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// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
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package org.apache.juneau.http.annotation;

import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;

import java.lang.annotation.*;

import org.apache.juneau.annotation.*;
import org.apache.juneau.json.*;

/**
 * REST request body annotation.
 *
 * 
 * Identifies a POJO to be used as the body of an HTTP request.
 *
 * 

 * Can be used in the following locations:
 * 

 * 	Arguments and argument-types of server-side @RestOp-annotated methods.
 * 	
Arguments and argument-types of client-side @RemoteOp-annotated interfaces.
 * 	
Methods and return types of server-side and client-side @Request-annotated interfaces.
 * 
 *
 * Arguments and argument-types of server-side @RestOp-annotated methods
 *
 * 
 * On server-side REST, this annotation can be applied to method parameters or parameter classes to identify them as the body of an HTTP request.
 *
 * 
Examples:
 * 
 * 	// Used on parameter
 * 	@RestPost("/pets")
 * 	public void addPet(@Content Pet pet) {...}
 * 
 * 
 * 	// Used on class
 * 	@RestPost("/pets")
 * 	public void addPet(Pet pet) {...}
 *
 * 	@Content
 * 	public class Pet {...}
 * 
 *
 * 
 * This is functionally equivalent to the following code...
 * 

 * 	@RestPost("/pets")
 * 	public void addPet(RestRequest req) {
 * 		Pet pet = req.getContent().as(Pet.class);
 * 		...
 * 	}
 * 
 *
 * Arguments and argument-types of client-side @RemoteResource-annotated interfaces
 *
 * See Also:

 * 	@Content
 * 
 *
 * Methods and return types of server-side and client-side @Request-annotated interfaces
 *
 * See Also:

 * 	@Request
 * 
 *
 * Notes:

 * 	
 * 		Annotation parameter values will be aggregated when used on POJO parent and child classes.
 * 		
Values on child classes override values on parent classes.
 * 	

 * 		Annotation parameter values will be aggregated when used on both POJOs and REST methods.
 * 		
Values on methods override values on POJO classes.
 * 	

 * 		If using this annotation on a Spring bean, note that you are likely to encounter issues when using on parameterized
 * 		types such as List<MyBean>.  This is due to the fact that Spring uses CGLIB to recompile classes
 * 		at runtime, and CGLIB was written before generics were introduced into Java and is a virtually-unsupported library.
 * 		Therefore, parameterized types will often be stripped from class definitions and replaced with unparameterized types
 *		(e.g. List).  Under these circumstances, you are likely to get ClassCastExceptions
 *		when trying to access generalized JsonMaps as beans.  The best solution to this issue is to either
 *		specify the parameter as a bean array (e.g. MyBean[]) or declare the method as final so that CGLIB
 *		will not try to recompile it.
 * 
 *
 * See Also:


 * 
 */
@Documented
@Target({PARAMETER,METHOD,TYPE})
@Retention(RUNTIME)
@Inherited
@Repeatable(ContentAnnotation.Array.class)
@ContextApply(ContentAnnotation.Applier.class)
public @interface Content {

	/**
	 * Dynamically apply this annotation to the specified classes.
	 *
	 * See Also:

	 * 	Dynamically Applied Annotations
	 * 
	 *
	 * @return The annotation value.
	 */
	String[] on() default {};

	/**
	 * Dynamically apply this annotation to the specified classes.
	 *
	 * 
	 * Identical to {@link #on()} except allows you to specify class objects instead of a strings.
	 *
	 * 
See Also:

	 * 	Dynamically Applied Annotations
	 * 
	 *
	 * @return The annotation value.
	 */
	Class[] onClass() default {};

	/**
	 * schema field of the Swagger Parameter Object.
	 *
	 * 
	 * The schema defining the type used for parameter.
	 *
	 * 

	 * This is a required attribute per the swagger definition.
	 * However, if not explicitly specified, the value will be auto-generated using {@link JsonSchemaSerializer}.
	 *
	 * 

	 * The {@link Schema @Schema} annotation can also be used standalone on the parameter or type.
	 * Values specified on this field override values specified on the type, and values specified on child types override values
	 * specified on parent types.
	 *
	 * 
Used for:
	 * 
	 * 	
	 * 		Server-side schema-based parsing and parsing validation.
	 * 	

	 * 		Server-side generated Swagger documentation.
	 * 	

	 * 		Client-side schema-based serializing and serializing validation.
	 * 
	 *
	 * @return The annotation value.
	 */
	Schema schema() default @Schema;
}