package org.webslinger.lang;

 import java.lang.ref.Reference;

 public abstract class ReferenceWrapper<T> implements ObjectWrapper<T> {

     private final ObjectWrapper<T> fetcher;

     private Reference<T> ref;

     public ReferenceWrapper(ObjectWrapper<T> fetcher) throws Exception {

         this.fetcher = fetcher;

         ref = newReference(fetcher.getObject());

     }

     public T getObject() throws Exception {

         T value = ref.get();

         if (value != null) return value;

         value = fetcher.getObject();

         ref = newReference(value);

         return value;

     }

     protected abstract Reference<T> newReference(T value);

 }