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A-Jetty Base can run on Android Java as well as on standard Java 7+ and it can run precompiled JSP/JSTL.
//
// ========================================================================
// Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.util.resource;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.ReadableByteChannel;
import java.security.Permission;
import org.eclipse.jetty.util.URIUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/* ------------------------------------------------------------ */
/** Abstract resource class.
*/
public class URLResource extends Resource
{
private static final Logger LOG = Log.getLogger(URLResource.class);
protected final URL _url;
protected final String _urlString;
protected URLConnection _connection;
protected InputStream _in=null;
transient boolean _useCaches = Resource.__defaultUseCaches;
/* ------------------------------------------------------------ */
protected URLResource(URL url, URLConnection connection)
{
_url = url;
_urlString=_url.toExternalForm();
_connection=connection;
}
/* ------------------------------------------------------------ */
protected URLResource (URL url, URLConnection connection, boolean useCaches)
{
this (url, connection);
_useCaches = useCaches;
}
/* ------------------------------------------------------------ */
protected synchronized boolean checkConnection()
{
if (_connection==null)
{
try{
_connection=_url.openConnection();
_connection.setUseCaches(_useCaches);
}
catch(IOException e)
{
LOG.ignore(e);
}
}
return _connection!=null;
}
/* ------------------------------------------------------------ */
/** Release any resources held by the resource.
*/
@Override
public synchronized void close()
{
if (_in!=null)
{
try{_in.close();}catch(IOException e){LOG.ignore(e);}
_in=null;
}
if (_connection!=null)
_connection=null;
}
/* ------------------------------------------------------------ */
/**
* Returns true if the represented resource exists.
*/
@Override
public boolean exists()
{
try
{
synchronized(this)
{
if (checkConnection() && _in==null )
_in = _connection.getInputStream();
}
}
catch (IOException e)
{
LOG.ignore(e);
}
return _in!=null;
}
/* ------------------------------------------------------------ */
/**
* Returns true if the represented resource is a container/directory.
* If the resource is not a file, resources ending with "/" are
* considered directories.
*/
@Override
public boolean isDirectory()
{
return exists() && _urlString.endsWith("/");
}
/* ------------------------------------------------------------ */
/**
* Returns the last modified time
*/
@Override
public long lastModified()
{
if (checkConnection())
return _connection.getLastModified();
return -1;
}
/* ------------------------------------------------------------ */
/**
* Return the length of the resource
*/
@Override
public long length()
{
if (checkConnection())
return _connection.getContentLength();
return -1;
}
/* ------------------------------------------------------------ */
/**
* Returns an URL representing the given resource
*/
@Override
public URL getURL()
{
return _url;
}
/* ------------------------------------------------------------ */
/**
* Returns an File representing the given resource or NULL if this
* is not possible.
*/
@Override
public File getFile()
throws IOException
{
// Try the permission hack
if (checkConnection())
{
Permission perm = _connection.getPermission();
if (perm instanceof java.io.FilePermission)
return new File(perm.getName());
}
// Try the URL file arg
try {return new File(_url.getFile());}
catch(Exception e) {LOG.ignore(e);}
// Don't know the file
return null;
}
/* ------------------------------------------------------------ */
/**
* Returns the name of the resource
*/
@Override
public String getName()
{
return _url.toExternalForm();
}
/* ------------------------------------------------------------ */
/**
* Returns an input stream to the resource. The underlying
* url connection will be nulled out to prevent re-use.
*/
@Override
public synchronized InputStream getInputStream()
throws java.io.IOException
{
return getInputStream (true); //backwards compatibility
}
/* ------------------------------------------------------------ */
/**
* Returns an input stream to the resource, optionally nulling
* out the underlying url connection. If the connection is not
* nulled out, a subsequent call to getInputStream() may return
* an existing and already in-use input stream - this depends on
* the url protocol. Eg JarURLConnection does not reuse inputstreams.
*
* @param resetConnection if true the connection field is set to null
*/
protected synchronized InputStream getInputStream(boolean resetConnection)
throws java.io.IOException
{
if (!checkConnection())
throw new IOException( "Invalid resource");
try
{
if( _in != null)
{
InputStream in = _in;
_in=null;
return in;
}
return _connection.getInputStream();
}
finally
{
if (resetConnection)
{
_connection=null;
if (LOG.isDebugEnabled()) LOG.debug("Connection nulled");
}
}
}
/* ------------------------------------------------------------ */
@Override
public ReadableByteChannel getReadableByteChannel() throws IOException
{
return null;
}
/* ------------------------------------------------------------ */
/**
* Deletes the given resource
*/
@Override
public boolean delete()
throws SecurityException
{
throw new SecurityException( "Delete not supported");
}
/* ------------------------------------------------------------ */
/**
* Rename the given resource
*/
@Override
public boolean renameTo( Resource dest)
throws SecurityException
{
throw new SecurityException( "RenameTo not supported");
}
/* ------------------------------------------------------------ */
/**
* Returns a list of resource names contained in the given resource
*/
@Override
public String[] list()
{
return null;
}
/* ------------------------------------------------------------ */
/**
* Returns the resource contained inside the current resource with the
* given name
*/
@Override
public Resource addPath(String path)
throws IOException,MalformedURLException
{
if (path==null)
return null;
path = URIUtil.canonicalPath(path);
return newResource(URIUtil.addPaths(_url.toExternalForm(),URIUtil.encodePath(path)), _useCaches);
}
/* ------------------------------------------------------------ */
@Override
public String toString()
{
return _urlString;
}
/* ------------------------------------------------------------ */
@Override
public int hashCode()
{
return _urlString.hashCode();
}
/* ------------------------------------------------------------ */
@Override
public boolean equals( Object o)
{
return o instanceof URLResource && _urlString.equals(((URLResource)o)._urlString);
}
/* ------------------------------------------------------------ */
public boolean getUseCaches ()
{
return _useCaches;
}
/* ------------------------------------------------------------ */
@Override
public boolean isContainedIn (Resource containingResource) throws MalformedURLException
{
return false;
}
}