fasthashmap.java

这是一个有关common beanutils 的源码

            synchronized (map) {
                if (mo.size() != map.size()) {
                    return (false);
                }
                Iterator i = map.entrySet().iterator();
                while (i.hasNext()) {
                    Map.Entry e = (Map.Entry) i.next();
                    Object key = e.getKey();
                    Object value = e.getValue();
                    if (value == null) {
                        if (!(mo.get(key) == null && mo.containsKey(key))) {
                            return (false);
                        }
                    } else {
                        if (!value.equals(mo.get(key))) {
                            return (false);
                        }
                    }
                }
                return (true);
            }
        }
    }

    /**
     * Return the hash code value for this map.  This implementation uses
     * exactly the code that is used to define the list hash function in the
     * documentation for the <code>Map.hashCode</code> method.
     * 
     * @return suitable integer hash code
     */
    public int hashCode() {
        if (fast) {
            int h = 0;
            Iterator i = map.entrySet().iterator();
            while (i.hasNext()) {
                h += i.next().hashCode();
            }
            return (h);
        } else {
            synchronized (map) {
                int h = 0;
                Iterator i = map.entrySet().iterator();
                while (i.hasNext()) {
                    h += i.next().hashCode();
                }
                return (h);
            }
        }
    }

    /**
     * Return a shallow copy of this <code>FastHashMap</code> instance.
     * The keys and values themselves are not copied.
     * 
     * @return a clone of this map
     */
    public Object clone() {
        FastHashMap results = null;
        if (fast) {
            results = new FastHashMap(map);
        } else {
            synchronized (map) {
                results = new FastHashMap(map);
            }
        }
        results.setFast(getFast());
        return (results);
    }

    // Map views
    // ----------------------------------------------------------------------
    
    /**
     * Return a collection view of the mappings contained in this map.  Each
     * element in the returned collection is a <code>Map.Entry</code>.
     * @return the set of map Map entries
     */
    public Set entrySet() {
        return new EntrySet();
    }

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

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

    // Map view inner classes
    // ----------------------------------------------------------------------

    /**
     * Abstract collection implementation shared by keySet(), values() and entrySet().
     */
    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) {
                    map = new HashMap();
                }
            } 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;
                }
            }
        }
    }

    /**
     * Set implementation over the keys of the FastHashMap
     */
    private class KeySet extends CollectionView implements Set {
    
        protected Collection get(Map map) {
            return map.keySet();
        }
    
        protected Object iteratorNext(Map.Entry entry) {
            return entry.getKey();
        }
    
    }
    
    /**
     * Collection implementation over the values of the FastHashMap
     */
    private class Values extends CollectionView {
    
        protected Collection get(Map map) {
            return map.values();
        }
    
        protected Object iteratorNext(Map.Entry entry) {
            return entry.getValue();
        }
    }
    
    /**
     * Set implementation over the entries of the FastHashMap
     */
    private class EntrySet extends CollectionView implements Set {
    
        protected Collection get(Map map) {
            return map.entrySet();
        }
    
        protected Object iteratorNext(Map.Entry entry) {
            return entry;
        }
    
    }

}