### Registering Extensions in plugin.xml

Source: https://github.com/willuhn/jameica/blob/master/src/de/willuhn/jameica/gui/extension/package.html

Define extensions in the plugin manifest to associate a Java class with specific extendable component IDs.

```xml
<plugin>
  [...]
  
  <menu>
    <item id="id.menu.erweiterbar" name=...../>
  </menu>

  <navigation>
    <item name=...../>
  </navigation>

  <services>
    <service name=...../>
  </services>
  
  
  <extensions>
    <extension class="name.der.java.Klasse" extends="id.menu.erweiterbar,id.extendable2,..." />
  </extensions>
  
</plugin>
```

--------------------------------

### Implementing Extendable Components

Source: https://github.com/willuhn/jameica/blob/master/src/de/willuhn/jameica/gui/extension/package.html

Implement the Extendable interface and call ExtensionRegistry.extend(this) within the constructor to allow the component to be extended by registered plugins.

```java
public class AddressList extends ContextMenu implements Extendable
{
  public AddressList()
  {
    addItem(new CheckedContextMenuItem(i18n.tr("ffnen"),new AddressNew()));
    addItem(ContextMenuItem.SEPARATOR);
    addItem(new CheckedContextMenuItem(i18n.tr("Lschen..."), new AddressDelete()));
    addItem(ContextMenuItem.SEPARATOR);
    addItem(new ContextMenuItem(i18n.tr("Neue Adresse..."), new AddressNeu()));
    
    // Uebergabe an Extension-Registry zur eventuellen Erweiterung um weitere Eintraege.
    ExtensionRegistry.extend(this);
  }
}
```

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