WW-1661:

Backporting Freemarker template caching to 2.0.x tree

git-svn-id: https://svn.apache.org/repos/asf/struts/struts2/branches/STRUTS_2_0_X@560881 13f79535-47bb-0310-9956-ffa450edef68

core/src/main/java/org/apache/struts2/StrutsConstants.java

@@ -76,6 +76,9 @@ public final class StrutsConstants {
     /** The org.apache.struts2.views.freemarker.FreemarkerManager implementation class */
     public static final String STRUTS_FREEMARKER_MANAGER_CLASSNAME = "struts.freemarker.manager.classname";
 
+    /** Cache Freemarker templates */
+    public static final String STRUTS_FREEMARKER_TEMPLATES_CACHE = "struts.freemarker.templatesCache";
+
     /** org.apache.struts2.views.velocity.VelocityManager implementation class */
     public static final String STRUTS_VELOCITY_MANAGER_CLASSNAME = "struts.velocity.manager.classname";
 

core/src/main/java/org/apache/struts2/components/template/FreemarkerTemplateEngine.java

@@ -22,9 +22,7 @@ package org.apache.struts2.components.template;
 
 import java.io.IOException;
 import java.io.Writer;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 
 import javax.servlet.ServletContext;
 import javax.servlet.http.HttpServletRequest;
@@ -33,6 +31,7 @@ import javax.servlet.http.HttpServletResponse;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.struts2.ServletActionContext;
+import org.apache.struts2.StrutsConstants;
 import org.apache.struts2.views.freemarker.FreemarkerManager;
 
 import com.opensymphony.xwork2.inject.Inject;
@@ -41,8 +40,7 @@ import com.opensymphony.xwork2.ActionContext;
 import com.opensymphony.xwork2.ActionInvocation;
 import com.opensymphony.xwork2.util.ValueStack;
 
-import freemarker.template.Configuration;
-import freemarker.template.SimpleHash;
+import freemarker.template.*;
 
 /**
  * Freemarker based template engine.
@@ -51,6 +49,10 @@ public class FreemarkerTemplateEngine extends BaseTemplateEngine {
     static Class bodyContent = null;
     private FreemarkerManager freemarkerManager;
 
+    private final HashMap<String, freemarker.template.Template> templates = new HashMap<String, freemarker.template.Template>();
+    private final HashSet<String> missingTemplates = new HashSet<String>();
+    private boolean freemarkerCaching = false;
+
     static {
         try {
             bodyContent = ClassLoaderUtil.loadClass("javax.servlet.jsp.tagext.BodyContent",
@@ -88,16 +90,35 @@ public class FreemarkerTemplateEngine extends BaseTemplateEngine {
         freemarker.template.Template template = null;
         String templateName = null;
         Exception exception = null;
-        for (Iterator iterator = templates.iterator(); iterator.hasNext();) {
-            Template t = (Template) iterator.next();
+        for (Object template1 : templates) {
+            Template t = (Template) template1;
             templateName = getFinalTemplateName(t);
-            try {
-                // try to load, and if it works, stop at the first one
-                template = config.getTemplate(templateName);
-                break;
-            } catch (IOException e) {
-                if (exception == null) {
-                    exception = e;
+            if (freemarkerCaching) {
+                if (!isTemplateMissing(templateName)) {
+                    try {
+                        template = findInCache(templateName);  // look in cache first
+                        if (template == null) {
+                            // try to load, and if it works, stop at the first one
+                            template = config.getTemplate(templateName);
+                            addToCache(templateName, template);
+                        }
+                        break;
+                    } catch (IOException e) {
+                        addToMissingTemplateCache(templateName);
+                        if (exception == null) {
+                            exception = e;
+                        }
+                    }
+                }
+            } else {
+                try {
+                    // try to load, and if it works, stop at the first one
+                    template = config.getTemplate(templateName);
+                    break;
+                } catch (IOException e) {
+                    if (exception == null) {
+                        exception = e;
+                    }
                 }
             }
         }
@@ -154,4 +175,40 @@ public class FreemarkerTemplateEngine extends BaseTemplateEngine {
     protected String getSuffix() {
         return "ftl";
     }
+
+    protected void addToMissingTemplateCache(String templateName) {
+        synchronized(missingTemplates) {
+            missingTemplates.add(templateName);
+        }
+    }
+
+    protected boolean isTemplateMissing(String templateName) {
+        synchronized(missingTemplates) {
+            return missingTemplates.contains(templateName);
+        }
+    }
+
+    protected void addToCache(String templateName,
+        freemarker.template.Template template) {
+        synchronized(templates) {
+            templates.put(templateName, template);
+        }
+    }
+
+    protected freemarker.template.Template findInCache(String templateName) {
+        synchronized(templates) {
+            return templates.get(templateName);
+        }
+    }
+
+    /**
+     * Enables or disables Struts caching of Freemarker templates. By default disabled.
+     * Set struts.freemarker.templatesCache=true to enable cache
+     * @param cacheTemplates "true" if the template engine should cache freemarker template
+     * internally
+     */
+    @Inject(StrutsConstants.STRUTS_FREEMARKER_TEMPLATES_CACHE)
+    public void setCacheTemplates(String cacheTemplates) {
+        freemarkerCaching = "true".equals(cacheTemplates);
+    }
 }

core/src/main/java/org/apache/struts2/config/BeanSelectionProvider.java

@@ -163,6 +163,7 @@ public class BeanSelectionProvider implements ConfigurationProvider {
         if ("true".equalsIgnoreCase(props.getProperty(StrutsConstants.STRUTS_DEVMODE))) {
             props.setProperty(StrutsConstants.STRUTS_I18N_RELOAD, "true");
             props.setProperty(StrutsConstants.STRUTS_CONFIGURATION_XML_RELOAD, "true");
+            props.setProperty(StrutsConstants.STRUTS_FREEMARKER_TEMPLATES_CACHE, "false");
             // Convert struts properties into ones that xwork expects
             props.setProperty("devMode", "true");
         } else {

core/src/main/resources/org/apache/struts2/default.properties

@@ -164,6 +164,10 @@ struts.dispatcher.parametersWorkaround = false
 ### MUST extends off org.apache.struts2.views.freemarker.FreemarkerManager
 #struts.freemarker.manager.classname=org.apache.struts2.views.freemarker.FreemarkerManager
 
+### Enables caching of FreeMarker templates
+### Has the same effect as copying the templates under WEB_APP/templates
+struts.freemarker.templatesCache=false
+
 ### See the StrutsBeanWrapper javadocs for more information
 struts.freemarker.wrapper.altMap=true