compositecollection.java

drools 一个开放源码的规则引擎

     * the specified collection.
     *
     * @param coll
     *            the collection to check for
     * @return true if all elements contained
     */
    public boolean containsAll(Collection coll)
    {
        for ( Iterator it = coll.iterator( ); it.hasNext( ); )
        {
            if ( this.contains( it.next( ) ) == false )
            {
                return false;
            }
        }
        return true;
    }

    /**
     * Adds a collection of elements to this collection, throwing
     * UnsupportedOperationException unless a CollectionMutator strategy is
     * specified.
     *
     * @param coll
     *            the collection to add
     * @return true if the collection was modified
     * @throws UnsupportedOperationException
     *             if CollectionMutator hasn't been set
     * @throws UnsupportedOperationException
     *             if add is unsupported
     * @throws ClassCastException
     *             if the object cannot be added due to its type
     * @throws NullPointerException
     *             if the object cannot be added because its null
     * @throws IllegalArgumentException
     *             if the object cannot be added
     */
    public boolean addAll(Collection coll)
    {
        if ( this.mutator == null )
        {
            throw new UnsupportedOperationException( "addAll() is not supported on CompositeCollection without a CollectionMutator strategy" );
        }
        return this.mutator.addAll( this,
                                    this.all,
                                    coll );
    }

    /**
     * Removes the elements in the specified collection from this composite
     * collection.
     * <p>
     * This implementation calls <code>removeAll</code> on each collection.
     *
     * @param coll
     *            the collection to remove
     * @return true if the collection was modified
     * @throws UnsupportedOperationException
     *             if removeAll is unsupported
     */
    public boolean removeAll(Collection coll)
    {
        if ( coll.isEmpty( ) )
        {
            return false;
        }
        
        boolean changed = false;
        for ( int i = this.all.length - 1; i >= 0; i-- )
        {
            changed |= this.all[i].removeAll( coll );
        }
        return changed;
    }

    /**
     * Retains all the elements in the specified collection in this composite
     * collection, removing all others.
     * <p>
     * This implementation calls <code>retainAll()</code> on each collection.
     *
     * @param coll
     *            the collection to remove
     * @return true if the collection was modified
     * @throws UnsupportedOperationException
     *             if retainAll is unsupported
     */
    public boolean retainAll(final Collection coll)
    {
        boolean changed = false;
        for ( int i = this.all.length - 1; i >= 0; i-- )
        {
            changed = (this.all[i].retainAll( coll ) || changed);
        }
        return changed;
    }

    /**
     * Removes all of the elements from this collection .
     * <p>
     * This implementation calls <code>clear()</code> on each collection.
     *
     * @throws UnsupportedOperationException
     *             if clear is unsupported
     */
    public void clear()
    {
        for ( int i = 0; i < this.all.length; ++i )
        {
            this.all[i].clear( );
        }
    }

    // -----------------------------------------------------------------------
    /**
     * Specify a CollectionMutator strategy instance to handle changes.
     *
     * @param mutator
     *            the mutator to use
     */
    public void setMutator(CollectionMutator mutator)
    {
        this.mutator = mutator;
    }

    /**
     * Add these Collections to the list of collections in this composite
     *
     * @param comps
     *            Collections to be appended to the composite
     */
    public void addComposited(Collection[] comps)
    {
        ArrayList list = new ArrayList( Arrays.asList( this.all ) );
        list.addAll( Arrays.asList( comps ) );
        all = (Collection[]) list.toArray( new Collection[list.size( )] );
    }

    /**
     * Add an additional collection to this composite.
     *
     * @param c
     *            the collection to add
     */
    public void addComposited(Collection c)
    {
        this.addComposited( new Collection[]{c} );
    }

    /**
     * Add two additional collections to this composite.
     *
     * @param c
     *            the first collection to add
     * @param d
     *            the second collection to add
     */
    public void addComposited(Collection c,
                              Collection d)
    {
        this.addComposited( new Collection[]{c, d} );
    }

    /**
     * Removes a collection from the those being decorated in this composite.
     *
     * @param coll
     *            collection to be removed
     */
    public void removeComposited(Collection coll)
    {
        ArrayList list = new ArrayList( this.all.length );
        list.addAll( Arrays.asList( this.all ) );
        list.remove( coll );
        this.all = (Collection[]) list.toArray( new Collection[list.size( )] );
    }

    /**
     * Returns a new collection containing all of the elements
     *
     * @return A new ArrayList containing all of the elements in this composite.
     *         The new collection is <i>not </i> backed by this composite.
     */
    public Collection toCollection()
    {
        return new ArrayList( this );
    }

    /**
     * Gets the collections being decorated.
     *
     * @return Unmodifiable collection of all collections in this composite.
     */
    public Collection getCollections()
    {
        return Collections.unmodifiableList( Arrays.asList( this.all ) );
    }

    // -----------------------------------------------------------------------
    /**
     * Pluggable strategy to handle changes to the composite.
     */
    public interface CollectionMutator
    {

        /**
         * Called when an object is to be added to the composite.
         *
         * @param composite
         *            the CompositeCollection being changed
         * @param collections
         *            all of the Collection instances in this
         *            CompositeCollection
         * @param obj
         *            the object being added
         * @return true if the collection is changed
         * @throws UnsupportedOperationException
         *             if add is unsupported
         * @throws ClassCastException
         *             if the object cannot be added due to its type
         * @throws NullPointerException
         *             if the object cannot be added because its null
         * @throws IllegalArgumentException
         *             if the object cannot be added
         */
        public boolean add(CompositeCollection composite,
                           Collection[] collections,
                           Object obj);

        /**
         * Called when a collection is to be added to the composite.
         *
         * @param composite
         *            the CompositeCollection being changed
         * @param collections
         *            all of the Collection instances in this
         *            CompositeCollection
         * @param coll
         *            the collection being added
         * @return true if the collection is changed
         * @throws UnsupportedOperationException
         *             if add is unsupported
         * @throws ClassCastException
         *             if the object cannot be added due to its type
         * @throws NullPointerException
         *             if the object cannot be added because its null
         * @throws IllegalArgumentException
         *             if the object cannot be added
         */
        public boolean addAll(CompositeCollection composite,
                              Collection[] collections,
                              Collection coll);

        /**
         * Called when an object is to be removed to the composite.
         *
         * @param composite
         *            the CompositeCollection being changed
         * @param collections
         *            all of the Collection instances in this
         *            CompositeCollection
         * @param obj
         *            the object being removed
         * @return true if the collection is changed
         * @throws UnsupportedOperationException
         *             if removed is unsupported
         * @throws ClassCastException
         *             if the object cannot be removed due to its type
         * @throws NullPointerException
         *             if the object cannot be removed because its null
         * @throws IllegalArgumentException
         *             if the object cannot be removed
         */
        public boolean remove(CompositeCollection composite,
                              Collection[] collections,
                              Object obj);

    }

}