fastarraylist.java

初级java程序员如果想要更深一步提高自己的实力

            }
        }

    }


    /**
     * Search for the first occurrence of the given argument, testing
     * for equality using the <code>equals()</code> method, and return
     * the corresponding index, or -1 if the object is not found.
     *
     * @param element The element to search for
     */
    public int indexOf(Object element) {

        if (fast) {
            return (list.indexOf(element));
        } else {
            synchronized (list) {
                return (list.indexOf(element));
            }
        }

    }


    /**
     * Test if this list has no elements.
     */
    public boolean isEmpty() {

        if (fast) {
            return (list.isEmpty());
        } else {
            synchronized (list) {
                return (list.isEmpty());
            }
        }

    }


    /**
     * Return an iterator over the elements in this list in proper sequence.
     * <p>
     * <b>Thread safety</b><br />
     * The iterator returned is thread-safe ONLY in FAST mode.
     * In slow mode there is no way to synchronize, or make the iterator thread-safe.
     * <p>
     * In fast mode iteration and modification may occur in parallel on different threads,
     * however there is a restriction. Modification must be EITHER via the Iterator
     * interface methods OR the List interface. If a mixture of modification
     * methods is used a ConcurrentModificationException is thrown from the iterator
     * modification method. If the List modification methods are used the changes are
     * NOT visible in the iterator (it shows the list contents at the time the iterator
     * was created).
     * 
     * @return the iterator
     */
    public Iterator iterator() {
        if (fast) {
            return new ListIter(0);
        } else {
            return list.iterator();
        }
    }


    /**
     * Search for the last occurrence of the given argument, testing
     * for equality using the <code>equals()</code> method, and return
     * the corresponding index, or -1 if the object is not found.
     *
     * @param element The element to search for
     */
    public int lastIndexOf(Object element) {

        if (fast) {
            return (list.lastIndexOf(element));
        } else {
            synchronized (list) {
                return (list.lastIndexOf(element));
            }
        }

    }


    /**
     * Return an iterator of the elements of this list, in proper sequence.
     * <p>
     * <b>Thread safety</b><br />
     * The iterator returned is thread-safe ONLY in FAST mode.
     * In slow mode there is no way to synchronize, or make the iterator thread-safe.
     * <p>
     * In fast mode iteration and modification may occur in parallel on different threads,
     * however there is a restriction. Modification must be EITHER via the Iterator
     * interface methods OR the List interface. If a mixture of modification
     * methods is used a ConcurrentModificationException is thrown from the iterator
     * modification method. If the List modification methods are used the changes are
     * NOT visible in the iterator (it shows the list contents at the time the iterator
     * was created).
     * 
     * @return the list iterator
     */
    public ListIterator listIterator() {
        if (fast) {
            return new ListIter(0);
        } else {
            return list.listIterator();
        }
    }


    /**
     * Return an iterator of the elements of this list, in proper sequence,
     * starting at the specified position.
     * <p>
     * <b>Thread safety</b><br />
     * The iterator returned is thread-safe ONLY in FAST mode.
     * In slow mode there is no way to synchronize, or make the iterator thread-safe.
     * <p>
     * In fast mode iteration and modification may occur in parallel on different threads,
     * however there is a restriction. Modification must be EITHER via the Iterator
     * interface methods OR the List interface. If a mixture of modification
     * methods is used a ConcurrentModificationException is thrown from the iterator
     * modification method. If the List modification methods are used the changes are
     * NOT visible in the iterator (it shows the list contents at the time the iterator
     * was created).
     *
     * @param index The starting position of the iterator to return
     * @return the list iterator
     * @exception IndexOutOfBoundsException if the index is out of range
     */
    public ListIterator listIterator(int index) {
        if (fast) {
            return new ListIter(index);
        } else {
            return list.listIterator(index);
        }
    }


    /**
     * Remove the element at the specified position in the list, and shift
     * any subsequent elements down one position.
     *
     * @param index Index of the element to be removed
     *
     * @exception IndexOutOfBoundsException if the index is out of range
     */
    public Object remove(int index) {

        if (fast) {
            synchronized (this) {
                ArrayList temp = (ArrayList) list.clone();
                Object result = temp.remove(index);
                list = temp;
                return (result);
            }
        } else {
            synchronized (list) {
                return (list.remove(index));
            }
        }

    }


    /**
     * Remove the first occurrence of the specified element from the list,
     * and shift any subsequent elements down one position.
     *
     * @param element Element to be removed
     */
    public boolean remove(Object element) {

        if (fast) {
            synchronized (this) {
                ArrayList temp = (ArrayList) list.clone();
                boolean result = temp.remove(element);
                list = temp;
                return (result);
            }
        } else {
            synchronized (list) {
                return (list.remove(element));
            }
        }

    }


    /**
     * Remove from this collection all of its elements that are contained
     * in the specified collection.
     *
     * @param collection Collection containing elements to be removed
     *
     * @exception UnsupportedOperationException if this optional operation
     *  is not supported by this list
     */
    public boolean removeAll(Collection collection) {

        if (fast) {
            synchronized (this) {
                ArrayList temp = (ArrayList) list.clone();
                boolean result = temp.removeAll(collection);
                list = temp;
                return (result);
            }
        } else {
            synchronized (list) {
                return (list.removeAll(collection));
            }
        }

    }


    /**
     * Remove from this collection all of its elements except those that are
     * contained in the specified collection.
     *
     * @param collection Collection containing elements to be retained
     *
     * @exception UnsupportedOperationException if this optional operation
     *  is not supported by this list
     */
    public boolean retainAll(Collection collection) {

        if (fast) {
            synchronized (this) {
                ArrayList temp = (ArrayList) list.clone();
                boolean result = temp.retainAll(collection);
                list = temp;
                return (result);
            }
        } else {
            synchronized (list) {
                return (list.retainAll(collection));
            }
        }

    }


    /**
     * Replace the element at the specified position in this list with
     * the specified element.  Returns the previous object at that position.
     * <br><br>
     * <strong>IMPLEMENTATION NOTE</strong> - This operation is specifically
     * documented to not be a structural change, so it is safe to be performed
     * without cloning.
     *
     * @param index Index of the element to replace
     * @param element The new element to be stored
     *
     * @exception IndexOutOfBoundsException if the index is out of range
     */
    public Object set(int index, Object element) {

        if (fast) {
            return (list.set(index, element));
        } else {
            synchronized (list) {
                return (list.set(index, element));
            }
        }

    }


    /**
     * Return the number of elements in this list.
     */
    public int size() {

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

    }


    /**
     * Return a view of the portion of this list between fromIndex
     * (inclusive) and toIndex (exclusive).  The returned list is backed
     * by this list, so non-structural changes in the returned list are
     * reflected in this list.  The returned list supports
     * all of the optional list operations supported by this list.
     *
     * @param fromIndex The starting index of the sublist view
     * @param toIndex The index after the end of the sublist view
     *
     * @exception IndexOutOfBoundsException if an index is out of range
     */
    public List subList(int fromIndex, int toIndex) {
        if (fast) {
            return new SubList(fromIndex, toIndex);
        } else {
            return list.subList(fromIndex, toIndex);
        }
    }


    /**
     * Return an array containing all of the elements in this list in the
     * correct order.
     */
    public Object[] toArray() {

        if (fast) {
            return (list.toArray());
        } else {
            synchronized (list) {
                return (list.toArray());
            }
        }

    }


    /**
     * Return an array containing all of the elements in this list in the
     * correct order.  The runtime type of the returned array is that of
     * the specified array.  If the list fits in the specified array, it is
     * returned therein.  Otherwise, a new array is allocated with the
     * runtime type of the specified array, and the size of this list.
     *
     * @param array Array defining the element type of the returned list
     *
     * @exception ArrayStoreException if the runtime type of <code>array</code>
     *  is not a supertype of the runtime type of every element in this list
     */
    public Object[] toArray(Object array[]) {

        if (fast) {
            return (list.toArray(array));
        } else {
            synchronized (list) {
                return (list.toArray(array));
            }
        }

    }


    /**
     * Return a String representation of this object.
     */
    public String toString() {

        StringBuffer sb = new StringBuffer("FastArrayList[");
        sb.append(list.toString());
        sb.append("]");
        return (sb.toString());

    }


    /**
     * Trim the capacity of this <code>ArrayList</code> instance to be the
     * list's current size.  An application can use this operation to minimize
     * the storage of an <code>ArrayList</code> instance.
     */
    public void trimToSize() {

        if (fast) {
            synchronized (this) {
                ArrayList temp = (ArrayList) list.clone();
                temp.trimToSize();
                list = temp;
            }
        } else {
            synchronized (list) {
                list.trimToSize();
            }
        }

    }



    private class SubList implements List {

        private int first;
        private int last;
        private List expected;


        public SubList(int first, int last) {
            this.first = first;
            this.last = last;
            this.expected = list;
        }

        private List get(List l) {
            if (list != expected) {
                throw new ConcurrentModificationException();
            }
            return l.subList(first, last);
        }

        public void clear() {
            if (fast) {
                synchronized (FastArrayList.this) {
                    ArrayList temp = (ArrayList) list.clone();
                    get(temp).clear();
                    last = first;
                    list = temp;
                    expected = temp;
                }
            } else {
                synchronized (list) {
                    get(expected).clear();
                }
            }
        }

        public boolean remove(Object o) {
            if (fast) {
                synchronized (FastArrayList.this) {
                    ArrayList temp = (ArrayList) list.clone();
                    boolean r = get(temp).remove(o);
                    if (r) last--;
                    list = temp;
                    expected = temp;
                    return r;
                }
            } else {
                synchronized (list) {
                    return get(expected).remove(o);
                }
            }
        }

        public boolean removeAll(Collection o) {
            if (fast) {
                synchronized (FastArrayList.this) {
                    ArrayList temp = (ArrayList) list.clone();