/*
* Copyright 2002-2006 the original author or authors.
*
* 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.
*/
package org.springframework.web.struts;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.config.ModuleConfig;
import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
/**
* Common methods for letting Struts Actions work with a
* Spring WebApplicationContext.
*
* <p>As everything in Struts is based on concrete inheritance,
* we have to provide an Action subclass (DelegatingActionProxy) and
* two RequestProcessor subclasses (DelegatingRequestProcessor and
* DelegatingTilesRequestProcessor). The only way to share common
* functionality is a utility class like this one.
*
* @author Juergen Hoeller
* @since 1.0.2
* @see DelegatingActionProxy
* @see DelegatingRequestProcessor
* @see DelegatingTilesRequestProcessor
*/
public abstract class DelegatingActionUtils {
/**
* The name of the autowire init-param specified on the Struts ActionServlet:
* "spring.autowire"
*/
public static final String PARAM_AUTOWIRE = "spring.autowire";
/**
* The name of the dependency check init-param specified on the Struts ActionServlet:
* "spring.dependencyCheck"
*/
public static final String PARAM_DEPENDENCY_CHECK = "spring.dependencyCheck";
/**
* Value of the autowire init-param that indicates autowiring by name:
* "byName"
*/
public static final String AUTOWIRE_BY_NAME = "byName";
/**
* Value of the autowire init-param that indicates autowiring by type:
* "byType"
*/
public static final String AUTOWIRE_BY_TYPE = "byType";
private static final Log logger = LogFactory.getLog(DelegatingActionUtils.class);
/**
* Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext.
* <p>Checks for a module-specific context first, falling back to the
* context for the default module else.
* @param actionServlet the associated ActionServlet
* @param moduleConfig the associated ModuleConfig (can be <code>null</code>)
* @return the WebApplicationContext, or <code>null</code> if none
* @see ContextLoaderPlugIn#SERVLET_CONTEXT_PREFIX
*/
public static WebApplicationContext getWebApplicationContext(
ActionServlet actionServlet, ModuleConfig moduleConfig) {
WebApplicationContext wac = null;
String modulePrefix = null;
// Try module-specific attribute.
if (moduleConfig != null) {
modulePrefix = moduleConfig.getPrefix();
wac = (WebApplicationContext) actionServlet.getServletContext().getAttribute(
ContextLoaderPlugIn.SERVLET_CONTEXT_PREFIX + modulePrefix);
}
// If not found, try attribute for default module.
if (wac == null && !"".equals(modulePrefix)) {
wac = (WebApplicationContext) actionServlet.getServletContext().getAttribute(
ContextLoaderPlugIn.SERVLET_CONTEXT_PREFIX);
}
return wac;
}
/**
* Fetch ContextLoaderPlugIn's WebApplicationContext from the ServletContext.
* <p>Checks for a module-specific context first, falling back to the
* context for the default module else.
* @param actionServlet the associated ActionServlet
* @param moduleConfig the associated ModuleConfig (can be <code>null</code>)
* @return the WebApplicationContext
* @throws IllegalStateException if no WebApplicationContext could be found
* @see ContextLoaderPlugIn#SERVLET_CONTEXT_PREFIX
*/
public static WebApplicationContext getRequiredWebApplicationContext(
ActionServlet actionServlet, ModuleConfig moduleConfig) throws IllegalStateException {
WebApplicationContext wac = getWebApplicationContext(actionServlet, moduleConfig);
// If no Struts-specific context found, throw an exception.
if (wac == null) {
throw new IllegalStateException(
"Could not find ContextLoaderPlugIn's WebApplicationContext as ServletContext attribute [" +
ContextLoaderPlugIn.SERVLET_CONTEXT_PREFIX + "]: Did you register [" +
ContextLoaderPlugIn.class.getName() + "]?");
}
return wac;
}
/**
* Find most specific context available: check ContextLoaderPlugIn's
* WebApplicationContext first, fall back to root WebApplicationContext else.
* <p>When checking the ContextLoaderPlugIn context: checks for a module-specific
* context first, falling back to the context for the default module else.
* @param actionServlet the associated ActionServlet
* @param moduleConfig the associated ModuleConfig (can be <code>null</code>)
* @return the WebApplicationContext
* @throws IllegalStateException if no WebApplicationContext could be found
* @see #getWebApplicationContext
* @see org.springframework.web.context.support.WebApplicationContextUtils#getRequiredWebApplicationContext
*/
public static WebApplicationContext findRequiredWebApplicationContext(
ActionServlet actionServlet, ModuleConfig moduleConfig) throws IllegalStateException {
WebApplicationContext wac = getWebApplicationContext(actionServlet, moduleConfig);
// If no Struts-specific context found, fall back to root context.
if (wac == null) {
wac = WebApplicationContextUtils.getRequiredWebApplicationContext(actionServlet.getServletContext());
}
return wac;
}
/**
* Default implementation of Action bean determination, taking
* the mapping path and prepending the module prefix, if any.
* @param mapping the Struts ActionMapping
* @return the name of the Action bean
* @see org.apache.struts.action.ActionMapping#getPath
* @see org.apache.struts.config.ModuleConfig#getPrefix
*/
public static String determineActionBeanName(ActionMapping mapping) {
String prefix = mapping.getModuleConfig().getPrefix();
String path = mapping.getPath();
String beanName = prefix + path;
if (logger.isDebugEnabled()) {
logger.debug("DelegatingActionProxy with mapping path '" + path + "' and module prefix '" +
prefix + "' delegating to Spring bean with name [" + beanName + "]");
}
return beanName;
}
/**
* Determine the autowire mode from the "autowire" init-param of the
* Struts ActionServlet, falling back to "AUTOWIRE_BY_TYPE" as default.
* @param actionServlet the Struts ActionServlet
* @return the autowire mode to use
* @see #PARAM_AUTOWIRE
* @see #AUTOWIRE_BY_NAME
* @see #AUTOWIRE_BY_TYPE
* @see org.springframework.beans.factory.config.AutowireCapableBeanFactory#autowireBeanProperties
* @see org.springframework.beans.factory.config.AutowireCapableBeanFactory#AUTOWIRE_BY_TYPE
* @see org.springframework.beans.factory.config.AutowireCapableBeanFactory#AUTOWIRE_BY_NAME
*/
public static int getAutowireMode(ActionServlet actionServlet) {
String autowire = actionServlet.getInitParameter(PARAM_AUTOWIRE);
if (autowire != null) {
if (AUTOWIRE_BY_NAME.equals(autowire)) {
return AutowireCapableBeanFactory.AUTOWIRE_BY_NAME;
}
else if (!AUTOWIRE_BY_TYPE.equals(autowire)) {
throw new IllegalArgumentException("ActionServlet 'autowire' parameter must be 'byName' or 'byType'");
}
}
return AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE;
}
/**
* Determine the dependency check to use from the "dependencyCheck" init-param
* of the Struts ActionServlet, falling back to no dependency check as default.
* @param actionServlet the Struts ActionServlet
* @return whether to enforce a dependency check or not
* @see #PARAM_DEPENDENCY_CHECK
* @see org.springframework.beans.factory.config.AutowireCapableBeanFactory#autowireBeanProperties
*/
public static boolean getDependencyCheck(ActionServlet actionServlet) {
String dependencyCheck = actionServlet.getInitParameter(PARAM_DEPENDENCY_CHECK);
return Boolean.valueOf(dependencyCheck).booleanValue();
}
}