    001    // Copyright 2011, 2012 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.plastic;
    016
    017    /**
    018     * Allows a listener to be notified about classes about to be loaded by the manager's class loader.
    019     * Some classes are loaded by the same class loader but not transformed (for example, inner classes). These
    020     * do not generate events. In many cases, transforming a class will cause supporting classes (representing
    021     * {@link MethodInvocation}s, and other things) to be created; these do generate events, and can be distinguished
    022     * by the {@linkplain PlasticClassEvent#getType() event's type property}.
    023     *
    024     * @see PlasticClassListenerHub
    025     */
    026    public interface PlasticClassListener
    027    {
    028        /**
    029         * Invoked just before a class is to be loaded. Separate events are fired for supporting classes before
    030         * the event for the primary class (the class being transformed or created from scratch).
    031         *
    032         * @param event
    033         *            describes the class to be loaded, and gives access to its disassembled
    034         *            bytecode (for debugging purposes)
    035         */
    036        void classWillLoad(PlasticClassEvent event);
    037    }