001/* 002 * Copyright 2012-2017 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 * 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 org.springframework.boot.context.annotation; 018 019import java.util.Set; 020 021import org.springframework.beans.factory.Aware; 022import org.springframework.context.ApplicationContext; 023import org.springframework.context.annotation.ImportBeanDefinitionRegistrar; 024import org.springframework.context.annotation.ImportSelector; 025import org.springframework.core.type.AnnotationMetadata; 026 027/** 028 * Interface that can be implemented by {@link ImportSelector} and 029 * {@link ImportBeanDefinitionRegistrar} implementations when they can determine imports 030 * early. The {@link ImportSelector} and {@link ImportBeanDefinitionRegistrar} interfaces 031 * are quite flexible which can make it hard to tell exactly what bean definitions they 032 * will add. This interface should be used when an implementation consistently results in 033 * the same imports, given the same source. 034 * <p> 035 * Using {@link DeterminableImports} is particularly useful when working with Spring's 036 * testing support. It allows for better generation of {@link ApplicationContext} cache 037 * keys. 038 * 039 * @author Phillip Webb 040 * @author Andy Wilkinson 041 * @since 1.5.0 042 */ 043@FunctionalInterface 044public interface DeterminableImports { 045 046 /** 047 * Return a set of objects that represent the imports. Objects within the returned 048 * {@code Set} must implement a valid {@link Object#hashCode() hashCode} and 049 * {@link Object#equals(Object) equals}. 050 * <p> 051 * Imports from multiple {@link DeterminableImports} instances may be combined by the 052 * caller to create a complete set. 053 * <p> 054 * Unlike {@link ImportSelector} and {@link ImportBeanDefinitionRegistrar} any 055 * {@link Aware} callbacks will not be invoked before this method is called. 056 * @param metadata the source meta-data 057 * @return a key representing the annotations that actually drive the import 058 */ 059 Set<Object> determineImports(AnnotationMetadata metadata); 060 061}