/** * 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 (callback) that computes a value based on multiple input values. * @param <T1> the first value type * @param <T2> the second value type * @param <T3> the third value type * @param <T4> the fourth value type * @param <R> the result type */ public interface Function4<T1, T2, T3, T4, R> { /** * Calculate a value based on the input values. * @param t1 the first value * @param t2 the second value * @param t3 the third value * @param t4 the fourth value * @return the result value * @throws Exception on error */ @NonNull R apply(@NonNull T1 t1, @NonNull T2 t2, @NonNull T3 t3, @NonNull T4 t4) throws Exception; }