com.caoccao.javet.interfaces.IJavaFunction Maven / Gradle / Ivy
/*
* Copyright (c) 2021-2024. caoccao.com Sam Cao
*
* 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.caoccao.javet.interfaces;
import java.util.Objects;
/**
* Represents a function that accepts one argument and produces a result.
*
* It is a polyfill to the built-in Supplier for Android compatibility.
*
* @param the type of the input to the function
* @param the type of the result of the function
* @see java.util.function.Function
* @since 1.0.3
*/
@FunctionalInterface
public interface IJavaFunction {
/**
* Returns a function that always returns its input argument.
*
* @param the type of the input and output objects to the function
* @return a function that always returns its input argument
* @since 1.0.3
*/
static IJavaFunction identity() {
return t -> t;
}
/**
* Returns a composed function that first applies this function to
* its input, and then applies the {@code after} function to the result.
* If evaluation of either function throws an exception, it is relayed to
* the caller of the composed function.
*
* @param the type of output of the {@code after} function, and of the
* composed function
* @param after the function to apply after this function is applied
* @return a composed function that first applies this function and then
* applies the {@code after} function
* @throws NullPointerException if after is null
* @see #compose(IJavaFunction)
* @since 1.0.3
*/
default IJavaFunction andThen(IJavaFunction after) {
Objects.requireNonNull(after);
return (T t) -> after.apply(apply(t));
}
/**
* Applies this function to the given argument.
*
* @param t the function argument
* @return the function result
* @since 1.0.3
*/
R apply(T t);
/**
* Returns a composed function that first applies the {@code before}
* function to its input, and then applies this function to the result.
* If evaluation of either function throws an exception, it is relayed to
* the caller of the composed function.
*
* @param the type of input to the {@code before} function, and to the
* composed function
* @param before the function to apply before this function is applied
* @return a composed function that first applies the {@code before}
* function and then applies this function
* @throws NullPointerException if before is null
* @see #andThen(IJavaFunction)
* @since 1.0.3
*/
default IJavaFunction compose(IJavaFunction before) {
Objects.requireNonNull(before);
return (V v) -> apply(before.apply(v));
}
}