001    // Copyright 2007 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.tapestry5.internal.services;
016    
017    import org.apache.tapestry5.ComponentResources;
018    
019    /**
020     * A kind of callback that can easily be injected into a transformed class to perform complex work.
021     * <p/>
022     * These callbacks are often injected into a transformed component class via {@link
023     * org.apache.tapestry5.services.ClassTransformation#addInjectedField(Class, String, Object)}. Bear in mind that such
024     * callbacks must be <em>threadsafe</em>, since every instance of such a class will share a single instance of the
025     * operation.
026     */
027    public interface ComponentResourcesOperation
028    {
029        /**
030         * Perform some operation that requires the components' resources.
031         */
032        void perform(ComponentResources resources);
033    }