001    package org.apache.ojb.broker.core.proxy;
002    
003    /* Copyright 2002-2005 The Apache Software Foundation
004     *
005     * Licensed under the Apache License, Version 2.0 (the "License");
006     * you may not use this file except in compliance with the License.
007     * You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    /**
019     * Interface which Collection proxies need to implement to be
020     * treated like collection proxies in ODMG.
021     * <p> 
022     * Presently the collection proxy impl class can be plugged in and
023     * not implement this interface, but those implementations will
024     * *not* be treated as proxies by OJB
025     */
026    public interface CollectionProxy
027    {
028        /**
029         * Adds a listener to this collection.
030         *
031         * @param listener The listener to add
032         */
033        void addListener(CollectionProxyListener listener);
034    
035        /**
036         * Removes the given listener from this collecton.
037         *
038         * @param listener The listener to remove
039         */
040        void removeListener(CollectionProxyListener listener);
041    
042        /**
043         * Determines whether the collection data already has been loaded from the database.
044         *
045         * @return <code>true</code> if the data is already loaded
046         */
047        public boolean isLoaded();
048    }