/** * Copyright (c) 2016-present, RxJava Contributors. * * 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 io.reactivex.functions; import io.reactivex.annotations.NonNull; /** * A functional interface that takes a value and returns another value, possibly with a * different type and allows throwing a checked exception. * * @param <T> the input value type * @param <R> the output value type */ public interface Function<T, R> { /** * Apply some calculation to the input value and return some other value. * @param t the input value * @return the output value * @throws Exception on error */ R apply(@NonNull T t) throws Exception; }