framework/src/org/apache/velocity/tools/view/servlet/WebappLoader.java - click - Git at Google

 /*
  * Copyright 2003-2004 The Apache Software Foundation.
  *
  * 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.apache.velocity.tools.view.servlet;

 import java.io.File;
 import java.io.InputStream;
 import java.util.HashMap;

 import javax.servlet.ServletContext;

 import org.apache.commons.collections.ExtendedProperties;
 import org.apache.velocity.exception.ResourceNotFoundException;
 import org.apache.velocity.runtime.resource.Resource;
 import org.apache.velocity.runtime.resource.loader.ResourceLoader;

 /**
  * Resource loader that uses the ServletContext of a webapp to
  * load Velocity templates.  (it's much easier to use with servlets than
  * the standard FileResourceLoader, in particular the use of war files
  * is transparent).
  *
  * The default search path is '/' (relative to the webapp root), but
  * you can change this behaviour by specifying one or more paths
  * by mean of as many webapp.resource.loader.path properties as needed
  * in the velocity.properties file.
  *
  * All paths must be relative to the root of the webapp.
  *
  * To enable caching and cache refreshing the webapp.resource.loader.cache and
  * webapp.resource.loader.modificationCheckInterval properties need to be
  * set in the velocity.properties file ... auto-reloading of global macros
  * requires the webapp.resource.loader.cache property to be set to 'false'.
  *
  * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
  * @author <a href="mailto:nathan@esha.com">Nathan Bubna</a>
  * @author <a href="mailto:claude@savoirweb.com">Claude Brisson</a>
  * @version $Id$  */

 public class WebappLoader extends ResourceLoader
 {

     /** The root paths for templates (relative to webapp's root). */
     protected String[] paths = null;
     protected HashMap templatePaths = null;

     protected ServletContext servletContext = null;

     /**
      *  This is abstract in the base class, so we need it.
      *  <br>
      *  NOTE: this expects that the ServletContext has already
      *        been placed in the runtime's application attributes
      *        under its full class name (i.e. "javax.servlet.ServletContext").
      *
      * @param configuration the {@link ExtendedProperties} associated with
      *        this resource loader.
      */
     public void init(ExtendedProperties configuration)
     {
         log.info("WebappLoader : initialization starting.");

         /* get configured paths */
         paths = configuration.getStringArray("path");
         if (paths == null || paths.length == 0)
         {
             paths = new String[1];
             paths[0] = "/";
         }
         else
         {
             /* make sure the paths end with a '/' */
             for (int i=0; i < paths.length; i++)
             {
                 if (!paths[i].endsWith("/"))
                 {
                     paths[i] += '/';
                 }
                 log.info("WebappLoader : added template path - '" + paths[i] + "'");
             }
         }

         /* get the ServletContext */
         Object obj = rsvc.getApplicationAttribute(ServletContext.class.getName());
         if (obj instanceof ServletContext)
         {
             servletContext = (ServletContext)obj;
         }
         else
         {
             log.error("WebappLoader : unable to retrieve ServletContext");
         }

         /* init the template paths map */
         templatePaths = new HashMap();

         log.info("WebappLoader : initialization complete.");
     }

     /**
      * Get an InputStream so that the Runtime can build a
      * template with it.
      *
      * @param name name of template to get
      * @return InputStream containing the template
      * @throws ResourceNotFoundException if template not found
      *         in  classpath.
      */
     public synchronized InputStream getResourceStream( String name )
         throws ResourceNotFoundException
     {
         InputStream result = null;

         if (name == null || name.length() == 0)
         {
             throw new ResourceNotFoundException ("WebappLoader : No template name provided");
         }

         /* since the paths always ends in '/',
          * make sure the name never starts with one */
         while (name.startsWith("/"))
         {
             name = name.substring(1);
         }

         Exception exception = null;
         for (int i = 0; i < paths.length; i++)
         {
             try
             {
                 result = servletContext.getResourceAsStream(paths[i] + name);

                 /* save the path and exit the loop if we found the template */
                 if (result != null)
                 {
                     templatePaths.put(name, paths[i]);
                     break;
                 }
             }
             catch (Exception e)
             {
                 /* only save the first one for later throwing */
                 if (exception == null)
                 {
                     exception = e;
                 }
             }
         }

         /* if we never found the template */
         if (result == null)
         {
             String msg;
             if (exception == null)
             {
                 msg = "WebappLoader : Resource '" + name + "' not found.";
             }
             else
             {
                 msg = exception.getMessage();
             }
             /* convert to a general Velocity ResourceNotFoundException */
             throw new ResourceNotFoundException(msg);
         }

         return result;
     }

     /**
      * Checks to see if a resource has been deleted, moved or modified.
      *
      * @param resource Resource  The resource to check for modification
      * @return boolean  True if the resource has been modified
      */
     public boolean isSourceModified(Resource resource)
     {
         String rootPath = servletContext.getRealPath("/");
         if(rootPath == null) {
            /*
             * rootPath is null if the servlet container cannot translate the
             * virtual path to a real path for any reason (such as when the
             * content is being made available from a .war archive)
             */
             return false;
         }

         /* first, try getting the previously found file */
         String fileName = resource.getName();
         String savedPath = (String)templatePaths.get(fileName);
         File cachedFile = new File(rootPath + savedPath, fileName);
         if (!cachedFile.exists())
         {
             /* then the source has been moved and/or deleted */
             return true;
         }

         /* check to see if the file can now be found elsewhere
          * before it is found in the previously saved path */
         File currentFile = null;
         for (int i = 0; i < paths.length; i++)
         {
             currentFile = new File(rootPath + paths[i], fileName);
             if (currentFile.canRead())
             {
                 /* stop at the first resource found
                  * (just like in getResourceStream()) */
                 break;
             }
         }

         /* if the current is the cached and it is readable */
         if (cachedFile.equals(currentFile) && cachedFile.canRead())
         {
             /* then (and only then) do we compare the last modified values */
             return (cachedFile.lastModified() != resource.getLastModified());
         }
         else
         {
             /* we found a new file for the resource
              * or the resource is no longer readable. */
             return true;
         }
     }

     /**
      * Checks to see when a resource was last modified
      *
      * @param resource Resource the resource to check
      * @return long The time when the resource was last modified or 0 if the file can't be read
      */
     public long getLastModified(Resource resource)
     {
         String rootPath = servletContext.getRealPath("/");
         if(rootPath == null) {
            /*
             * rootPath is null if the servlet container cannot translate the
             * virtual path to a real path for any reason (such as when the
             * content is being made available from a .war archive)
             */
             return 0;
         }

         String path = (String)templatePaths.get(resource.getName());
         File file = new File(rootPath + path, resource.getName());
         if (file.canRead())
         {
             return file.lastModified();
         }
         else
         {
             return 0;
         }
     }
 }
	/*
	* Copyright 2003-2004 The Apache Software Foundation.
	*
	* 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.apache.velocity.tools.view.servlet;

	import java.io.File;
	import java.io.InputStream;
	import java.util.HashMap;

	import javax.servlet.ServletContext;

	import org.apache.commons.collections.ExtendedProperties;
	import org.apache.velocity.exception.ResourceNotFoundException;
	import org.apache.velocity.runtime.resource.Resource;
	import org.apache.velocity.runtime.resource.loader.ResourceLoader;

	/**
	* Resource loader that uses the ServletContext of a webapp to
	* load Velocity templates. (it's much easier to use with servlets than
	* the standard FileResourceLoader, in particular the use of war files
	* is transparent).
	*
	* The default search path is '/' (relative to the webapp root), but
	* you can change this behaviour by specifying one or more paths
	* by mean of as many webapp.resource.loader.path properties as needed
	* in the velocity.properties file.
	*
	* All paths must be relative to the root of the webapp.
	*
	* To enable caching and cache refreshing the webapp.resource.loader.cache and
	* webapp.resource.loader.modificationCheckInterval properties need to be
	* set in the velocity.properties file ... auto-reloading of global macros
	* requires the webapp.resource.loader.cache property to be set to 'false'.
	*
	* @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
	* @author <a href="mailto:nathan@esha.com">Nathan Bubna</a>
	* @author <a href="mailto:claude@savoirweb.com">Claude Brisson</a>
	* @version $Id$ */

	public class WebappLoader extends ResourceLoader
	{

	/** The root paths for templates (relative to webapp's root). */
	protected String[] paths = null;
	protected HashMap templatePaths = null;

	protected ServletContext servletContext = null;

	/**
	* This is abstract in the base class, so we need it.
	* <br>
	* NOTE: this expects that the ServletContext has already
	* been placed in the runtime's application attributes
	* under its full class name (i.e. "javax.servlet.ServletContext").
	*
	* @param configuration the {@link ExtendedProperties} associated with
	* this resource loader.
	*/
	public void init(ExtendedProperties configuration)
	{
	log.info("WebappLoader : initialization starting.");

	/* get configured paths */
	paths = configuration.getStringArray("path");
	if (paths == null \|\| paths.length == 0)
	{
	paths = new String[1];
	paths[0] = "/";
	}
	else
	{
	/* make sure the paths end with a '/' */
	for (int i=0; i < paths.length; i++)
	{
	if (!paths[i].endsWith("/"))
	{
	paths[i] += '/';
	}
	log.info("WebappLoader : added template path - '" + paths[i] + "'");
	}
	}

	/* get the ServletContext */
	Object obj = rsvc.getApplicationAttribute(ServletContext.class.getName());
	if (obj instanceof ServletContext)
	{
	servletContext = (ServletContext)obj;
	}
	else
	{
	log.error("WebappLoader : unable to retrieve ServletContext");
	}

	/* init the template paths map */
	templatePaths = new HashMap();

	log.info("WebappLoader : initialization complete.");
	}

	/**
	* Get an InputStream so that the Runtime can build a
	* template with it.
	*
	* @param name name of template to get
	* @return InputStream containing the template
	* @throws ResourceNotFoundException if template not found
	* in classpath.
	*/
	public synchronized InputStream getResourceStream( String name )
	throws ResourceNotFoundException
	{
	InputStream result = null;

	if (name == null \|\| name.length() == 0)
	{
	throw new ResourceNotFoundException ("WebappLoader : No template name provided");
	}

	/* since the paths always ends in '/',
	* make sure the name never starts with one */
	while (name.startsWith("/"))
	{
	name = name.substring(1);
	}

	Exception exception = null;
	for (int i = 0; i < paths.length; i++)
	{
	try
	{
	result = servletContext.getResourceAsStream(paths[i] + name);

	/* save the path and exit the loop if we found the template */
	if (result != null)
	{
	templatePaths.put(name, paths[i]);
	break;
	}
	}
	catch (Exception e)
	{
	/* only save the first one for later throwing */
	if (exception == null)
	{
	exception = e;
	}
	}
	}

	/* if we never found the template */
	if (result == null)
	{
	String msg;
	if (exception == null)
	{
	msg = "WebappLoader : Resource '" + name + "' not found.";
	}
	else
	{
	msg = exception.getMessage();
	}
	/* convert to a general Velocity ResourceNotFoundException */
	throw new ResourceNotFoundException(msg);
	}

	return result;
	}

	/**
	* Checks to see if a resource has been deleted, moved or modified.
	*
	* @param resource Resource The resource to check for modification
	* @return boolean True if the resource has been modified
	*/
	public boolean isSourceModified(Resource resource)
	{
	String rootPath = servletContext.getRealPath("/");
	if(rootPath == null) {
	/*
	* rootPath is null if the servlet container cannot translate the
	* virtual path to a real path for any reason (such as when the
	* content is being made available from a .war archive)
	*/
	return false;
	}

	/* first, try getting the previously found file */
	String fileName = resource.getName();
	String savedPath = (String)templatePaths.get(fileName);
	File cachedFile = new File(rootPath + savedPath, fileName);
	if (!cachedFile.exists())
	{
	/* then the source has been moved and/or deleted */
	return true;
	}

	/* check to see if the file can now be found elsewhere
	* before it is found in the previously saved path */
	File currentFile = null;
	for (int i = 0; i < paths.length; i++)
	{
	currentFile = new File(rootPath + paths[i], fileName);
	if (currentFile.canRead())
	{
	/* stop at the first resource found
	* (just like in getResourceStream()) */
	break;
	}
	}

	/* if the current is the cached and it is readable */
	if (cachedFile.equals(currentFile) && cachedFile.canRead())
	{
	/* then (and only then) do we compare the last modified values */
	return (cachedFile.lastModified() != resource.getLastModified());
	}
	else
	{
	/* we found a new file for the resource
	* or the resource is no longer readable. */
	return true;
	}
	}

	/**
	* Checks to see when a resource was last modified
	*
	* @param resource Resource the resource to check
	* @return long The time when the resource was last modified or 0 if the file can't be read
	*/
	public long getLastModified(Resource resource)
	{
	String rootPath = servletContext.getRealPath("/");
	if(rootPath == null) {
	/*
	* rootPath is null if the servlet container cannot translate the
	* virtual path to a real path for any reason (such as when the
	* content is being made available from a .war archive)
	*/
	return 0;
	}

	String path = (String)templatePaths.get(resource.getName());
	File file = new File(rootPath + path, resource.getName());
	if (file.canRead())
	{
	return file.lastModified();
	}
	else
	{
	return 0;
	}
	}
	}