/*******************************************************************************
*
* Struts2-Conversation-Plugin - An Open Source Conversation- and Flow-Scope Solution for Struts2-based Applications
* =================================================================================================================
*
* Copyright (C) 2012 by Rees Byars
* http://code.google.com/p/struts2-conversation/
*
* **********************************************************************************************************************
*
* Licensed 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.
*
* **********************************************************************************************************************
*
* $Id: ConversationInterceptor.java reesbyars $
******************************************************************************/
package com.google.code.rees.scope.struts2;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
import org.apache.struts2.StrutsStatics;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.code.rees.scope.container.ScopeContainer;
import com.google.code.rees.scope.container.ScopeContainerProvider;
import com.google.code.rees.scope.conversation.ConversationAdapter;
import com.google.code.rees.scope.conversation.ConversationConstants;
import com.google.code.rees.scope.conversation.context.ConversationContextManager;
import com.google.code.rees.scope.conversation.context.HttpConversationContextManagerProvider;
import com.google.code.rees.scope.conversation.exceptions.ConversationException;
import com.google.code.rees.scope.conversation.exceptions.ConversationIdException;
import com.google.code.rees.scope.conversation.processing.ConversationProcessor;
import com.google.code.rees.scope.conversation.processing.InjectionConversationProcessor;
import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ActionProxy;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.Interceptor;
import com.opensymphony.xwork2.interceptor.PreResultListener;
import com.opensymphony.xwork2.util.LocalizedTextUtil;
/**
*
* This interceptor uses an {@link InjectionConversationProcessor} to process conversation states and scopes.
*
* @author rees.byars
*
*/
public class ConversationInterceptor implements Interceptor {
private static final long serialVersionUID = -72776817859403642L;
private static final Logger LOG = LoggerFactory.getLogger(ConversationInterceptor.class);
/**
* This key can be used in a message resource bundle to specify a message in the case of a user
* submitting a request with an invalid conversation ID (i.e. the conversation has already ended or expired)
* and also to map results as this will be the result value
*/
public static final String CONVERSATION_ID_EXCEPTION_KEY = "struts.conversation.invalid.id";
/**
* This key can be used in a message resource bundle to specify a message in the case of a an
* unexpected error occurring during conversation processing and also to map results as this will
* be the result value.
* <p>
* Of course, we don't expect that this will happen ;)
*/
public static final String CONVERSATION_EXCEPTION_KEY = "struts.conversation.general.error";
/**
* In the case of an invalid id result, this key can be used to retrieve the offending
* conversation's name from the {@link com.opensymphony.xwork2.util.ValueStack ValueStack}.
* This value can then be referenced in a message with the expression ${conversation.name}
*/
public static final String CONVERSATION_EXCEPTION_NAME_STACK_KEY = "conversation.name";
/**
* In the case of an invalid id result, this key can be used to retrieve the offending
* conversation ID from the {@link com.opensymphony.xwork2.util.ValueStack ValueStack}.
* This value can then be referenced in a message with the expression ${conversation.id}
*/
public static final String CONVERSATION_EXCEPTION_ID_STACK_KEY = "conversation.id";
protected static final String ID_PARAM_REGEX = ".*" + ConversationConstants.CONVERSATION_NAME_SUFFIX;
protected static final Pattern ID_PARAM_PATTERN = Pattern.compile(ID_PARAM_REGEX);
protected HttpConversationContextManagerProvider contextManagerProvider;
protected ConversationProcessor processor;
protected ScopeContainer scopeContainer;
@Inject
public void setScopeContainerProvider(ScopeContainerProvider scopeContainerProvider) {
scopeContainer = scopeContainerProvider.getScopeContainer();
}
/**
* {@inheritDoc}
*/
@Override
public void destroy() {
LOG.info("Destroying the ConversationInterceptor...");
}
/**
* {@inheritDoc}
*/
@Override
public void init() {
LOG.info("Initializing the Conversation Interceptor...");
contextManagerProvider = scopeContainer.getComponent(HttpConversationContextManagerProvider.class);
processor = scopeContainer.getComponent(ConversationProcessor.class);
LOG.info("...Conversation Interceptor successfully initialized.");
}
/**
* {@inheritDoc}
*/
@Override
public String intercept(ActionInvocation invocation) throws Exception {
try {
ActionContext actionContext = invocation.getInvocationContext();
HttpServletRequest request = (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);
ConversationContextManager contextManager = contextManagerProvider.getManager(request);
final ConversationAdapter adapter = new StrutsConversationAdapter(invocation, contextManager);
processor.processConversations(adapter);
invocation.addPreResultListener(new PreResultListener() {
@Override
public void beforeResult(ActionInvocation invocation, String resultCode) {
adapter.executePostProcessors();
invocation.getStack().getContext().put(StrutsScopeConstants.CONVERSATION_ID_MAP_STACK_KEY, adapter.getViewContext());
}
});
this.cleanupParamIds(actionContext.getParameters());
return invocation.invoke();
} catch (ConversationIdException cie) {
return this.handleIdException(invocation, cie);
} catch (ConversationException ce) {
return this.handleUnexpectedException(invocation, ce);
} finally {
ConversationAdapter.cleanup();
}
}
/**
* removes the conversation ids from the parameter map so that they are excluded from further parameter processing
*
* @param parameters a map of the request parameters
*/
protected void cleanupParamIds(Map<String, Object> parameters) {
for (Iterator<Entry<String, Object>> i = parameters.entrySet().iterator(); i.hasNext();) {
if (ID_PARAM_PATTERN.matcher(i.next().getKey()).matches()) {
i.remove();
}
}
}
/**
* Handles logging and UI messages for ConversationIdExceptions
*
* @param invocation
* @param cie
* @return
*/
protected String handleIdException(ActionInvocation invocation, ConversationIdException cie) {
LOG.warn("ConversationIdException occurred in Conversation Processing, returning result of " + CONVERSATION_ID_EXCEPTION_KEY);
Locale locale = invocation.getInvocationContext().getLocale();
Map<String, Object> stackContext = invocation.getStack().getContext();
//Placing exception details on stack for OGNL retrieval in messages
stackContext.put(CONVERSATION_EXCEPTION_NAME_STACK_KEY, cie.getConversationName());
stackContext.put(CONVERSATION_EXCEPTION_ID_STACK_KEY, cie.getConversationId());
//message key for the conversation
final String conversationSpecificMessageKey = CONVERSATION_ID_EXCEPTION_KEY + "." + cie.getConversationName();
//First, we attempt to get a conversation-specific message from a bundle
String errorMessage = LocalizedTextUtil.findText(this.getClass(), conversationSpecificMessageKey, locale);
//If conversation specific message not found, get generic message, if that not found use default
if (errorMessage == null || errorMessage.equals(conversationSpecificMessageKey)) {
errorMessage = LocalizedTextUtil.findText(this.getClass(), CONVERSATION_ID_EXCEPTION_KEY, locale,
"The workflow that you are attempting to continue has ended or expired. Your requested action was not processed.", new Object[0]);
}
if (LOG.isDebugEnabled()) {
LOG.debug("Placing Conversation Error Message on stack (key={" + CONVERSATION_ID_EXCEPTION_KEY + "}): " + errorMessage);
}
//Placing message on stack instead of in actionErrors for retrieval in UI
stackContext.put(CONVERSATION_ID_EXCEPTION_KEY, errorMessage);
this.handleConversationErrorAware(invocation.getProxy(), errorMessage);
return CONVERSATION_ID_EXCEPTION_KEY;
}
/**
* Handles logging and UI messages for ConversationExceptions
*
* @param invocation
* @param ce
* @return
*/
protected String handleUnexpectedException(ActionInvocation invocation, ConversationException ce) {
LOG.error("An unexpected exception occurred in Conversation Processing, returning result of " + CONVERSATION_EXCEPTION_KEY);
Locale locale = invocation.getInvocationContext().getLocale();
String errorMessage = LocalizedTextUtil.findText(this.getClass(), CONVERSATION_EXCEPTION_KEY, locale,
"An unexpected error occurred while processing you request. Please try again.", new Object[0]);
if (LOG.isDebugEnabled()) {
LOG.debug("Placing Conversation Error Message on stack (key={" + CONVERSATION_EXCEPTION_KEY + "}): " + errorMessage);
}
//Placing message on stack instead of in actionErrors for retrieval in UI
invocation.getStack().getContext().put(CONVERSATION_EXCEPTION_KEY, errorMessage);
this.handleConversationErrorAware(invocation.getProxy(), errorMessage);
return CONVERSATION_EXCEPTION_KEY;
}
/**
* This provides extra functionality over placing on stack in that it allows for
* easily propagating the error through a redirect using a static result param:
* <p>
* <tt><param name="conversationError">${conversationError}</param></tt>
*/
protected void handleConversationErrorAware(ActionProxy proxy, String errorMessage) {
Object action = proxy.getAction();
if (action instanceof ConversationErrorAware) {
LOG.debug("Action is an instance of ConversationErrorAware; setting conversation error.");
((ConversationErrorAware) action).setConversationError(errorMessage);
}
}
}