Introduce composed annotations for web scopes

This commit introduces the following common composed annotations for
web scopes.

- @requestScope
- @SessionScope
- @ApplicationScope

Issue: SPR-13993

spring-web/src/main/java/org/springframework/web/context/annotation/ApplicationScope.java

@@ -0,0 +1,66 @@
+/*
+ * 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.web.context.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+import org.springframework.core.annotation.AliasFor;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+import static org.springframework.web.context.WebApplicationContext.SCOPE_APPLICATION;
+
+/**
+ * {@code @ApplicationScope} is a specialization of {@link Scope @Scope} for a
+ * component whose lifecycle is bound to the current web application.
+ *
+ * <p>Specifically, {@code @ApplicationScope} is a <em>composed annotation</em> that
+ * acts as a shortcut for {@code @Scope("application")} with the default
+ * {@link #proxyMode} set to {@link ScopedProxyMode#TARGET_CLASS TARGET_CLASS}.
+ *
+ * <p>{@code @ApplicationScope} may be used as a meta-annotation to create custom
+ * composed annotations.
+ *
+ * @author Sam Brannen
+ * @since 4.3
+ * @see RequestScope
+ * @see SessionScope
+ * @see org.springframework.context.annotation.Scope
+ * @see org.springframework.web.context.WebApplicationContext#SCOPE_APPLICATION
+ * @see org.springframework.web.context.support.ServletContextScope
+ * @see org.springframework.stereotype.Component
+ * @see org.springframework.context.annotation.Bean
+ */
+@Scope(SCOPE_APPLICATION)
+@Target({ TYPE, METHOD })
+@Retention(RUNTIME)
+@Documented
+public @interface ApplicationScope {
+
+	/**
+	 * Alias for {@link Scope#proxyMode}.
+	 * <p>Defaults to {@link ScopedProxyMode#TARGET_CLASS}.
+	 */
+	@AliasFor(annotation = Scope.class)
+	ScopedProxyMode proxyMode() default ScopedProxyMode.TARGET_CLASS;
+
+}

spring-web/src/main/java/org/springframework/web/context/annotation/RequestScope.java

@@ -0,0 +1,66 @@
+/*
+ * 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.web.context.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+import org.springframework.core.annotation.AliasFor;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+import static org.springframework.web.context.WebApplicationContext.SCOPE_REQUEST;
+
+/**
+ * {@code @RequestScope} is a specialization of {@link Scope @Scope} for a
+ * component whose lifecycle is bound to the current web request.
+ *
+ * <p>Specifically, {@code @RequestScope} is a <em>composed annotation</em> that
+ * acts as a shortcut for {@code @Scope("request")} with the default
+ * {@link #proxyMode} set to {@link ScopedProxyMode#TARGET_CLASS TARGET_CLASS}.
+ *
+ * <p>{@code @RequestScope} may be used as a meta-annotation to create custom
+ * composed annotations.
+ *
+ * @author Sam Brannen
+ * @since 4.3
+ * @see SessionScope
+ * @see ApplicationScope
+ * @see org.springframework.context.annotation.Scope
+ * @see org.springframework.web.context.WebApplicationContext#SCOPE_REQUEST
+ * @see org.springframework.web.context.request.RequestScope
+ * @see org.springframework.stereotype.Component
+ * @see org.springframework.context.annotation.Bean
+ */
+@Scope(SCOPE_REQUEST)
+@Target({ TYPE, METHOD })
+@Retention(RUNTIME)
+@Documented
+public @interface RequestScope {
+
+	/**
+	 * Alias for {@link Scope#proxyMode}.
+	 * <p>Defaults to {@link ScopedProxyMode#TARGET_CLASS}.
+	 */
+	@AliasFor(annotation = Scope.class)
+	ScopedProxyMode proxyMode() default ScopedProxyMode.TARGET_CLASS;
+
+}

spring-web/src/main/java/org/springframework/web/context/annotation/SessionScope.java

@@ -0,0 +1,66 @@
+/*
+ * 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.web.context.annotation;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import org.springframework.context.annotation.Scope;
+import org.springframework.context.annotation.ScopedProxyMode;
+import org.springframework.core.annotation.AliasFor;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+import static org.springframework.web.context.WebApplicationContext.SCOPE_SESSION;
+
+/**
+ * {@code @SessionScope} is a specialization of {@link Scope @Scope} for a
+ * component whose lifecycle is bound to the current web session.
+ *
+ * <p>Specifically, {@code @SessionScope} is a <em>composed annotation</em> that
+ * acts as a shortcut for {@code @Scope("session")} with the default
+ * {@link #proxyMode} set to {@link ScopedProxyMode#TARGET_CLASS TARGET_CLASS}.
+ *
+ * <p>{@code @SessionScope} may be used as a meta-annotation to create custom
+ * composed annotations.
+ *
+ * @author Sam Brannen
+ * @since 4.3
+ * @see RequestScope
+ * @see ApplicationScope
+ * @see org.springframework.context.annotation.Scope
+ * @see org.springframework.web.context.WebApplicationContext#SCOPE_SESSION
+ * @see org.springframework.web.context.request.SessionScope
+ * @see org.springframework.stereotype.Component
+ * @see org.springframework.context.annotation.Bean
+ */
+@Scope(SCOPE_SESSION)
+@Target({ TYPE, METHOD })
+@Retention(RUNTIME)
+@Documented
+public @interface SessionScope {
+
+	/**
+	 * Alias for {@link Scope#proxyMode}.
+	 * <p>Defaults to {@link ScopedProxyMode#TARGET_CLASS}.
+	 */
+	@AliasFor(annotation = Scope.class)
+	ScopedProxyMode proxyMode() default ScopedProxyMode.TARGET_CLASS;
+
+}

src/asciidoc/whats-new.adoc

@@ -662,10 +662,11 @@ Spring 4.3 also improves the caching abstraction as follows:
 === Web Improvements
 
 * Built-in support for <<mvc-ann-requestmapping-head-options,HTTP HEAD and HTTP OPTIONS>>.
+* New `@RequestScope`, `@SessionScope`, and `@ApplicationScope` _composed annotations_ for web scopes.
 * New `@RestControllerAdvice` annotation with combined `@ControllerAdvice` with `@ResponseBody` semantics.
-* `@ResponseStatus` supported on the class level and inherited on all methods.
+* `@ResponseStatus` is now supported at the class level and inherited by all methods.
 * New `@SessionAttribute` annotation for access to session attributes (see <<mvc-ann-sessionattrib-global, example>>).
-* New `@RequestAttribute` annotation for access to session attributes (see <<mvc-ann-requestattrib, example>>).
+* New `@RequestAttribute` annotation for access to request attributes (see <<mvc-ann-requestattrib, example>>).
 * `@ModelAttribute` allows preventing data binding via `binding=false` attribute (see <<mvc-ann-modelattrib-method-args, reference>>).
 * `AsyncRestTemplate` supports request interception.