001/*
002 * Copyright 2002-2016 the original author or authors.
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 *      https://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 org.springframework.core.convert.converter;
018
019import org.springframework.lang.Nullable;
020
021/**
022 * A converter converts a source object of type {@code S} to a target of type {@code T}.
023 *
024 * <p>Implementations of this interface are thread-safe and can be shared.
025 *
026 * <p>Implementations may additionally implement {@link ConditionalConverter}.
027 *
028 * @author Keith Donald
029 * @since 3.0
030 * @param <S> the source type
031 * @param <T> the target type
032 */
033@FunctionalInterface
034public interface Converter<S, T> {
035
036        /**
037         * Convert the source object of type {@code S} to target type {@code T}.
038         * @param source the source object to convert, which must be an instance of {@code S} (never {@code null})
039         * @return the converted object, which must be an instance of {@code T} (potentially {@code null})
040         * @throws IllegalArgumentException if the source cannot be converted to the desired target type
041         */
042        @Nullable
043        T convert(S source);
044
045}