/*
* Copyright 2002-2016 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
*
* http://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.core.env;
/**
* Interface representing the environment in which the current application is running.
* Models two key aspects of the application environment: <em>profiles</em> and
* <em>properties</em>. Methods related to property access are exposed via the
* {@link PropertyResolver} superinterface.
*
* <p>A <em>profile</em> is a named, logical group of bean definitions to be registered
* with the container only if the given profile is <em>active</em>. Beans may be assigned
* to a profile whether defined in XML or via annotations; see the spring-beans 3.1 schema
* or the {@link org.springframework.context.annotation.Profile @Profile} annotation for
* syntax details. The role of the {@code Environment} object with relation to profiles is
* in determining which profiles (if any) are currently {@linkplain #getActiveProfiles
* active}, and which profiles (if any) should be {@linkplain #getDefaultProfiles active
* by default}.
*
* <p><em>Properties</em> play an important role in almost all applications, and may
* originate from a variety of sources: properties files, JVM system properties, system
* environment variables, JNDI, servlet context parameters, ad-hoc Properties objects,
* Maps, and so on. The role of the environment object with relation to properties is to
* provide the user with a convenient service interface for configuring property sources
* and resolving properties from them.
*
* <p>Beans managed within an {@code ApplicationContext} may register to be {@link
* org.springframework.context.EnvironmentAware EnvironmentAware} or {@code @Inject} the
* {@code Environment} in order to query profile state or resolve properties directly.
*
* <p>In most cases, however, application-level beans should not need to interact with the
* {@code Environment} directly but instead may have to have {@code ${...}} property
* values replaced by a property placeholder configurer such as
* {@link org.springframework.context.support.PropertySourcesPlaceholderConfigurer
* PropertySourcesPlaceholderConfigurer}, which itself is {@code EnvironmentAware} and
* as of Spring 3.1 is registered by default when using
* {@code <context:property-placeholder/>}.
*
* <p>Configuration of the environment object must be done through the
* {@code ConfigurableEnvironment} interface, returned from all
* {@code AbstractApplicationContext} subclass {@code getEnvironment()} methods. See
* {@link ConfigurableEnvironment} Javadoc for usage examples demonstrating manipulation
* of property sources prior to application context {@code refresh()}.
*
* @author Chris Beams
* @since 3.1
* @see PropertyResolver
* @see EnvironmentCapable
* @see ConfigurableEnvironment
* @see AbstractEnvironment
* @see StandardEnvironment
* @see org.springframework.context.EnvironmentAware
* @see org.springframework.context.ConfigurableApplicationContext#getEnvironment
* @see org.springframework.context.ConfigurableApplicationContext#setEnvironment
* @see org.springframework.context.support.AbstractApplicationContext#createEnvironment
*/
public interface Environment extends PropertyResolver {
/**
* Return the set of profiles explicitly made active for this environment. Profiles
* are used for creating logical groupings of bean definitions to be registered
* conditionally, for example based on deployment environment. Profiles can be
* activated by setting {@linkplain AbstractEnvironment#ACTIVE_PROFILES_PROPERTY_NAME
* "spring.profiles.active"} as a system property or by calling
* {@link ConfigurableEnvironment#setActiveProfiles(String...)}.
* <p>If no profiles have explicitly been specified as active, then any
* {@linkplain #getDefaultProfiles() default profiles} will automatically be activated.
* @see #getDefaultProfiles
* @see ConfigurableEnvironment#setActiveProfiles
* @see AbstractEnvironment#ACTIVE_PROFILES_PROPERTY_NAME
*/
String[] getActiveProfiles();
/**
* Return the set of profiles to be active by default when no active profiles have
* been set explicitly.
* @see #getActiveProfiles
* @see ConfigurableEnvironment#setDefaultProfiles
* @see AbstractEnvironment#DEFAULT_PROFILES_PROPERTY_NAME
*/
String[] getDefaultProfiles();
/**
* Return whether one or more of the given profiles is active or, in the case of no
* explicit active profiles, whether one or more of the given profiles is included in
* the set of default profiles. If a profile begins with '!' the logic is inverted,
* i.e. the method will return true if the given profile is <em>not</em> active.
* For example, <pre class="code">env.acceptsProfiles("p1", "!p2")</pre> will
* return {@code true} if profile 'p1' is active or 'p2' is not active.
* @throws IllegalArgumentException if called with zero arguments
* or if any profile is {@code null}, empty or whitespace-only
* @see #getActiveProfiles
* @see #getDefaultProfiles
*/
boolean acceptsProfiles(String... profiles);
}