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Utility classes for Jetty
//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
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.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.ReadableByteChannel;
import org.eclipse.jetty.util.URIUtil;
import org.eclipse.jetty.util.thread.AutoLock;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* URL resource class.
*/
public class URLResource extends Resource
{
private static final Logger LOG = LoggerFactory.getLogger(URLResource.class);
protected final AutoLock _lock = new AutoLock();
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 boolean checkConnection()
{
try (AutoLock l = _lock.lock())
{
if (_connection == null)
{
try
{
_connection = _url.openConnection();
_connection.setUseCaches(_useCaches);
}
catch (IOException e)
{
LOG.trace("IGNORED", e);
}
}
return _connection != null;
}
}
/**
* Release any resources held by the resource.
*/
@Override
public void close()
{
try (AutoLock l = _lock.lock())
{
if (_in != null)
{
try
{
_in.close();
}
catch (IOException e)
{
LOG.trace("IGNORED", e);
}
_in = null;
}
if (_connection != null)
_connection = null;
}
}
/**
* Returns true if the represented resource exists.
*/
@Override
public boolean exists()
{
try
{
try (AutoLock l = _lock.lock())
{
if (checkConnection() && _in == null)
_in = _connection.getInputStream();
}
}
catch (IOException e)
{
LOG.trace("IGNORED", e);
}
return _in != null;
}
@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 a URI representing the given resource
*/
@Override
public URI getURI()
{
try
{
return _url.toURI();
}
catch (URISyntaxException e)
{
throw new RuntimeException(e);
}
}
/**
* Returns an File representing the given resource or NULL if this
* is not possible.
*/
@Override
public File getFile()
throws IOException
{
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 InputStream getInputStream() throws 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
* @return the inputstream for this resource
* @throws IOException if unable to open the input stream
*/
protected InputStream getInputStream(boolean resetConnection) throws IOException
{
try (AutoLock l = _lock.lock())
{
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
{
// Check that the path is within the root,
// but use the original path to create the
// resource, to preserve aliasing.
if (URIUtil.canonicalPath(path) == null)
throw new MalformedURLException(path);
return newResource(URIUtil.addEncodedPaths(_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;
}
}