/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 Nathan Bubna
* @author <a href="mailto:claude@savoirweb.com">Claude Brisson</a>
* @version $Id: WebappLoader.java 922796 2010-03-14 09:07:17Z medgar $
*/
@SuppressWarnings("unchecked")
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++)
{
String path = paths[i] + name;
try
{
result = servletContext.getResourceAsStream(path);
/* save the path and exit the loop if we found the template */
if (result != null)
{
templatePaths.put(name, paths[i]);
break;
}
}
catch (NullPointerException npe)
{
/* no servletContext was set, whine about it! */
throw npe;
}
catch (Exception e)
{
/* only save the first one for later throwing */
if (exception == null)
{
if (log.isDebugEnabled())
{
log.debug("WebappResourceLoader: Could not load "+path, e);
}
exception = e;
}
}
}
/* if we never found the template */
if (result == null)
{
String msg = "WebappLoader : Resource '" + name + "' not found.";
/* convert to a general Velocity ResourceNotFoundException */
if (exception == null)
{
throw new ResourceNotFoundException(msg);
}
else
{
msg += " Due to: " + exception;
throw new ResourceNotFoundException(msg, exception);
}
}
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();
File cachedFile = getCachedFile(rootPath, 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;
}
File cachedFile = getCachedFile(rootPath, resource.getName());
if (cachedFile.canRead())
{
return cachedFile.lastModified();
}
else
{
return 0;
}
}
private File getCachedFile(String rootPath, String fileName)
{
// we do this when we cache a resource,
// so do it again to ensure a match
while (fileName.startsWith("/"))
{
fileName = fileName.substring(1);
}
String savedPath = (String)templatePaths.get(fileName);
return new File(rootPath + savedPath, fileName);
}
}