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--- at-m42:lecture7 [2009/04/13 15:53] – eechris
+++ at-m42:lecture7 [2011/01/14 12:45] (current) – external edit 127.0.0.1
@@ Line 749: / Line 749: @@
 }
-abstract class AbstractItem implements Portable { ...  }
+abstract class AbstractItem implements Portable { ... }
 class WeightyItem extends AbstractItem { ... }
-}
 class MagicalItem extends AbstractItem { ... }
 </code>
+Full listing for [[http://www.cpjobling.org.uk/~eechris/at-m42/Examples/lecture07/example15.groovy|Example 15]] is given in the notes.
+----
+The implementation for this is give in Example 15, where ''Portable'' is introduced as a an interface class. An interface declares, but does not define, one or more abstract methods. The abstract class ''AbstractItem'' conforms to the protocol since it //implements// the ''Portable// interface. Notice that ''AbstractItem'' offers a simple implementation for the ''canCarry'' method. We must explicitly redefine it in the ''WeightyItem'' and ''MigicalItem'' classes (note we use the superclass definitions in both!).
 <code groovy 1 | Example 15: The interface calls (at-m42/Examples/lecture07/example15.groovy)>