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

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

import java.lang.annotation.*;

import org.apache.juneau.swap.*;

/**
 * Associates {@link ObjectSwap} and {@link Surrogate} classes with POJOs and bean properties.
 *
 * 
 * Can be used in the following locations:
 * 

 * 	Classes.
 * 	
Bean getters/setters/fields.
 * 	
@Rest-annotated classes and @RestOp-annotated methods when an {@link #on()} value is specified.
 * 

 * See Also:

 * 	@Swap Annotation

 * 
 */
@Documented
@Target({TYPE,ANNOTATION_TYPE,FIELD,METHOD})
@Retention(RUNTIME)
@Inherited
@Repeatable(SwapAnnotation.Array.class)
@ContextApply(SwapAnnotation.Applier.class)
public @interface Swap {

	/**
	 * The {@link ObjectSwap} and {@link Surrogate} class.
	 *
	 * 
	 * A synonym for {@link #value()}.
	 *
	 * @return The annotation value.
	 */
	Class impl() default void.class;

	/**
	 * Identifies the media types that this swap is applicable for.
	 *
	 * 

	 * In the following example, the swap is only invoked by the JSON serializer:
	 *
	 * 

	 * 	@Swap(impl=ToStringSwap.class, mediaTypes="*/json")
	 * 	public class MyBean { ... }
	 *
	 * 	public class ToStringSwap extends ObjectSwap<Object,String> {
	 * 			public String swap(BeanSession session, Object value) throws Exception {
	 * 				return value.toString();
	 * 			}
	 * 		}
	 * 
	 *
	 * See Also:

	 * 	Per-media-type Swaps
	 * 
	 *
	 * @return The annotation value.
	 */
	String[] mediaTypes() default {};

	/**
	 * Dynamically apply this annotation to the specified classes/methods/fields.
	 *
	 * 
	 * Used in conjunction with {@link org.apache.juneau.BeanContext.Builder#applyAnnotations(Class...)} to dynamically apply an annotation to an existing class.
	 * It is ignored when the annotation is applied directly to classes.
	 *
	 * 
Valid patterns:
	 * 
	 *  Classes:
	 * 		
	 * 			Fully qualified:
	 * 				
	 * 					"com.foo.MyClass"
	 * 				
	 * 			
Fully qualified inner class:
	 * 				
	 * 					"com.foo.MyClass$Inner1$Inner2"
	 * 				
	 * 			
Simple:
	 * 				
	 * 					"MyClass"
	 * 				
	 * 			
Simple inner:
	 * 				
	 * 					"MyClass$Inner1$Inner2"
	 * 					
"Inner1$Inner2"
	 * 					
"Inner2"
	 * 				
	 * 		
	 * 	
Methods:
	 * 		
	 * 			Fully qualified with args:
	 * 				
	 * 					"com.foo.MyClass.myMethod(String,int)"
	 * 					
"com.foo.MyClass.myMethod(java.lang.String,int)"
	 * 					
"com.foo.MyClass.myMethod()"
	 * 				
	 * 			
Fully qualified:
	 * 				
	 * 					"com.foo.MyClass.myMethod"
	 * 				
	 * 			
Simple with args:
	 * 				
	 * 					"MyClass.myMethod(String,int)"
	 * 					
"MyClass.myMethod(java.lang.String,int)"
	 * 					
"MyClass.myMethod()"
	 * 				
	 * 			
Simple:
	 * 				
	 * 					"MyClass.myMethod"
	 * 				
	 * 			
Simple inner class:
	 * 				
	 * 					"MyClass$Inner1$Inner2.myMethod"
	 * 					
"Inner1$Inner2.myMethod"
	 * 					
"Inner2.myMethod"
	 * 				
	 * 		
	 * 	
Fields:
	 * 		
	 * 			Fully qualified:
	 * 				
	 * 					"com.foo.MyClass.myField"
	 * 				
	 * 			
Simple:
	 * 				
	 * 					"MyClass.myField"
	 * 				
	 * 			
Simple inner class:
	 * 				
	 * 					"MyClass$Inner1$Inner2.myField"
	 * 					
"Inner1$Inner2.myField"
	 * 					
"Inner2.myField"
	 * 				
	 * 		
	 * 	
A comma-delimited list of anything on this list.
	 * 
	 *
	 * 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 {};

	/**
	 * Identifies a template string along with this swap.
	 *
	 * 
	 * Template strings are arbitrary strings associated with swaps that help provide additional context information
	 * for the swap class.
	 * They're called 'templates' because their primary purpose is for providing template names, such as Apache FreeMarker
	 * template names.
	 *
	 * 

	 * The following is an example of a templated swap class used to serialize POJOs to HTML using FreeMarker:
	 *
	 * 

	 * 	// Our templated swap class.
	 * 	public class FreeMarkerSwap extends ObjectSwap<Object,Reader> {
	 *
	 * 		public MediaType[] forMediaTypes() {
	 * 			return MediaType.forStrings("*/html");
	 * 		}
	 *
	 * 		public Reader swap(BeanSession session, Object value, String template) throws Exception {
	 * 			return getFreeMarkerReader(template, value);  // Some method that creates raw HTML.
	 * 		}
	 * 	}
	 * 
	 * 
	 * 	@Swap(impl=FreeMarkerSwap.class, template="MyPojo.div.ftl")
	 * 	public class MyPojo {}
	 * 
	 *
	 * See Also:

	 * 	Templated Swaps
	 * 
	 *
	 * @return The annotation value.
	 */
	String template() default "";

	/**
	 * The {@link ObjectSwap} and {@link Surrogate} class.
	 *
	 * 
	 * A synonym for {@link #impl()}.
	 *
	 * @return The annotation value.
	 */
	Class value() default void.class;
}