Java tutorial
/* * Copyright 2004-2005 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.codehaus.groovy.grails.web.servlet.view; import grails.util.GrailsUtil; import groovy.lang.GroovyObject; import java.security.PrivilegedAction; import java.util.Locale; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import javax.servlet.http.HttpServletRequest; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.codehaus.groovy.grails.commons.GrailsApplication; import org.codehaus.groovy.grails.plugins.GrailsPluginManager; import org.codehaus.groovy.grails.plugins.PluginManagerAware; import org.codehaus.groovy.grails.plugins.support.aware.GrailsApplicationAware; import org.codehaus.groovy.grails.web.pages.GroovyPagesTemplateEngine; import org.codehaus.groovy.grails.web.pages.discovery.GrailsConventionGroovyPageLocator; import org.codehaus.groovy.grails.web.pages.discovery.GroovyPageScriptSource; import org.codehaus.groovy.grails.web.servlet.mvc.GrailsWebRequest; import org.codehaus.groovy.grails.web.util.CacheEntry; import org.codehaus.groovy.grails.web.util.WebUtils; import org.springframework.scripting.ScriptSource; import org.springframework.util.Assert; import org.springframework.web.servlet.View; import org.springframework.web.servlet.view.AbstractUrlBasedView; import org.springframework.web.servlet.view.InternalResourceViewResolver; /** * Evaluates the existance of a view for different extensions choosing which one to delegate to. * * @author Graeme Rocher * @since 0.1 */ public class GrailsViewResolver extends InternalResourceViewResolver implements PluginManagerAware, GrailsApplicationAware { private static final Log LOG = LogFactory.getLog(GrailsViewResolver.class); public static final String GSP_SUFFIX = ".gsp"; public static final String JSP_SUFFIX = ".jsp"; protected GroovyPagesTemplateEngine templateEngine; protected GrailsConventionGroovyPageLocator groovyPageLocator; // no need for static cache since GrailsViewResolver is in app context private Map<String, CacheEntry<View>> VIEW_CACHE = new ConcurrentHashMap<String, CacheEntry<View>>(); private GrailsApplication grailsApplication; private boolean developmentMode = GrailsUtil.isDevelopmentEnv(); private long cacheTimeout = -1; /** * Constructor. */ public GrailsViewResolver() { setCache(false); } public void setGroovyPageLocator(GrailsConventionGroovyPageLocator groovyPageLocator) { this.groovyPageLocator = groovyPageLocator; } @Override protected View loadView(String viewName, Locale locale) throws Exception { Assert.notNull(templateEngine, "Property [templateEngine] cannot be null"); if (viewName.endsWith(GSP_SUFFIX)) { viewName = viewName.substring(0, viewName.length() - GSP_SUFFIX.length()); } if (developmentMode) { return createGrailsView(viewName); } String viewCacheKey = groovyPageLocator.resolveViewFormat(viewName); CacheEntry<View> entry = VIEW_CACHE.get(viewCacheKey); final String lookupViewName = viewName; PrivilegedAction<View> updater = new PrivilegedAction<View>() { public View run() { try { return createGrailsView(lookupViewName); } catch (Exception e) { throw new WrappedInitializationException(e); } } }; View view = null; if (entry == null) { try { view = updater.run(); } catch (WrappedInitializationException e) { e.rethrow(); } entry = new CacheEntry<View>(view); VIEW_CACHE.put(viewCacheKey, entry); return view; } try { view = entry.getValue(cacheTimeout, updater); } catch (WrappedInitializationException e) { e.rethrow(); } return view; } private static class WrappedInitializationException extends RuntimeException { private static final long serialVersionUID = 1L; public WrappedInitializationException(Throwable cause) { super(cause); } public void rethrow() throws Exception { if (getCause() instanceof Exception) { throw (Exception) getCause(); } throw this; } } private View createGrailsView(String viewName) throws Exception { // try GSP if res is null GrailsWebRequest webRequest = WebUtils.retrieveGrailsWebRequest(); HttpServletRequest request = webRequest.getCurrentRequest(); GroovyObject controller = webRequest.getAttributes().getController(request); if (grailsApplication == null) { grailsApplication = getApplicationContext().getBean(GrailsApplication.APPLICATION_ID, GrailsApplication.class); } GroovyPageScriptSource scriptSource; if (controller == null) { scriptSource = groovyPageLocator.findViewByPath(viewName); } else { scriptSource = groovyPageLocator.findView(controller, viewName); } if (scriptSource != null) { return createGroovyPageView(webRequest, scriptSource.getURI(), scriptSource); } return createJstlView(viewName); } private View createGroovyPageView(GrailsWebRequest webRequest, String gspView, ScriptSource scriptSource) { if (LOG.isDebugEnabled()) { LOG.debug("Resolved GSP view at URI [" + gspView + "]"); } GroovyPageView gspSpringView = new GroovyPageView(); gspSpringView.setServletContext(webRequest.getServletContext()); gspSpringView.setUrl(gspView); gspSpringView.setApplicationContext(getApplicationContext()); gspSpringView.setTemplateEngine(templateEngine); gspSpringView.setScriptSource(scriptSource); try { gspSpringView.afterPropertiesSet(); } catch (Exception e) { throw new RuntimeException("Error initializing GroovyPageView", e); } return gspSpringView; } private View createJstlView(String viewName) throws Exception { AbstractUrlBasedView view = buildView(viewName); view.setApplicationContext(getApplicationContext()); view.afterPropertiesSet(); return view; } public void setPluginManager(GrailsPluginManager pluginManager) { // ignored, here for compatibility } public void setTemplateEngine(GroovyPagesTemplateEngine templateEngine) { this.templateEngine = templateEngine; } public void setGrailsApplication(GrailsApplication grailsApplication) { this.grailsApplication = grailsApplication; } public long getCacheTimeout() { return cacheTimeout; } public void setCacheTimeout(long cacheTimeout) { this.cacheTimeout = cacheTimeout; } }