    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
    015package 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 */
    026public 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}