Java tutorial
/* * Copyright 2002-2018 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 * limitations under the License. */ package org.springframework.context.annotation; import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; import org.springframework.core.env.AbstractEnvironment; import org.springframework.core.env.ConfigurableEnvironment; import org.springframework.core.env.Profiles; /** * Indicates that a component is eligible for registration when one or more * {@linkplain #value specified profiles} are active. * * <p>A <em>profile</em> is a named logical grouping that may be activated * programmatically via {@link ConfigurableEnvironment#setActiveProfiles} or declaratively * by setting the {@link AbstractEnvironment#ACTIVE_PROFILES_PROPERTY_NAME * spring.profiles.active} property as a JVM system property, as an * environment variable, or as a Servlet context parameter in {@code web.xml} * for web applications. Profiles may also be activated declaratively in * integration tests via the {@code @ActiveProfiles} annotation. * * <p>The {@code @Profile} annotation may be used in any of the following ways: * <ul> * <li>as a type-level annotation on any class directly or indirectly annotated with * {@code @Component}, including {@link Configuration @Configuration} classes</li> * <li>as a meta-annotation, for the purpose of composing custom stereotype annotations</li> * <li>as a method-level annotation on any {@link Bean @Bean} method</li> * </ul> * * <p>If a {@code @Configuration} class is marked with {@code @Profile}, all of the * {@code @Bean} methods and {@link Import @Import} annotations associated with that class * will be bypassed unless one or more of the specified profiles are active. A profile * string may contain a simple profile name (for example {@code "p1"}) or a profile * expression. A profile expression allows for more complicated profile logic to be * expressed, for example {@code "p1 & p2"}. See {@link Profiles#of(String...)} for more * details about supported formats. * * <p>This is analogous to the behavior in Spring XML: if the {@code profile} attribute of * the {@code beans} element is supplied e.g., {@code <beans profile="p1,p2">}, the * {@code beans} element will not be parsed unless at least profile 'p1' or 'p2' has been * activated. Likewise, if a {@code @Component} or {@code @Configuration} class is marked * with {@code @Profile({"p1", "p2"})}, that class will not be registered or processed unless * at least profile 'p1' or 'p2' has been activated. * * <p>If a given profile is prefixed with the NOT operator ({@code !}), the annotated * component will be registered if the profile is <em>not</em> active — for example, * given {@code @Profile({"p1", "!p2"})}, registration will occur if profile 'p1' is active * or if profile 'p2' is <em>not</em> active. * * <p>If the {@code @Profile} annotation is omitted, registration will occur regardless * of which (if any) profiles are active. * * <p><b>NOTE:</b> With {@code @Profile} on {@code @Bean} methods, a special scenario may * apply: In the case of overloaded {@code @Bean} methods of the same Java method name * (analogous to constructor overloading), an {@code @Profile} condition needs to be * consistently declared on all overloaded methods. If the conditions are inconsistent, * only the condition on the first declaration among the overloaded methods will matter. * {@code @Profile} can therefore not be used to select an overloaded method with a * particular argument signature over another; resolution between all factory methods * for the same bean follows Spring's constructor resolution algorithm at creation time. * <b>Use distinct Java method names pointing to the same {@link Bean#name bean name} * if you'd like to define alternative beans with different profile conditions</b>; * see {@code ProfileDatabaseConfig} in {@link Configuration @Configuration}'s javadoc. * * <p>When defining Spring beans via XML, the {@code "profile"} attribute of the * {@code <beans>} element may be used. See the documentation in the * {@code spring-beans} XSD (version 3.1 or greater) for details. * * @author Chris Beams * @author Phillip Webb * @author Sam Brannen * @since 3.1 * @see ConfigurableEnvironment#setActiveProfiles * @see ConfigurableEnvironment#setDefaultProfiles * @see AbstractEnvironment#ACTIVE_PROFILES_PROPERTY_NAME * @see AbstractEnvironment#DEFAULT_PROFILES_PROPERTY_NAME * @see Conditional * @see org.springframework.test.context.ActiveProfiles */ @Target({ ElementType.TYPE, ElementType.METHOD }) @Retention(RetentionPolicy.RUNTIME) @Documented @Conditional(ProfileCondition.class) public @interface Profile { /** * The set of profiles for which the annotated component should be registered. */ String[] value(); }