001/*
002 * Copyright 2022-2025 Revetware LLC.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.soklet.converter;
018
019import javax.annotation.Nonnull;
020import javax.annotation.Nullable;
021import java.lang.reflect.Type;
022import java.util.Optional;
023
024/**
025 * Contract for converting objects from one type to another.
026 * <p>
027 * For example, you might have a {@code ValueConverter<String, List<Integer>>} which converts
028 * text like {@code "1,2,3"} to a list of numbers.
029 * <p>
030 * Value conversion is documented in detail at <a href="https://www.soklet.com/docs/value-conversions">https://www.soklet.com/docs/value-conversions</a>.
031 *
032 * @author <a href="https://www.revetkn.com">Mark Allen</a>
033 */
034public interface ValueConverter<F, T> {
035        /**
036         * Converts {@code from} to an instance of {@code T}.
037         *
038         * @param from the value from which to convert. May be {@code null}
039         * @return the {@code T} representation of {@code from}
040         * @throws ValueConversionException if an error occurs during conversion
041         */
042        @Nonnull
043        Optional<T> convert(@Nullable F from) throws ValueConversionException;
044
045        /**
046         * The 'converting from' type.
047         *
048         * @return the type represented by {@code F}
049         */
050        @Nonnull
051        Type getFromType();
052
053        /**
054         * The 'converting to' type.
055         *
056         * @return the type represented by {@code T}
057         */
058        @Nonnull
059        Type getToType();
060}