DefaultWorkflowInterceptor.java
/*
* 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.struts2.interceptor;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.reflect.MethodUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.struts2.action.Action;
import org.apache.struts2.ActionInvocation;
import org.apache.struts2.interceptor.annotations.InputConfig;
import java.io.Serial;
/**
* <!-- START SNIPPET: description -->
* <p>
* An interceptor that makes sure there are not validation, conversion or action errors before allowing the interceptor chain to continue.
* If a single FieldError or ActionError (including the ones replicated by the Message Store Interceptor in a redirection) is found, the INPUT result will be triggered.
* <b>This interceptor does not perform any validation</b>.
* </p>
*
* <p>
* This interceptor does nothing if the name of the method being invoked is specified in the <b>excludeMethods</b>
* parameter. <b>excludeMethods</b> accepts a comma-delimited list of method names. For example, requests to
* <b>foo!input.action</b> and <b>foo!back.action</b> will be skipped by this interceptor if you set the
* <b>excludeMethods</b> parameter to "input, back".
* </p>
*
* <p>
* <b>Note:</b> As this method extends off MethodFilterInterceptor, it is capable of
* deciding if it is applicable only to selective methods in the action class. This is done by adding param tags
* for the interceptor element, naming either a list of excluded method names and/or a list of included method
* names, whereby includeMethods overrides excludedMethods. A single * sign is interpreted as wildcard matching
* all methods for both parameters.
* See {@link MethodFilterInterceptor} for more info.
* </p>
*
* <p>
* This interceptor also supports the following interfaces which can implemented by actions:
* </p>
*
* <ul>
* <li>ValidationAware - implemented by ActionSupport class</li>
* <li>ValidationWorkflowAware - allows changing result name programmatically</li>
* <li>ValidationErrorAware - notifies action about errors and also allow change result name</li>
* </ul>
*
* <p>
* You can also use InputConfig annotation to change result name returned when validation errors occurred.
* </p>
*
* <!-- END SNIPPET: description -->
*
* <p><u>Interceptor parameters:</u></p>
*
* <!-- START SNIPPET: parameters -->
* <ul>
* <li>inputResultName - Default to "input". Determine the result name to be returned when
* an action / field error is found.</li>
* </ul>
* <!-- END SNIPPET: parameters -->
*
* <p><u>Extending the interceptor:</u></p>
*
* <!-- START SNIPPET: extending -->
*
* <p>There are no known extension points for this interceptor.</p>
*
* <!-- END SNIPPET: extending -->
*
* <p><u>Example code:</u></p>
*
* <pre>
* <!-- START SNIPPET: example -->
*
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="params"/>
* <interceptor-ref name="validation"/>
* <interceptor-ref name="workflow"/>
* <result name="success">good_result.ftl</result>
* </action>
*
* <-- In this case myMethod as well as mySecondMethod of the action class
* will not pass through the workflow process -->
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="params"/>
* <interceptor-ref name="validation"/>
* <interceptor-ref name="workflow">
* <param name="excludeMethods">myMethod,mySecondMethod</param>
* </interceptor-ref name="workflow">
* <result name="success">good_result.ftl</result>
* </action>
*
* <-- In this case, the result named "error" will be used when
* an action / field error is found -->
* <-- The Interceptor will only be applied for myWorkflowMethod method of action
* classes, since this is the only included method while any others are excluded -->
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="params"/>
* <interceptor-ref name="validation"/>
* <interceptor-ref name="workflow">
* <param name="inputResultName">error</param>
* <param name="excludeMethods">*</param>
* <param name="includeMethods">myWorkflowMethod</param>
* </interceptor-ref>
* <result name="success">good_result.ftl</result>
* </action>
*
* <!-- END SNIPPET: example -->
* </pre>
*
* @author Jason Carreira
* @author Rainer Hermanns
* @author <a href='mailto:the_mindstorm[at]evolva[dot]ro'>Alexandru Popescu</a>
* @author Philip Luppens
* @author tm_jee
*/
public class DefaultWorkflowInterceptor extends MethodFilterInterceptor {
@Serial
private static final long serialVersionUID = 7563014655616490865L;
private static final Logger LOG = LogManager.getLogger(DefaultWorkflowInterceptor.class);
private static final Class[] EMPTY_CLASS_ARRAY = new Class[0];
private String inputResultName = Action.INPUT;
/**
* Set the <code>inputResultName</code> (result name to be returned when
* a action / field error is found registered). Default to {@link Action#INPUT}
*
* @param inputResultName what result name to use when there was validation error(s).
*/
public void setInputResultName(String inputResultName) {
this.inputResultName = inputResultName;
}
/**
* Intercept {@link ActionInvocation} and returns a <code>inputResultName</code>
* when action / field errors is found registered.
*
* @param invocation the action invocation
* @return String result name
*/
@Override
protected String doIntercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();
if (action instanceof ValidationAware validationAwareAction) {
if (validationAwareAction.hasErrors()) {
LOG.debug("Errors on action [{}], returning result name [{}]", validationAwareAction, inputResultName);
String resultName = inputResultName;
resultName = processValidationWorkflowAware(action, resultName);
resultName = processInputConfig(action, invocation.getProxy().getMethod(), resultName);
resultName = processValidationErrorAware(action, resultName);
return resultName;
}
}
return invocation.invoke();
}
/**
* Process {@link ValidationWorkflowAware} interface
*
* @param action action object
* @param currentResultName current result name
*
* @return result name
*/
private String processValidationWorkflowAware(final Object action, final String currentResultName) {
String resultName = currentResultName;
if (action instanceof ValidationWorkflowAware validationWorkflowAware) {
resultName = validationWorkflowAware.getInputResultName();
LOG.debug("Changing result name from [{}] to [{}] because of processing [{}] interface applied to [{}]",
currentResultName, resultName, ValidationWorkflowAware.class.getSimpleName(), action);
}
return resultName;
}
/**
* Process {@link InputConfig} annotation applied to method
* @param action action object
* @param method method
* @param currentResultName current result name
*
* @return result name
*
* @throws Exception in case of any errors
*/
protected String processInputConfig(final Object action, final String method, final String currentResultName) throws Exception {
String resultName = currentResultName;
InputConfig annotation = MethodUtils.getAnnotation(action.getClass().getMethod(method, EMPTY_CLASS_ARRAY),
InputConfig.class ,true,true);
if (annotation != null) {
if (StringUtils.isNotEmpty(annotation.methodName())) {
resultName = (String) MethodUtils.invokeMethod(action, true, annotation.methodName());
} else {
resultName = annotation.resultName();
}
LOG.debug("Changing result name from [{}] to [{}] because of processing annotation [{}] on action [{}]",
currentResultName, resultName, InputConfig.class.getSimpleName(), action);
}
return resultName;
}
/**
* Notify action if it implements {@link ValidationErrorAware} interface
*
* @param action action object
* @param currentResultName current result name
*
* @return result name
* @see ValidationErrorAware
*/
protected String processValidationErrorAware(final Object action, final String currentResultName) {
String resultName = currentResultName;
if (action instanceof ValidationErrorAware validationErrorAware) {
resultName = validationErrorAware.actionErrorOccurred(currentResultName);
LOG.debug("Changing result name from [{}] to [{}] because of processing interface [{}] on action [{}]",
currentResultName, resultName, ValidationErrorAware.class.getSimpleName(), action);
}
return resultName;
}
}