fasthashmap.java

iBATIS似乎已远离众说纷纭的OR框架之列

                return (map.isEmpty());
            }
        }

    }


    /**
     * Return a set view of the keys contained in this map.
     */
    public Set keySet() {
        return new KeySet();
    }


    /**
     * Associate the specified value with the specified key in this map.
     * If the map previously contained a mapping for this key, the old
     * value is replaced and returned.
     *
     * @param key The key with which the value is to be associated
     * @param value The value to be associated with this key
     */
    public Object put(Object key, Object value) {

        if (fast) {
            synchronized (this) {
                HashMap temp = (HashMap) map.clone();
                Object result = temp.put(key, value);
                map = temp;
                return (result);
            }
        } else {
            synchronized (map) {
                return (map.put(key, value));
            }
        }

    }


    /**
     * Copy all of the mappings from the specified map to this one, replacing
     * any mappings with the same keys.
     *
     * @param in Map whose mappings are to be copied
     */
    public void putAll(Map in) {

        if (fast) {
            synchronized (this) {
                HashMap temp = (HashMap) map.clone();
                temp.putAll(in);
                map = temp;
            }
        } else {
            synchronized (map) {
                map.putAll(in);
            }
        }

    }


    /**
     * Remove any mapping for this key, and return any previously
     * mapped value.
     *
     * @param key Key whose mapping is to be removed
     */
    public Object remove(Object key) {

        if (fast) {
            synchronized (this) {
                HashMap temp = (HashMap) map.clone();
                Object result = temp.remove(key);
                map = temp;
                return (result);
            }
        } else {
            synchronized (map) {
                return (map.remove(key));
            }
        }

    }


    /**
     * Return the number of key-value mappings in this map.
     */
    public int size() {

        if (fast) {
            return (map.size());
        } else {
            synchronized (map) {
                return (map.size());
            }
        }

    }


    /**
     * Return a collection view of the values contained in this map.
     */
    public Collection values() {
        return new Values();
    }


    private abstract class CollectionView implements Collection {

        public CollectionView() {
        }

        protected abstract Collection get(Map map);
        protected abstract Object iteratorNext(Map.Entry entry);


        public void clear() {
            if (fast) {
                synchronized (FastHashMap.this) {
                    HashMap temp = (HashMap) map.clone();
                    get(temp).clear();
                    map = temp;
                }
            } else {
                synchronized (map) {
                    get(map).clear();
                }
            }
        }

        public boolean remove(Object o) {
            if (fast) {
                synchronized (FastHashMap.this) {
                    HashMap temp = (HashMap) map.clone();
                    boolean r = get(temp).remove(o);
                    map = temp;
                    return r;
                }
            } else {
                synchronized (map) {
                    return get(map).remove(o);
                }
            }
        }

        public boolean removeAll(Collection o) {
            if (fast) {
                synchronized (FastHashMap.this) {
                    HashMap temp = (HashMap) map.clone();
                    boolean r = get(temp).removeAll(o);
                    map = temp;
                    return r;
                }
            } else {
                synchronized (map) {
                    return get(map).removeAll(o);
                }
            }
        }

        public boolean retainAll(Collection o) {
            if (fast) {
                synchronized (FastHashMap.this) {
                    HashMap temp = (HashMap) map.clone();
                    boolean r = get(temp).retainAll(o);
                    map = temp;
                    return r;
                }
            } else {
                synchronized (map) {
                    return get(map).retainAll(o);
                }
            }
        }

        public int size() {
            if (fast) {
                return get(map).size();
            } else {
                synchronized (map) {
                    return get(map).size();
                }
            }
        }


        public boolean isEmpty() {
            if (fast) {
                return get(map).isEmpty();
            } else {
                synchronized (map) {
                    return get(map).isEmpty();
                }
            }
        }

        public boolean contains(Object o) {
            if (fast) {
                return get(map).contains(o);
            } else {
                synchronized (map) {
                    return get(map).contains(o);
                }
            }
        }

        public boolean containsAll(Collection o) {
            if (fast) {
                return get(map).containsAll(o);
            } else {
                synchronized (map) {
                    return get(map).containsAll(o);
                }
            }
        }

        public Object[] toArray(Object[] o) {
            if (fast) {
                return get(map).toArray(o);
            } else {
                synchronized (map) {
                    return get(map).toArray(o);
                }
            }
        }

        public Object[] toArray() {
            if (fast) {
                return get(map).toArray();
            } else {
                synchronized (map) {
                    return get(map).toArray();
                }
            }
        }


        public boolean equals(Object o) {
            if (o == this) return true;
            if (fast) {
                return get(map).equals(o);
            } else {
                synchronized (map) {
                    return get(map).equals(o);
                }
            }
        }

        public int hashCode() {
            if (fast) {
                return get(map).hashCode();
            } else {
                synchronized (map) {
                    return get(map).hashCode();
                }
            }
        }

        public boolean add(Object o) {
            throw new UnsupportedOperationException();
        }

        public boolean addAll(Collection c) {
            throw new UnsupportedOperationException();
        }

        public Iterator iterator() {
            return new CollectionViewIterator();
        }

        private class CollectionViewIterator implements Iterator {

            private Map expected;
            private Map.Entry lastReturned = null;
            private Iterator iterator;

            public CollectionViewIterator() {
                this.expected = map;
                this.iterator = expected.entrySet().iterator();
            }
 
            public boolean hasNext() {
                if (expected != map) {
                    throw new ConcurrentModificationException();
                }
                return iterator.hasNext();
            }

            public Object next() {
                if (expected != map) {
                    throw new ConcurrentModificationException();
                }
                lastReturned = (Map.Entry)iterator.next();
                return iteratorNext(lastReturned);
            }

            public void remove() {
                if (lastReturned == null) {
                    throw new IllegalStateException();
                }
                if (fast) {
                    synchronized (FastHashMap.this) {
                        if (expected != map) {
                            throw new ConcurrentModificationException();
                        }
                        FastHashMap.this.remove(lastReturned.getKey());
                        lastReturned = null;
                        expected = map;
                    }
                } else {
                    iterator.remove();
                    lastReturned = null;
                }
            }
        }
   }


   private class KeySet extends CollectionView implements Set {

       protected Collection get(Map map) {
           return map.keySet();
       }

       protected Object iteratorNext(Map.Entry entry) {
           return entry.getKey();
       }       

   }


   private class Values extends CollectionView {

       protected Collection get(Map map) {
           return map.values();
       }

       protected Object iteratorNext(Map.Entry entry) {
           return entry.getValue();
       }
   }


   private class EntrySet extends CollectionView implements Set {

       protected Collection get(Map map) {
           return map.entrySet();
       }


       protected Object iteratorNext(Map.Entry entry) {
           return entry;
       }

   }

}