VirtualResource.java

package runjettyrun;


import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.channels.ReadableByteChannel;

import org.eclipse.jetty.util.resource.FileResource;
import org.eclipse.jetty.util.resource.Resource;

/**
 * 2011/5/15 Tony:
 *
 * Why we have such much unsupported method here?
 *
 * Because this one is not a delegator to real resource,
 * since it's a resource related to webapp root .
 *
 * So if system try to access this resource , it means "/" ,
 * not "/<context path>/" , so it could be some troubles.
 *
 * We wrote this just for making sure when user try to access
 * "/<context path>" with the root ResourceCollecction,
 * the Virtual Resource will bring him to real resource,
 * and it could help them to do the real operators they need. ;)
 *
 * I am not sure if that's a good implementation ,
 *
 * but it's better to be honest , we didn't support them so far
 * and don't know when user will need them at this time.
 *
 * If you found a better approach or issues related to this,
 * you could discuss it with me , tonylovejava[at]gmail.com .
 */
public class VirtualResource extends Resource {

	/**
	 *
	 */
	private static final long serialVersionUID = 8748988779292501912L;

	private Resource resource = null;
	private URL url = null;
	@SuppressWarnings("unused")
	private String resourcePath;
	private String resourcebase = null;
	private Resource webroot ;
	/**
	 *
	 * @param contextPath must start with "/"
	 * @param path
	 * @throws MalformedURLException
	 * @throws IOException
	 * @throws URISyntaxException
	 */
	public VirtualResource(Resource webroot , String contextPath,
			String path) throws MalformedURLException, IOException, URISyntaxException {

		this.webroot = webroot;
//		System.out.println("registing ["+contextPath+"] to ["+ path+"]");
		this.resourcePath = path;
		url = new File(path).toURI().toURL();
		resource = new FileResource(url);
		resourcebase = contextPath;
	}

	@Override
	public void close() {
		resource.release();
	}

	public boolean exists() {
		return resource.exists();
	}


	public boolean isDirectory() {
		return resource.isDirectory();
	}


	public long lastModified() {
		return resource.lastModified();
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public long length() {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public URL getURL() {
		throw new UnsupportedOperationException("Unsupported");
	}
	/**
	 * @throws UnsupportedOperationException
	 */
	public File getFile() throws IOException {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public String getName() {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public InputStream getInputStream() throws IOException {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public OutputStream getOutputStream() throws IOException, SecurityException {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public boolean delete() throws SecurityException {
		throw new UnsupportedOperationException("Unsupported");
	}

	/**
	 * @throws UnsupportedOperationException
	 */
	public boolean renameTo(Resource dest) throws SecurityException {
		throw new UnsupportedOperationException("Unsupported");
	}
	/**
	 * @throws UnsupportedOperationException
	 */
	public String[] list() {
		throw new UnsupportedOperationException("Unsupported");
	}


	public Resource addPath(String path) throws IOException,
			MalformedURLException {

//		System.out.println("try to addPath on virtual resourcing:"+path);
		if(!path.startsWith("/"))
			path = "/" +path;

		if(path.startsWith(this.resourcebase)){


			if(this.resourcebase.equals(path)){
//				System.out.println("got virtual resource , forward  =>"+resourcePath);
				return resource;
			}else{
//				System.out.println("got virtual resource , forward =>"+
//						resourcePath+"/"+path.substring(this.resourcebase.length()+1));
				return resource.addPath(path.substring(this.resourcebase.length()+1));

			}
		}

		//we have delegate back to webroot.
		return webroot.addPath(path);
	}

	/* test code */
	public static void main(String[] args) throws MalformedURLException, IOException, URISyntaxException {

		VirtualResource vr = new VirtualResource(
				Resource.newResource("C:/test2/"),
				"/mytest", "C:/test/");
		Resource r = vr.addPath("/mytest/test.txt");
		System.out.println(r.exists());

	}
	
	@Override
    public ReadableByteChannel getReadableByteChannel() throws IOException
    {
        return null;
    }
	public boolean isContainedIn(Resource arg0) throws MalformedURLException {
		return resource.isContainedIn(arg0);
	}


}