package bboss.org.apache.velocity.runtime.resource.loader;
/*
* 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.
*/
import java.io.InputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import org.apache.commons.collections.ExtendedProperties;
import org.apache.commons.lang.StringUtils;
import bboss.org.apache.velocity.exception.VelocityException;
import bboss.org.apache.velocity.exception.ResourceNotFoundException;
import bboss.org.apache.velocity.runtime.resource.Resource;
/**
* This is a simple URL-based loader.
*
* @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
* @author <a href="mailto:nbubna@apache.org">Nathan Bubna</a>
* @version $Id: URLResourceLoader.java 191743 2005-06-21 23:22:20Z dlr $
* @since 1.5
*/
public class URLResourceLoader extends ResourceLoader
{
private String[] roots = null;
protected HashMap templateRoots = null;
private int timeout = -1;
private Method[] timeoutMethods;
/**
* @see bboss.org.apache.velocity.runtime.resource.loader.ResourceLoader#init(org.apache.commons.collections.ExtendedProperties)
*/
public void init(ExtendedProperties configuration)
{
log.trace("URLResourceLoader : initialization starting.");
roots = configuration.getStringArray("root");
if (log.isDebugEnabled())
{
for (int i=0; i < roots.length; i++)
{
log.debug("URLResourceLoader : adding root '" + roots[i] + "'");
}
}
timeout = configuration.getInt("timeout", -1);
if (timeout > 0)
{
try
{
Class[] types = new Class[] { Integer.TYPE };
Method conn = URLConnection.class.getMethod("setConnectTimeout", types);
Method read = URLConnection.class.getMethod("setReadTimeout", types);
timeoutMethods = new Method[] { conn, read };
log.debug("URLResourceLoader : timeout set to "+timeout);
}
catch (NoSuchMethodException nsme)
{
log.debug("URLResourceLoader : Java 1.5+ is required to customize timeout!", nsme);
timeout = -1;
}
}
// init the template paths map
templateRoots = new HashMap();
log.trace("URLResourceLoader : initialization complete.");
}
/**
* Get an InputStream so that the Runtime can build a
* template with it.
*
* @param name name of template to fetch bytestream of
* @return InputStream containing the template
* @throws ResourceNotFoundException if template not found
* in the file template path.
*/
public synchronized InputStream getResourceStream(String name)
throws ResourceNotFoundException
{
if (StringUtils.isEmpty(name))
{
throw new ResourceNotFoundException("URLResourceLoader : No template name provided");
}
InputStream inputStream = null;
Exception exception = null;
for(int i=0; i < roots.length; i++)
{
try
{
URL u = new URL(roots[i] + name);
URLConnection conn = u.openConnection();
tryToSetTimeout(conn);
inputStream = conn.getInputStream();
if (inputStream != null)
{
if (log.isDebugEnabled()) log.debug("URLResourceLoader: Found '"+name+"' at '"+roots[i]+"'");
// save this root for later re-use
templateRoots.put(name, roots[i]);
break;
}
}
catch(IOException ioe)
{
if (log.isDebugEnabled()) log.debug("URLResourceLoader: Exception when looking for '"+name+"' at '"+roots[i]+"'", ioe);
// only save the first one for later throwing
if (exception == null)
{
exception = ioe;
}
}
}
// if we never found the template
if (inputStream == null)
{
String msg;
if (exception == null)
{
msg = "URLResourceLoader : Resource '" + name + "' not found.";
}
else
{
msg = exception.getMessage();
}
// convert to a general Velocity ResourceNotFoundException
throw new ResourceNotFoundException(msg);
}
return inputStream;
}
/**
* 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, moved, or unreachable
*/
public boolean isSourceModified(Resource resource)
{
long fileLastModified = getLastModified(resource);
// if the file is unreachable or otherwise changed
if (fileLastModified == 0 ||
fileLastModified != resource.getLastModified())
{
return true;
}
return false;
}
/**
* 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 reached
*/
public long getLastModified(Resource resource)
{
// get the previously used root
String name = resource.getName();
String root = (String)templateRoots.get(name);
try
{
// get a connection to the URL
URL u = new URL(root + name);
URLConnection conn = u.openConnection();
tryToSetTimeout(conn);
return conn.getLastModified();
}
catch (IOException ioe)
{
// the file is not reachable at its previous address
String msg = "URLResourceLoader: '"+name+"' is no longer reachable at '"+root+"'";
log.error(msg, ioe);
throw new ResourceNotFoundException(msg, ioe);
}
}
/**
* Returns the current, custom timeout setting. If negative, there is no custom timeout.
* @since 1.6
*/
public int getTimeout()
{
return timeout;
}
private void tryToSetTimeout(URLConnection conn)
{
if (timeout > 0)
{
Object[] arg = new Object[] { new Integer(timeout) };
try
{
timeoutMethods[0].invoke(conn, arg);
timeoutMethods[1].invoke(conn, arg);
}
catch (Exception e)
{
String msg = "Unexpected exception while setting connection timeout for "+conn;
log.error(msg, e);
throw new VelocityException(msg, e);
}
}
}
}