1 /* 2 * $Id: AbstractExceptionHandler.java 471754 2006-11-06 14:55:09Z husted $ 3 * 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 package org.apache.struts.chain.commands; 22 23 import org.apache.commons.logging.Log; 24 import org.apache.commons.logging.LogFactory; 25 import org.apache.struts.chain.contexts.ActionContext; 26 import org.apache.struts.config.ActionConfig; 27 import org.apache.struts.config.ExceptionConfig; 28 import org.apache.struts.config.ForwardConfig; 29 import org.apache.struts.config.ModuleConfig; 30 31 /** 32 * <p>Invoke the local or global exception handler configured for the 33 * exception class that occurred.</p> 34 * 35 * @version $Rev: 471754 $ $Date: 2005-11-12 13:01:44 -0500 (Sat, 12 Nov 2005) 36 * $ 37 */ 38 public abstract class AbstractExceptionHandler extends ActionCommandBase { 39 // ------------------------------------------------------ Instance Variables 40 41 /** 42 * Provide a Commons logging instance for this class. 43 */ 44 private static final Log LOG = 45 LogFactory.getLog(AbstractExceptionHandler.class); 46 47 // ---------------------------------------------------------- Public Methods 48 49 /** 50 * <p>Invoke the appropriate <code>Action</code> for this request, and 51 * cache the returned <code>ActionForward</code>.</p> 52 * 53 * @param actionCtx The <code>Context</code> for the current request 54 * @return <code>false</code> if a <code>ForwardConfig</code> is returned, 55 * else <code>true</code> to complete processing 56 * @throws Exception if thrown by the Action class and not declared by an 57 * Exception Handler 58 */ 59 public boolean execute(ActionContext actionCtx) 60 throws Exception { 61 // Look up the exception that was thrown 62 Exception exception = actionCtx.getException(); 63 64 if (exception == null) { 65 LOG.warn("No Exception found in ActionContext"); 66 67 return (true); 68 } 69 70 // Look up the local or global exception handler configuration 71 ExceptionConfig exceptionConfig = null; 72 ActionConfig actionConfig = actionCtx.getActionConfig(); 73 ModuleConfig moduleConfig = actionCtx.getModuleConfig(); 74 75 if (actionConfig != null) { 76 if (LOG.isDebugEnabled()) { 77 LOG.debug("See if actionConfig " + actionConfig 78 + " has an exceptionConfig for " 79 + exception.getClass().getName()); 80 } 81 82 exceptionConfig = actionConfig.findException(exception.getClass()); 83 } else if (moduleConfig != null) { 84 if (LOG.isDebugEnabled()) { 85 LOG.debug("No action yet, see if moduleConfig " + moduleConfig 86 + " has an exceptionConfig " 87 + exception.getClass().getName()); 88 } 89 90 exceptionConfig = moduleConfig.findException(exception.getClass()); 91 } 92 93 // Handle the exception in the configured manner 94 if (exceptionConfig == null) { 95 LOG.warn("Unhandled exception", exception); 96 throw exception; 97 } 98 99 ForwardConfig forwardConfig = 100 handle(actionCtx, exception, exceptionConfig, actionConfig, 101 moduleConfig); 102 103 if (forwardConfig != null) { 104 actionCtx.setForwardConfig(forwardConfig); 105 106 return (false); 107 } else { 108 return (true); 109 } 110 } 111 112 // ------------------------------------------------------- Protected Methods 113 114 /** 115 * <p>Perform the required handling of the specified exception.</p> 116 * 117 * @param context The <code>Context</code> for this request 118 * @param exception The exception being handled 119 * @param exceptionConfig The corresponding {@link ExceptionConfig} 120 * @param actionConfig The {@link ActionConfig} for this request 121 * @param moduleConfig The {@link ModuleConfig} for this request 122 * @return the <code>ForwardConfig</code> to be processed next (if any), 123 * or <code>null</code> if processing has been completed 124 * @throws Exception if there are any problems handling the exception 125 */ 126 protected abstract ForwardConfig handle(ActionContext context, 127 Exception exception, ExceptionConfig exceptionConfig, 128 ActionConfig actionConfig, ModuleConfig moduleConfig) 129 throws Exception; 130 }