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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.*;

/**
 * REST has-form-data annotation.
 *
 * Identifies whether or not an HTTP request has the specified multipart form POST parameter.
 *
 * 
 * Can be used in the following locations:
 * 

 * 	Arguments and argument-types of server-side @RestOp-annotated methods.
 * 
 * 
 * 	This annotation can be used to detect the existence of a parameter when it's not set to a particular value.
 * 
 *
 * Example:
 * 
 * 	@RestPost
 * 	public void doPost(@HasFormData("p1") boolean p1) {...}
 * 
 * 
 * 	This is functionally equivalent to the following code:
 * 
 * 
 * 	@RestPost
 * 	public void doPost(RestRequest req) {
 * 		boolean p1 = req.getFormParam("p1").isPresent();
 * 		...
 * 	}
 * 
 * 
 * 	The parameter type must be either boolean or {@link java.lang.Boolean}.
 * 
 * 
 * 	The following table shows the behavioral differences between @HasFormData and @FormData:
 * 
 * 
 * 	
 * 		
 * 		
 * 		
 * 	
 * 	
 * 		
 * 		
 * 		
 * 	
 * 	
 * 		
 * 		
 * 		
 * 	
 * 	
 * 		
 * 		
 * 		
 * 	
 * 	
 * 		
 * 		
 * 		
 * 	
 * Body content @HasFormData("a") @FormData("a")
a=foo true "foo"
a= true ""
a true null
b=foo false null
 *
 * Important note concerning FORM posts
 * 
 * 	This annotation should not be combined with the {@link Content @Content} annotation or {@code RestRequest.getContent()} method
 * 	for application/x-www-form-urlencoded POST posts, since it will trigger the underlying servlet API to
 * 	parse the body content as key-value pairs, resulting in empty content.
 * 
 * 
 * 	The {@link HasQuery @HasQuery} annotation can be used to check for the existing of a URL parameter in the URL string
 * 	without triggering the servlet to drain the body content.
 * 
 *
 * 
 * 
See Also:


 * 
 */
@Documented
@Target({PARAMETER})
@Retention(RUNTIME)
@Inherited
public @interface HasFormData {

	/**
	 * FORM parameter name.
	 *
	 * Required. The name of the parameter. Parameter names are case sensitive.
	 *
	 * Notes:

	 * 	
	 * 		The format is plain-text.
	 * 
	 *
	 * @return The annotation value.
	 */
	String name() default "";

	/**
	 * A synonym for {@link #name()}.
	 *
	 * 
	 * Allows you to use shortened notation if you're only specifying the name.
	 *
	 * 

	 * The following are completely equivalent ways of defining the existence of a form post entry:
	 * 

	 * 	public Order placeOrder(@HasFormData(name="petId") boolean hasPetId) {...}
	 * 
	 * 
	 * 	public Order placeOrder(@HasFormData("petId") boolean hasPetId) {...}
	 * 
	 *
	 * @return The annotation value.
	 */
	String value() default "";
}