package org.webslinger.modules;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashMap;

 import java.util.concurrent.atomic.AtomicInteger;

 import java.lang.ref.SoftReference;

 import org.apache.commons.vfs.FileObject;

 public abstract class AbstractWorkAreaFactory<T extends WorkArea> implements WorkAreaFactory<T> {

     protected final HashMap<String, SoftReference<T>> workAreas = new HashMap<String, SoftReference<T>>();

     protected AtomicInteger tempCount = new AtomicInteger();

     protected final FileObject work;

     protected AbstractWorkAreaFactory(FileObject work) throws IOException {

         this.work = work;

         work.resolveFile("named").createFolder();

         work.resolveFile("temp").createFolder();

     }

     public T create() throws IOException {

         return createWorkArea(null, "temp/" + tempCount.incrementAndGet());

     }

     protected abstract T createWorkArea(String name, String location) throws IOException;

     public T join(String name) throws IOException {

         SoftReference<T> ref = workAreas.get(name);

         if (ref != null) {

             T workArea = ref.get();

             if (workArea != null) return workArea;

         }

         T workArea = createWorkArea(name, "named/" + name);

         workAreas.put(name, new SoftReference<T>(workArea));

         return workArea;

     }

     public Collection<? extends T> getWorkAreas() throws IOException {

         ArrayList<T> workAreas = new ArrayList<T>();

         FileObject[] children = work.resolveFile("named").getChildren();

         if (children == null) return workAreas;

         for (FileObject child: children) {

             workAreas.add(join(child.getName().getBaseName()));

         }

         return workAreas;

     }

 }