |
| * @param <E> The collections element type. (In turn, the result streams element type.) |
| * @return The created {@link FailableStream}. |
| */ |
| public static <E> FailableStream<E> stream(final Collection<E> collection) { |
| return new FailableStream<>(collection.stream()); |
| } |
| |
| /** |
| * Converts the given stream into a {@link FailableStream}. The {@link FailableStream} consists of the same |
| * elements, than the input stream. However, failable lambdas, like {@link FailablePredicate}, |
| * {@link FailableFunction}, and {@link FailableConsumer} may be applied, rather than {@link Predicate}, |
| * {@link Function}, {@link Consumer}, etc. |
| * |
| * @param stream The stream, which is being converted into a {@link FailableStream}. |
| * @param <T> The streams element type. |
| * @return The created {@link FailableStream}. |
| */ |
| public static <T> FailableStream<T> stream(final Stream<T> stream) { |
| return new FailableStream<>(stream); |
| } |
| |
| /** |
| * Tests a predicate and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param predicate the predicate to test |
| * @param object1 the first input to test by {@code predicate} |
| * @param object2 the second input to test by {@code predicate} |
| * @param <T> the type of the first argument the predicate tests |
| * @param <U> the type of the second argument the predicate tests |
| * @param <E> the type of checked exception the predicate may throw |
| * @return the boolean value returned by the predicate |
| */ |
| public static <T, U, E extends Throwable> boolean test(final FailableBiPredicate<T, U, E> predicate, |
| final T object1, final U object2) { |
| return getAsBoolean(() -> predicate.test(object1, object2)); |
| } |
| |
| /** |
| * Tests a predicate and rethrows any exception as a {@link RuntimeException}. |
| * |
| * @param predicate the predicate to test |
| * @param object the input to test by {@code predicate} |
| * @param <T> the type of argument the predicate tests |
| * @param <E> the type of checked exception the predicate may throw |
| * @return the boolean value returned by the predicate |
| */ |
| public static <T, E extends Throwable> boolean test(final FailablePredicate<T, E> predicate, final T object) { |
| return getAsBoolean(() -> predicate.test(object)); |
| } |
| |
| /** |
| * A simple try-with-resources implementation, that can be used, if your objects do not implement the |
| * {@link AutoCloseable} interface. The method executes the {@code action}. The method guarantees, that <em>all</em> |
| * the {@code resources} are being executed, in the given order, afterwards, and regardless of success, or failure. |
| * If either the original action, or any of the resource action fails, then the <em>first</em> failure (AKA |
| * {@link Throwable} is rethrown. Example use: |
| * |
| * <pre> |
| * final FileInputStream fis = new FileInputStream("my.file"); |
| * Functions.tryWithResources(useInputStream(fis), null, () -> fis.close()); |
| * </pre> |
| * |
| * @param action The action to execute. This object <em>will</em> always be invoked. |
| * @param errorHandler An optional error handler, which will be invoked finally, if any error occurred. The error |
| * handler will receive the first error, AKA {@link Throwable}. |
| * @param resources The resource actions to execute. <em>All</em> resource actions will be invoked, in the given |
| * order. A resource action is an instance of {@link FailableRunnable}, which will be executed. |
| * @see #tryWithResources(FailableRunnable, FailableRunnable...) |
| */ |
| @SafeVarargs |
| public static void tryWithResources(final FailableRunnable<? extends Throwable> action, |
| final FailableConsumer<Throwable, ? extends Throwable> errorHandler, |
| final FailableRunnable<? extends Throwable>... resources) { |
| final FailableConsumer<Throwable, ? extends Throwable> actualErrorHandler; |
| if (errorHandler == null) { |
| actualErrorHandler = Failable::rethrow; |
| } else { |
| actualErrorHandler = errorHandler; |
| } |
| if (resources != null) { |
| for (final FailableRunnable<? extends Throwable> failableRunnable : resources) { |
| Objects.requireNonNull(failableRunnable, "runnable"); |
| } |
| } |
| Throwable th = null; |
| try { |
| action.run(); |
| } catch (final Throwable t) { |
| th = t; |
| } |
| if (resources != null) { |
| for (final FailableRunnable<?> runnable : resources) { |
| try { |
| runnable.run(); |
| } catch (final Throwable t) { |
| if (th == null) { |
| th = t; |
| } |
| } |
| } |
| } |
| if (th != null) { |
| try { |
| actualErrorHandler.accept(th); |
| } catch (final Throwable t) { |
| throw rethrow(t); |
| } |
| } |
| } |
| |
| /** |
| * A simple try-with-resources implementation, that can be used, if your objects do not implement the |
| * {@link AutoCloseable} interface. The method executes the {@code action}. The method guarantees, that <em>all</em> |
| * the {@code resources} are being executed, in the given order, afterwards, and regardless of success, or failure. |
| * If either the original action, or any of the resource action fails, then the <em>first</em> failure (AKA |
| * {@link Throwable} is rethrown. Example use: |
| * |
| * <pre> |
| * final FileInputStream fis = new FileInputStream("my.file"); |
| * Functions.tryWithResources(useInputStream(fis), () -> fis.close()); |
| * </pre> |
| * |
| * @param action The action to execute. This object <em>will</em> always be invoked. |
| * @param resources The resource actions to execute. <em>All</em> resource actions will be invoked, in the given |
| * order. A resource action is an instance of {@link FailableRunnable}, which will be executed. |
| * @see #tryWithResources(FailableRunnable, FailableConsumer, FailableRunnable...) |
| */ |
| @SafeVarargs |
| public static void tryWithResources(final FailableRunnable<? extends Throwable> action, |
| final FailableRunnable<? extends Throwable>... resources) { |
| tryWithResources(action, null, resources); |
| } |
| |
| private Failable() { |
| // empty |
| } |
| |
| } |