package org.trails.descriptor;

 import java.util.Map;

 /**

  * Implementation of the "Extension Object Pattern (Erich Gamma)"

  * Participant: Subject.

  * It declares the interface to query whether an object has a particular extension.

  */

 public interface IExtensible

 {

         public boolean supportsExtension(String key);

         public void removeExtension(String key);

         public void addExtension(String key, IDescriptorExtension extension);

         public boolean supportsExtension(Class extensionType);

         public void removeExtension(Class extensionType);

         public void addExtension(Class extensionType, IDescriptorExtension extension);

         public IDescriptorExtension getExtension(String key);

         public <E extends IDescriptorExtension> E getExtension(Class<E> extensionType);

     Map<String, IDescriptorExtension> getExtensions();

 }