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* Copyright 2002-2020 the original author or authors.
*
* 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
*
* https://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
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package org.springframework.context.annotation;
import java.util.function.Predicate;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.lang.Nullable;
Interface to be implemented by types that determine which @Configuration class(es) should be imported based on a given selection criteria, usually one or more annotation attributes. An ImportSelector may implement any of the following Aware interfaces, and their respective methods will be called prior to selectImports:
Alternatively, the class may provide a single constructor with one or more of
the following supported parameter types:
ImportSelector implementations are usually processed in the same way as regular @Import annotations, however, it is also possible to defer selection of imports until all @Configuration classes have been processed (see DeferredImportSelector for details).
Author: Chris Beams, Juergen Hoeller See Also: Since: 3.1
/**
* Interface to be implemented by types that determine which @{@link Configuration}
* class(es) should be imported based on a given selection criteria, usually one or
* more annotation attributes.
*
* <p>An {@link ImportSelector} may implement any of the following
* {@link org.springframework.beans.factory.Aware Aware} interfaces,
* and their respective methods will be called prior to {@link #selectImports}:
* <ul>
* <li>{@link org.springframework.context.EnvironmentAware EnvironmentAware}</li>
* <li>{@link org.springframework.beans.factory.BeanFactoryAware BeanFactoryAware}</li>
* <li>{@link org.springframework.beans.factory.BeanClassLoaderAware BeanClassLoaderAware}</li>
* <li>{@link org.springframework.context.ResourceLoaderAware ResourceLoaderAware}</li>
* </ul>
*
* <p>Alternatively, the class may provide a single constructor with one or more of
* the following supported parameter types:
* <ul>
* <li>{@link org.springframework.core.env.Environment Environment}</li>
* <li>{@link org.springframework.beans.factory.BeanFactory BeanFactory}</li>
* <li>{@link java.lang.ClassLoader ClassLoader}</li>
* <li>{@link org.springframework.core.io.ResourceLoader ResourceLoader}</li>
* </ul>
*
* <p>{@code ImportSelector} implementations are usually processed in the same way
* as regular {@code @Import} annotations, however, it is also possible to defer
* selection of imports until all {@code @Configuration} classes have been processed
* (see {@link DeferredImportSelector} for details).
*
* @author Chris Beams
* @author Juergen Hoeller
* @since 3.1
* @see DeferredImportSelector
* @see Import
* @see ImportBeanDefinitionRegistrar
* @see Configuration
*/
public interface ImportSelector {
Select and return the names of which class(es) should be imported based on the AnnotationMetadata of the importing @Configuration class. Returns: the class names, or an empty array if none
/**
* Select and return the names of which class(es) should be imported based on
* the {@link AnnotationMetadata} of the importing @{@link Configuration} class.
* @return the class names, or an empty array if none
*/
String[] selectImports(AnnotationMetadata importingClassMetadata);
Return a predicate for excluding classes from the import candidates, to be
transitively applied to all classes found through this selector's imports.
If this predicate returns true for a given fully-qualified class name, said class will not be considered as an imported configuration class, bypassing class file loading as well as metadata introspection.
Returns: the filter predicate for fully-qualified candidate class names of transitively imported configuration classes, or null if none Since: 5.2.4
/**
* Return a predicate for excluding classes from the import candidates, to be
* transitively applied to all classes found through this selector's imports.
* <p>If this predicate returns {@code true} for a given fully-qualified
* class name, said class will not be considered as an imported configuration
* class, bypassing class file loading as well as metadata introspection.
* @return the filter predicate for fully-qualified candidate class names
* of transitively imported configuration classes, or {@code null} if none
* @since 5.2.4
*/
@Nullable
default Predicate<String> getExclusionFilter() {
return null;
}
}