/*
 * Copyright 2015-2020 the original author or authors.
 *
 * All rights reserved. This program and the accompanying materials are
 * made available under the terms of the Eclipse Public License v2.0 which
 * accompanies this distribution and is available at
 *
 * https://www.eclipse.org/legal/epl-v20.html
 */

package org.junit.jupiter.api.condition;

import static org.apiguardian.api.API.Status.STABLE;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.apiguardian.api.API;
import org.junit.jupiter.api.extension.ExtendWith;

/**
 * {@code @EnabledIfEnvironmentVariable} is used to signal that the annotated test
 * class or test method is only <em>enabled</em> if the value of the specified
 * {@linkplain #named environment variable} matches the specified
 * {@linkplain #matches regular expression}.
 *
 * <p>When declared at the class level, the result will apply to all test methods
 * within that class as well.
 *
 * <p>If a test method is disabled via this annotation, that does not prevent
 * the test class from being instantiated. Rather, it prevents the execution of
 * the test method and method-level lifecycle callbacks such as {@code @BeforeEach}
 * methods, {@code @AfterEach} methods, and corresponding extension APIs.
 *
 * <p>If the specified environment variable is undefined, the annotated class or
 * method will be disabled.
 *
 * <p>This annotation may be used as a meta-annotation in order to create a
 * custom <em>composed annotation</em> that inherits the semantics of this
 * annotation.
 *
 * <p>As of JUnit Jupiter 5.6, this annotation is a {@linkplain Repeatable
 * repeatable} annotation. Consequently, this annotation may be declared multiple
 * times on an {@link java.lang.reflect.AnnotatedElement AnnotatedElement} (i.e.,
 * test interface, test class, or test method). Specifically, this annotation will
 * be found if it is directly present, indirectly present, or meta-present on a
 * given element.
 *
 * @since 5.1
 * @see org.junit.jupiter.api.condition.DisabledIfEnvironmentVariable
 * @see org.junit.jupiter.api.condition.EnabledIfSystemProperty
 * @see org.junit.jupiter.api.condition.DisabledIfSystemProperty
 * @see org.junit.jupiter.api.condition.EnabledOnJre
 * @see org.junit.jupiter.api.condition.DisabledOnJre
 * @see org.junit.jupiter.api.condition.EnabledForJreRange
 * @see org.junit.jupiter.api.condition.DisabledForJreRange
 * @see org.junit.jupiter.api.condition.EnabledOnOs
 * @see org.junit.jupiter.api.condition.DisabledOnOs
 * @see org.junit.jupiter.api.Disabled
 */
@Target({ ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(EnabledIfEnvironmentVariables.class)
@ExtendWith(EnabledIfEnvironmentVariableCondition.class)
@API(status = STABLE, since = "5.1")
public @interface EnabledIfEnvironmentVariable {

	/**
	 * The name of the environment variable to retrieve.
	 *
	 * @return the environment variable name; never <em>blank</em>
	 * @see System#getenv(String)
	 */
	String named();

	/**
	 * A regular expression that will be used to match against the retrieved
	 * value of the {@link #named} environment variable.
	 *
	 * @return the regular expression; never <em>blank</em>
	 * @see String#matches(String)
	 * @see java.util.regex.Pattern
	 */
	String matches();

}
