urldatasource.java

FMJ（freedom media for java)是java视频开发的新选择

package net.sf.fmj.media.protocol;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.media.MediaLocator;
import javax.media.Time;
import javax.media.protocol.ContentDescriptor;
import javax.media.protocol.PullDataSource;
import javax.media.protocol.PullSourceStream;
import javax.media.protocol.SourceCloneable;

import net.sf.fmj.media.MimeManager;
import net.sf.fmj.utility.LoggerSingleton;
import net.sf.fmj.utility.PathUtils;

/**
 * 
 * @author Ken Larson
 *
 */
public class URLDataSource extends PullDataSource implements SourceCloneable
{
	private static final Logger logger = LoggerSingleton.logger;
	
	protected URLConnection conn;

	protected boolean connected = false;

	private String contentTypeStr;
	private ContentDescriptor contentType;

	protected URLSourceStream[] sources;
	
	protected URLDataSource()
	{	super();
	}


	public URLDataSource(URL url)
	{	setLocator(new MediaLocator(url));
	}

	public javax.media.protocol.DataSource createClone()
	{
		final URLDataSource d;
		try
		{
			d = new URLDataSource(getLocator().getURL());
		} catch (MalformedURLException e)
		{
			logger.log(Level.WARNING, "" + e, e);
			return null;	// according to the API, return null on failure.
		}
		
		if (connected)
		{	
			try 
			{
				d.connect();
			} 
			catch (IOException e) 
			{	
				logger.log(Level.WARNING, "" + e, e);
				return null;	// according to the API, return null on failure.
			}
		}
		
		return d;	
	}
	
	public PullSourceStream[] getStreams()
	{	
		if (!connected)
			throw new Error("Unconnected source.");
		return sources;
	}
	
	/** Strips trailing ; and anything after it.  Is generally only used for multipart content. */
	private String stripTrailer(String contentType)
	{	final int index = contentType.indexOf(";");
		if (index < 0)
			return contentType;
		final String result = contentType.substring(0, index);
		return result;
		
	}

	public void connect() throws IOException
	{	
		// we allow a re-connection even if we are connected, due to an oddity in the way Manager works. See comments there 
		// in createPlayer(MediaLocator sourceLocator).
//		if (connected)	// TODO: FMJ tends to call this twice.  Check with JMF to see if that is normal.
//			return;
		
		final URL url = getLocator().getURL();
		
		conn = url.openConnection();
		
		if (conn instanceof HttpURLConnection)
		{	// TODO: this is probably why JMF has explicit HTTP and FTP data sources - so we can check things explicitly.
			final HttpURLConnection huc = (HttpURLConnection) conn;
			huc.connect();
			
			final int code = huc.getResponseCode();
			if (!(code >= 200 && code < 300))
			{	huc.disconnect();
				throw new IOException("HTTP response code: " + code);
			}	
			
			// some web servers will give the wrong content type.  It is hard to say whether we should just
			// always ignore the web server's content type, and just check the extension, or whether we should 
			// only do it for clearly wrong types.  For now, we'll just do it for clearly wrong types.
			
			logger.finer("URL: " + url);
			logger.finer("Response code: " + code);
			logger.finer("Full content type: " + conn.getContentType());
			
			boolean contentTypeSet = false;
			if (stripTrailer(conn.getContentType()).equals("text/plain"))
			{
				// see if the URL has an extension, and guess based on that.
				final String ext = PathUtils.extractExtension(url.getPath());	// this is a bit of a hack, PathUtils.extractExtension was designed for file paths, but it works here.
				if (ext != null)
				{
					// TODO: what if ext is null?
					final String result = MimeManager.getMimeType(ext);
					if (result != null)
					{	contentTypeStr = ContentDescriptor.mimeTypeToPackageName(result);
						contentTypeSet = true;
						
						logger.fine("Received content type " + conn.getContentType() + "; overriding based on extension, to: " + result);
					}
				}

			}
			
			
				// TODO: what is the right place to apply ContentDescriptor.mimeTypeToPackageName?
			if (!contentTypeSet)
				contentTypeStr = ContentDescriptor.mimeTypeToPackageName(stripTrailer(conn.getContentType()));
			
		}
		else
		{
			conn.connect();
			// TODO: what is the right place to apply ContentDescriptor.mimeTypeToPackageName?
			contentTypeStr = ContentDescriptor.mimeTypeToPackageName(conn.getContentType());
		}
		

		contentType = new ContentDescriptor(contentTypeStr);
		sources = new URLSourceStream[1];
		sources[0] = new URLSourceStream();
		                              
		connected = true;
	}

	public String getContentType()
	{	return contentTypeStr;
	}

	public void disconnect()
	{	if (!connected)
			return;
	
		if (conn != null)
		{
			if (conn instanceof HttpURLConnection)
			{
				final HttpURLConnection huc = (HttpURLConnection) conn;
				huc.disconnect();
			}
			// TODO: others
		}
		
		connected = false;
	}

	public void start() throws java.io.IOException
	{	
		//throw new UnsupportedOperationException(); // TODO - what to do?
	}

	public void stop() throws java.io.IOException
	{	//throw new UnsupportedOperationException(); // TODO - what to do?
	}

	public Time getDuration()
	{	return Time.TIME_UNKNOWN;	// TODO: any case where we know the duration?
	}

	public Object[] getControls()
	{	return new Object[0];
	}

	public Object getControl(String controlName)
	{	return null;
	}

	class URLSourceStream implements PullSourceStream
	{

		private boolean endOfStream = false;
		public boolean endOfStream()
		{
			return endOfStream;
		}

		public ContentDescriptor getContentDescriptor()
		{
			return contentType;
		}

		public long getContentLength()
		{
			
			return conn.getContentLength();		// returns -1 if unknown, which is the same as LENGTH_UNKNOWN
		}

		public int read(byte[] buffer, int offset, int length) throws IOException
		{
			final int result = conn.getInputStream().read(buffer, offset, length);	// TODO: does this handle the requirement of not returning 0 unless passed in 0?
			if (result == -1) // end of stream
				endOfStream = true;
			
			return result;
		}

		public boolean willReadBlock()
		{
			try
			{
				return conn.getInputStream().available() <= 0;
			} catch (IOException e)
			{
				return true;
			}
		}

		public Object getControl(String controlType)
		{
			return null;
		}

		public Object[] getControls()
		{
			return new Object[0];
		}
	}
}