001    // Copyright 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.services.impl;
016    
017    import org.apache.hivemind.Locatable;
018    
019    /**
020     * Interface for an object that can provide a second, target object. This encapsulates the process
021     * of obtaining the target object (which is presumably expensive) so that the operation can be
022     * deferred or even avoided.
023     * 
024     * @author Howard M. Lewis Ship
025     * @since 4.0
026     * @see org.apache.tapestry.services.impl.DeferredObjectTranslator
027     */
028    public interface DeferredObject extends Locatable
029    {
030        /**
031         * Returns the target object. The caller is expected to cache the result, if appropriate.
032         */
033        Object getObject();
034    
035    }