001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    
020    package org.crsh.util;
021    
022    import java.util.AbstractMap;
023    import java.util.AbstractSet;
024    import java.util.Iterator;
025    import java.util.Set;
026    
027    public abstract class SimpleMap<K, V> extends AbstractMap<K, V> {
028    
029      protected abstract Iterator<K> keys();
030    
031      @Override
032      public abstract V get(Object key);
033    
034      @Override
035      public final boolean containsKey(Object key) {
036        return get(key) != null;
037      }
038    
039      @Override
040      public final Set<Entry<K, V>> entrySet() {
041        return entries;
042      }
043    
044      private AbstractSet<Entry<K, V>> entries = new AbstractSet<Entry<K, V>>() {
045    
046        @Override
047        public Iterator<Entry<K, V>> iterator() {
048          final Iterator<K> names = keys();
049          return new Iterator<Entry<K, V>>() {
050            public boolean hasNext() {
051              return names.hasNext();
052            }
053    
054            public Entry<K, V> next() {
055              final K name = names.next();
056              return new Entry<K, V>() {
057                public K getKey() {
058                  return name;
059                }
060    
061                public V getValue() {
062                  return get(name);
063                }
064    
065                public V setValue(V value) {
066                  throw new UnsupportedOperationException();
067                }
068              };
069            }
070    
071            public void remove() {
072              throw new UnsupportedOperationException();
073            }
074          };
075        }
076    
077        @Override
078        public int size() {
079          int size = 0;
080          for (Iterator<K> names = keys();names.hasNext();) {
081            size++;
082            names.next();
083          }
084          return size;
085        }
086      };
087    }