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.web.servlet; 018 019import java.lang.annotation.Documented; 020import java.lang.annotation.ElementType; 021import java.lang.annotation.Retention; 022import java.lang.annotation.RetentionPolicy; 023import java.lang.annotation.Target; 024 025import javax.servlet.annotation.WebFilter; 026import javax.servlet.annotation.WebListener; 027import javax.servlet.annotation.WebServlet; 028 029import org.springframework.context.annotation.Import; 030import org.springframework.core.annotation.AliasFor; 031 032/** 033 * Enables scanning for Servlet components ({@link WebFilter filters}, {@link WebServlet 034 * servlets}, and {@link WebListener listeners}). Scanning is only performed when using an 035 * embedded web server. 036 * <p> 037 * Typically, one of {@code value}, {@code basePackages}, or {@code basePackageClasses} 038 * should be specified to control the packages to be scanned for components. In their 039 * absence, scanning will be performed from the package of the class with the annotation. 040 * 041 * @author Andy Wilkinson 042 * @since 1.3.0 043 * @see WebServlet 044 * @see WebFilter 045 * @see WebListener 046 */ 047@Target(ElementType.TYPE) 048@Retention(RetentionPolicy.RUNTIME) 049@Documented 050@Import(ServletComponentScanRegistrar.class) 051public @interface ServletComponentScan { 052 053 /** 054 * Alias for the {@link #basePackages()} attribute. Allows for more concise annotation 055 * declarations e.g.: {@code @ServletComponentScan("org.my.pkg")} instead of 056 * {@code @ServletComponentScan(basePackages="org.my.pkg")}. 057 * @return the base packages to scan 058 */ 059 @AliasFor("basePackages") 060 String[] value() default {}; 061 062 /** 063 * Base packages to scan for annotated servlet components. {@link #value()} is an 064 * alias for (and mutually exclusive with) this attribute. 065 * <p> 066 * Use {@link #basePackageClasses()} for a type-safe alternative to String-based 067 * package names. 068 * @return the base packages to scan 069 */ 070 @AliasFor("value") 071 String[] basePackages() default {}; 072 073 /** 074 * Type-safe alternative to {@link #basePackages()} for specifying the packages to 075 * scan for annotated servlet components. The package of each class specified will be 076 * scanned. 077 * @return classes from the base packages to scan 078 */ 079 Class<?>[] basePackageClasses() default {}; 080 081}