| /* |
| * 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.brooklyn.util.guava; |
| |
| import java.util.concurrent.Callable; |
| |
| import org.apache.brooklyn.util.guava.IfFunctions.IfFunctionBuilderApplyingFirst; |
| |
| import com.google.common.base.Function; |
| import com.google.common.base.Functions; |
| import com.google.common.base.Predicate; |
| import com.google.common.base.Supplier; |
| import com.google.common.base.Suppliers; |
| |
| public class Functionals { |
| |
| /** applies f1 to the input, then the result of that is passed to f2 (note opposite semantics to {@link Functions#compose(Function, Function)} */ |
| public static <A,B,C> Function<A,C> chain(final Function<A,? extends B> f1, final Function<B,C> f2) { |
| return Functions.compose(f2, f1); |
| } |
| |
| /** applies f1 to the input, then f2 to that result, then f3 to that result */ |
| public static <A,B,C,D> Function<A,D> chain(final Function<A,? extends B> f1, final Function<B,? extends C> f2, final Function<C,D> f3) { |
| return chain(f1, chain(f2, f3)); |
| } |
| |
| /** applies f1 to the input, then f2 to that result, then f3 to that result, then f4 to that result */ |
| public static <A,B,C,D,E> Function<A,E> chain(final Function<A,? extends B> f1, final Function<B,? extends C> f2, final Function<C,? extends D> f3, final Function<D,E> f4) { |
| return chain(f1, chain(f2, chain(f3, f4))); |
| } |
| |
| /** @see IfFunctions */ |
| public static <I> IfFunctionBuilderApplyingFirst<I> ifEquals(I test) { |
| return IfFunctions.ifEquals(test); |
| } |
| |
| /** @see IfFunctions */ |
| public static <I> IfFunctionBuilderApplyingFirst<I> ifNotEquals(I test) { |
| return IfFunctions.ifNotEquals(test); |
| } |
| |
| /** @see IfFunctions */ |
| public static <I> IfFunctionBuilderApplyingFirst<I> ifPredicate(Predicate<I> test) { |
| return IfFunctions.ifPredicate(test); |
| } |
| |
| /** like guava equivalent but parametrises the input generic type, and allows tostring to be customised */ |
| public static final class ConstantFunction<I, O> implements Function<I, O> { |
| private final O constant; |
| private Object toStringDescription; |
| |
| public ConstantFunction(O constant) { |
| this(constant, null); |
| } |
| public ConstantFunction(O constant, Object toStringDescription) { |
| this.constant = constant; |
| this.toStringDescription = toStringDescription; |
| } |
| |
| @Override |
| public O apply(I input) { |
| return constant; |
| } |
| |
| @Override |
| public String toString() { |
| return toStringDescription==null ? "constant("+constant+")" : toStringDescription.toString(); |
| } |
| } |
| |
| /** like guava {@link Functions#forSupplier(Supplier)} but parametrises the input generic type */ |
| public static <I,O> Function<I,O> function(final Supplier<O> supplier) { |
| class SupplierAsFunction implements Function<I,O> { |
| @Override public O apply(I input) { |
| return supplier.get(); |
| } |
| @Override public String toString() { |
| return "function("+supplier+")"; |
| } |
| } |
| return new SupplierAsFunction(); |
| } |
| |
| public static <I> Function<I,Void> function(final Runnable runnable) { |
| class RunnableAsFunction implements Function<I,Void> { |
| @Override public Void apply(I input) { |
| runnable.run(); |
| return null; |
| } |
| } |
| return new RunnableAsFunction(); |
| } |
| |
| public static Runnable runnable(final Supplier<?> supplier) { |
| class SupplierAsRunnable implements Runnable { |
| @Override |
| public void run() { |
| supplier.get(); |
| } |
| } |
| return new SupplierAsRunnable(); |
| } |
| |
| public static <T> Callable<T> callable(final Supplier<T> supplier) { |
| class SupplierAsCallable implements Callable<T> { |
| @Override |
| public T call() { |
| return supplier.get(); |
| } |
| @Override |
| public String toString() { |
| return "callable("+supplier+")"; |
| } |
| } |
| return new SupplierAsCallable(); |
| } |
| public static <T,U> Callable<U> callable(Function<T,U> f, T x) { |
| return callable(Suppliers.compose(f, Suppliers.ofInstance(x))); |
| } |
| |
| public static <T> Predicate<T> predicate(final Function<T,Boolean> f) { |
| class FunctionAsPredicate implements Predicate<T> { |
| @Override |
| public boolean apply(T input) { |
| return f.apply(input); |
| } |
| @Override |
| public String toString() { |
| return "predicate("+f+")"; |
| } |
| } |
| return new FunctionAsPredicate(); |
| } |
| |
| } |