| package org.apache.velocity.app.event; |
| |
| /* |
| * 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. |
| */ |
| |
| import org.apache.velocity.context.Context; |
| import org.apache.velocity.util.introspection.Info; |
| |
| /** |
| * Event handler called when an invalid reference is encountered. Allows |
| * the application to report errors or substitute return values. May be chained |
| * in sequence; the behavior will differ per method. |
| * |
| * <p>This feature should be regarded as experimental. |
| * |
| * @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a> |
| * @version $Id$ |
| * @since 1.5 |
| */ |
| public interface InvalidReferenceEventHandler extends EventHandler |
| { |
| |
| /** |
| * Called when object is null or there is no getter for the given |
| * property. Also called for invalid references without properties. |
| * invalidGetMethod() will be called in sequence for |
| * each link in the chain until the first non-null value is |
| * returned. |
| * |
| * @param context the context when the reference was found invalid |
| * @param reference string with complete invalid reference |
| * @param object the object referred to, or null if not found |
| * @param property the property name from the reference |
| * @param info contains template, line, column details |
| * @return substitute return value for missing reference, or null if no substitute |
| */ |
| Object invalidGetMethod(Context context, String reference, |
| Object object, String property, Info info); |
| |
| /** |
| * Called when object is null or there is no setter for the given |
| * property. invalidSetMethod() will be called in sequence for |
| * each link in the chain until a true value is returned. It's |
| * recommended that false be returned as a default to allow |
| * for easy chaining. |
| * |
| * @param context the context when the reference was found invalid |
| * @param leftreference left reference being assigned to |
| * @param rightreference invalid reference on the right |
| * @param info contains info on template, line, col |
| * |
| * @return if true then stop calling invalidSetMethod along the |
| * chain. |
| */ |
| boolean invalidSetMethod(Context context, String leftreference, |
| String rightreference, Info info); |
| |
| /** |
| * Called when object is null or the given method does not exist. |
| * invalidMethod() will be called in sequence for each link in |
| * the chain until the first non-null value is returned. |
| * |
| * @param context the context when the reference was found invalid |
| * @param reference string with complete invalid reference |
| * @param object the object referred to, or null if not found |
| * @param method the name of the (non-existent) method |
| * @param info contains template, line, column details |
| * @return substitute return value for missing reference, or null if no substitute |
| */ |
| Object invalidMethod(Context context, String reference, |
| Object object, String method, Info info); |
| } |