compositecollection.java

JAVA 文章管理系统源码

    public boolean remove(Object obj) {
        if (this.mutator == null) {
            throw new UnsupportedOperationException(
            "remove() is not supported on CompositeCollection without a CollectionMutator strategy");
        }
        return this.mutator.remove(this, this.all, obj);
    }
    
    /**
     * Checks whether this composite contains all the elements in the specified collection.
     * <p>
     * This implementation calls <code>contains()</code> for each element in 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.size() == 0) {
            return false;
        }
        boolean changed = false;
        for (int i = this.all.length - 1; i >= 0; i--) {
            changed = (this.all[i].removeAll(coll) || changed);
        }
        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 UnmodifiableList.decorate(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);
        
    }
    
}