package org.webslinger.commons.vfs.util;

 import java.lang.reflect.Array;

 import java.util.Collection;

 import java.util.Set;

 import org.apache.commons.vfs.FileObject;

 public class FileAttributeKeySet<F extends FileObject, T> extends FileAttributeCollection<F, T> implements Set<T> {

     public FileAttributeKeySet(final FileAttributeMap<F> fam) {

         super(fam, new IteratorRemover() {

             public boolean remove(Object o) {

                 try {

                     F file = fam.getFile();

                     boolean result = fam.getResolver().attributeExists(file, (String) o);

                     fam.getResolver().removeAttribute(file, (String) o);

                     return result;

                 } catch (RuntimeException e) {

                     throw e;

                 } catch (Exception e) {

                     return false;

                 }

             }

         });

     }

     public boolean add(T o) {

         throw new UnsupportedOperationException("add");

     }

     public boolean addAll(Collection<? extends T> c) {

         throw new UnsupportedOperationException("addAll");

     }

     public boolean contains(Object o) {

         try {

             return resolver.attributeExists(getFile(), (String) o);

         } catch (Exception e) {

             return false;

         }

     }

     public <T> T[] toArray(T[] array) {

         try {

             String[] names = resolver.getAttributeNames(getFile());

             if (names.length <= array.length) {

                 System.arraycopy(names, 0, array, 0, names.length);

                 for (int i = names.length; i < array.length; i++) {

                     array[i] = null;

                 }

                 return array;

             }

             array = (T[]) Array.newInstance(array.getClass().getComponentType(), names.length);

             System.arraycopy(names, 0, array, 0, names.length);

             return array;

         } catch (RuntimeException e) {

             throw e;

         } catch (Exception e) {

             return null;

         }

     }

 }