Modified dispatcher servlet to stick servlet context into Velocity's

application context and implemented a servlet context resource loader
which loads resources via ServletContext.getResourceAsStream().


git-svn-id: https://samskivert.googlecode.com/svn/trunk@414 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/velocity/DispatcherServlet.java

@@ -1,5 +1,5 @@
 //
-// $Id: DispatcherServlet.java,v 1.5 2001/11/01 21:34:03 mdb Exp $
+// $Id: DispatcherServlet.java,v 1.6 2001/11/02 02:03:23 mdb Exp $
 //
 // samskivert library - useful routines for java programs
 // Copyright (C) 2001 Michael Bayne
@@ -25,11 +25,13 @@ import java.util.HashMap;
 import java.util.Properties;
 
 import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 import org.apache.velocity.Template;
+import org.apache.velocity.app.Velocity;
 import org.apache.velocity.context.Context;
 import org.apache.velocity.exception.ParseErrorException;
 import org.apache.velocity.exception.ResourceNotFoundException;
@@ -167,6 +169,10 @@ public class DispatcherServlet extends VelocityServlet
 
         // Log.info("Initializing dispatcher servlet.");
 
+        // initialize the Velocity application context
+        ServletContext sctx = getServletContext();
+        Velocity.setApplicationContext(sctx);
+
         // load up our application configuration
         try {
             String appcl = config.getInitParameter(APP_CLASS_PROPS_KEY);
@@ -182,8 +188,8 @@ public class DispatcherServlet extends VelocityServlet
             if (StringUtil.blank(logicPkg)) {
                 logicPkg = "";
             }
-            _app.init(getServletContext());
-            _app.postInit(getServletContext(), logicPkg);
+            _app.init(sctx);
+            _app.postInit(sctx, logicPkg);
 
         } catch (Throwable t) {
             Log.warning("Error instantiating application.");

projects/samskivert/src/java/com/samskivert/velocity/ServletContextResourceLoader.java

@@ -0,0 +1,104 @@
+//
+// $Id: ServletContextResourceLoader.java,v 1.1 2001/11/02 02:03:23 mdb Exp $
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.velocity;
+
+import java.io.InputStream;
+import javax.servlet.ServletContext;
+
+import org.apache.commons.collections.ExtendedProperties;
+import org.apache.velocity.exception.ResourceNotFoundException;
+import org.apache.velocity.runtime.RuntimeServices;
+import org.apache.velocity.runtime.resource.Resource;
+import org.apache.velocity.runtime.resource.loader.ResourceLoader;
+
+/**
+ * A Velocity resource loader that loads resources from the servlet
+ * context.
+ *
+ * @see ServletContext#getResource
+ * @see ServletContext#getResourceAsStream
+ */
+public class ServletContextResourceLoader extends ResourceLoader
+{
+    /**
+     * Called by Velocity to initialize this resource loader.
+     */
+    public void init (ExtendedProperties config)
+    {
+        // there seems to be a tradition of logging this stuff; surely we
+        // don't want to buck tradition, do we?
+        rsvc.info("ServletContextResourceLoader: initialization starting.");
+
+        // the web framework was kind enough to slip this into the runtime
+        // instance when it started up
+        _sctx = (ServletContext)rsvc.getApplicationContext();
+
+        rsvc.info("ServletContextResourceLoader : initialization complete.");
+    }
+
+    /**
+     * Returns the input stream that can be used to load the named
+     * resource.
+     *
+     * @param path the path (relative to the webapp root) of resource to
+     * get.
+     *
+     * @return an input stream that can be used to read the resource.
+     *
+     * @exception ResourceNotFoundException if the resource was not found.
+     */
+    public InputStream getResourceStream (String path)
+        throws ResourceNotFoundException
+    {
+        InputStream stream = _sctx.getResourceAsStream(path);
+        if (stream == null) {
+            String errmsg = "Unable to load resource via servlet context " +
+                "[path=" + path + "].";
+            throw new ResourceNotFoundException(errmsg);
+        }
+        return stream;
+    }
+    
+    /**
+     * Things won't ever be modified when loaded from the servlet context
+     * because they came from the webapp .war file and if that is
+     * reloaded, everything will be thrown away and started afresh.
+     */
+    public boolean isSourceModified (Resource resource)
+    {
+        return false;
+    }
+
+    /**
+     * Things won't ever be modified when loaded from the servlet context
+     * because they came from the webapp .war file and if that is
+     * reloaded, everything will be thrown away and started afresh. So we
+     * can punt here and return zero.
+     */
+    public long getLastModified (Resource resource)
+    {
+        return 0;
+    }
+
+    /** A reference to the servlet context through which we'll load
+     * things. */
+    protected ServletContext _sctx;
+}