1 /*
   2  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 import java.util.AbstractCollection;
  24 import java.util.HashSet;
  25 import java.util.AbstractSet;
  26 import java.util.ArrayList;
  27 import java.util.Collection;
  28 import java.util.Iterator;
  29 import java.util.function.Supplier;
  30 
  31 /**
  32  * @library
  33  *
  34  * A simple mutable collection implementation that provides only default
  35  * implementations of all methods. ie. none of the Collection interface default
  36  * methods have overridden implementations.
  37  *
  38  * @param <E> type of collection elements
  39  */
  40 public class ExtendsAbstractCollection<C extends Collection<E>, E> extends AbstractCollection<E> {
  41 
  42     protected final C coll;
  43 
  44     public ExtendsAbstractCollection() {
  45         this(() -> {return (C) new ArrayList<E>();});
  46     }
  47 
  48     public ExtendsAbstractCollection(Collection<E> source) {
  49         this();
  50         coll.addAll(source);
  51     }
  52 
  53     protected ExtendsAbstractCollection(Supplier<C> backer) {
  54         this.coll = backer.get();
  55     }
  56 
  57     public boolean add(E element) {
  58         return coll.add(element);
  59     }
  60 
  61     public boolean remove(Object element) {
  62         return coll.remove(element);
  63     }
  64 
  65     public Iterator<E> iterator() {
  66         return new Iterator<E>() {
  67             Iterator<E> source = coll.iterator();
  68 
  69             public boolean hasNext() {
  70                 return source.hasNext();
  71             }
  72 
  73             public E next() {
  74                 return source.next();
  75             }
  76 
  77             public void remove() {
  78                 source.remove();
  79             }
  80         };
  81     }
  82 
  83     public int size() {
  84         return coll.size();
  85     }
  86 }