001/*
002 * Copyright 2002-2014 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.core.convert.TypeDescriptor;
020
021/**
022 * Allows a {@link Converter}, {@link GenericConverter} or {@link ConverterFactory} to
023 * conditionally execute based on attributes of the {@code source} and {@code target}
024 * {@link TypeDescriptor}.
025 *
026 * <p>Often used to selectively match custom conversion logic based on the presence of a
027 * field or class-level characteristic, such as an annotation or method. For example, when
028 * converting from a String field to a Date field, an implementation might return
029 * {@code true} if the target field has also been annotated with {@code @DateTimeFormat}.
030 *
031 * <p>As another example, when converting from a String field to an {@code Account} field,
032 * an implementation might return {@code true} if the target Account class defines a
033 * {@code public static findAccount(String)} method.
034 *
035 * @author Phillip Webb
036 * @author Keith Donald
037 * @since 3.2
038 * @see Converter
039 * @see GenericConverter
040 * @see ConverterFactory
041 * @see ConditionalGenericConverter
042 */
043public interface ConditionalConverter {
044
045        /**
046         * Should the conversion from {@code sourceType} to {@code targetType} currently under
047         * consideration be selected?
048         * @param sourceType the type descriptor of the field we are converting from
049         * @param targetType the type descriptor of the field we are converting to
050         * @return true if conversion should be performed, false otherwise
051         */
052        boolean matches(TypeDescriptor sourceType, TypeDescriptor targetType);
053
054}