| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * 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. |
| */ |
| |
| package com.android.internal.util; |
| |
| import android.os.RemoteException; |
| import android.util.ExceptionUtils; |
| |
| import java.util.function.Consumer; |
| import java.util.function.Function; |
| import java.util.function.Supplier; |
| |
| /** |
| * Utilities specific to functional programming |
| */ |
| public class FunctionalUtils { |
| private FunctionalUtils() {} |
| |
| /** |
| * Converts a lambda expression that throws a checked exception(s) into a regular |
| * {@link Consumer} by propagating any checked exceptions as {@link RuntimeException} |
| */ |
| public static <T> Consumer<T> uncheckExceptions(ThrowingConsumer<T> action) { |
| return action; |
| } |
| |
| /** |
| * @see #uncheckExceptions(ThrowingConsumer) |
| */ |
| public static <I, O> Function<I, O> uncheckExceptions(ThrowingFunction<I, O> action) { |
| return action; |
| } |
| |
| /** |
| * @see #uncheckExceptions(ThrowingConsumer) |
| */ |
| public static Runnable uncheckExceptions(ThrowingRunnable action) { |
| return action; |
| } |
| |
| /** |
| * @see #uncheckExceptions(ThrowingConsumer) |
| */ |
| public static <T> Supplier<T> uncheckExceptions(ThrowingSupplier<T> action) { |
| return action; |
| } |
| |
| /** |
| * Wraps a given {@code action} into one that ignores any {@link RemoteException}s |
| */ |
| public static <T> Consumer<T> ignoreRemoteException(RemoteExceptionIgnoringConsumer<T> action) { |
| return action; |
| } |
| |
| /** |
| * Wraps the given {@link ThrowingRunnable} into one that handles any exceptions using the |
| * provided {@code handler} |
| */ |
| public static Runnable handleExceptions(ThrowingRunnable r, Consumer<Throwable> handler) { |
| return () -> { |
| try { |
| r.run(); |
| } catch (Throwable t) { |
| handler.accept(t); |
| } |
| }; |
| } |
| |
| /** |
| * An equivalent of {@link Runnable} that allows throwing checked exceptions |
| * |
| * This can be used to specify a lambda argument without forcing all the checked exceptions |
| * to be handled within it |
| */ |
| @FunctionalInterface |
| @SuppressWarnings("FunctionalInterfaceMethodChanged") |
| public interface ThrowingRunnable extends Runnable { |
| void runOrThrow() throws Exception; |
| |
| @Override |
| default void run() { |
| try { |
| runOrThrow(); |
| } catch (Exception ex) { |
| throw ExceptionUtils.propagate(ex); |
| } |
| } |
| } |
| |
| /** |
| * An equivalent of {@link Supplier} that allows throwing checked exceptions |
| * |
| * This can be used to specify a lambda argument without forcing all the checked exceptions |
| * to be handled within it |
| */ |
| @FunctionalInterface |
| @SuppressWarnings("FunctionalInterfaceMethodChanged") |
| public interface ThrowingSupplier<T> extends Supplier<T> { |
| T getOrThrow() throws Exception; |
| |
| @Override |
| default T get() { |
| try { |
| return getOrThrow(); |
| } catch (Exception ex) { |
| throw ExceptionUtils.propagate(ex); |
| } |
| } |
| } |
| /** |
| * A {@link Consumer} that allows throwing checked exceptions from its single abstract method. |
| * |
| * Can be used together with {@link #uncheckExceptions} to effectively turn a lambda expression |
| * that throws a checked exception into a regular {@link Consumer} |
| */ |
| @FunctionalInterface |
| @SuppressWarnings("FunctionalInterfaceMethodChanged") |
| public interface ThrowingConsumer<T> extends Consumer<T> { |
| void acceptOrThrow(T t) throws Exception; |
| |
| @Override |
| default void accept(T t) { |
| try { |
| acceptOrThrow(t); |
| } catch (Exception ex) { |
| throw ExceptionUtils.propagate(ex); |
| } |
| } |
| } |
| |
| /** |
| * A {@link Consumer} that automatically ignores any {@link RemoteException}s. |
| * |
| * Used by {@link #ignoreRemoteException} |
| */ |
| @FunctionalInterface |
| @SuppressWarnings("FunctionalInterfaceMethodChanged") |
| public interface RemoteExceptionIgnoringConsumer<T> extends Consumer<T> { |
| void acceptOrThrow(T t) throws RemoteException; |
| |
| @Override |
| default void accept(T t) { |
| try { |
| acceptOrThrow(t); |
| } catch (RemoteException ex) { |
| // ignore |
| } |
| } |
| } |
| |
| /** |
| * A {@link Function} that allows throwing checked exceptions from its single abstract method. |
| * |
| * Can be used together with {@link #uncheckExceptions} to effectively turn a lambda expression |
| * that throws a checked exception into a regular {@link Function} |
| * |
| * @param <T> see {@link Function} |
| * @param <R> see {@link Function} |
| */ |
| @FunctionalInterface |
| @SuppressWarnings("FunctionalInterfaceMethodChanged") |
| public interface ThrowingFunction<T, R> extends Function<T, R> { |
| /** @see ThrowingFunction */ |
| R applyOrThrow(T t) throws Exception; |
| |
| @Override |
| default R apply(T t) { |
| try { |
| return applyOrThrow(t); |
| } catch (Exception ex) { |
| throw ExceptionUtils.propagate(ex); |
| } |
| } |
| } |
| } |