| /* $Id$ |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| |
| package org.apache.commons.digester; |
| |
| /** |
| * An interface that can be implemented in order to get notifications of |
| * objects being pushed onto a digester stack or popped from one. |
| * <p> |
| * Because objects are pushed onto the main object stack when a rule |
| * has created a new object, this gives the ability to intercept such |
| * operations and perform modifications on created objects. |
| * <p> |
| * One use expected for this interface is to store information about the xml |
| * line that a particular object was created from. An implementation of this |
| * interface can detect whenever an object is pushed onto the digester object |
| * stack, call Digester.getDocumentLocator() to get the location within the |
| * current xml file, and store this either on the object on the stack (if it |
| * supports some user-specific interface for this purpose), or build a map of |
| * (object->locationinfo) separately. |
| * <p> |
| * It is recommended that objects implementing this interface provide |
| * a method to set a "next" action, and invoke it from the callback |
| * methods. This allows multiple actions to be "chained" together. |
| * <p> |
| * See also Digester.setStackAction. |
| * |
| * @since 1.8 |
| */ |
| public interface StackAction { |
| /** |
| * Invoked just before an object is to be pushed onto a digester stack. |
| * |
| * @param d is the digester instance. |
| * |
| * @param stackName is the name of the stack onto which the object |
| * has been pushed. Null is passed to indicate the default stack. |
| * |
| * @param o is the object that has just been pushed. Calling peek on the |
| * specified stack will return the same object. |
| * |
| * @return the object to be pushed. Normally, parameter o is returned |
| * but this method could return an alternate object to be pushed |
| * instead (eg a proxy for the provided object). |
| */ |
| public Object onPush(Digester d, String stackName, Object o); |
| |
| /** |
| * Invoked just after an object has been popped from a digester stack. |
| * |
| * @param d is the digester instance. |
| * |
| * @param stackName is the name of the stack from which the object |
| * has been popped. Null is passed to indicate the default stack. |
| * |
| * @param o is the object that has just been popped. |
| * |
| * @return the object to be returned to the called. Normally, parameter |
| * o is returned but this method could return an alternate object. |
| */ |
| public Object onPop(Digester d, String stackName, Object o); |
| } |