Create the remote xml file only once and keep it ready as a String

src/main/java/bdv/server/CellHandler.java

@@ -27,6 +27,7 @@ import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.PrintWriter;
+import java.io.StringWriter;
 
 public class CellHandler extends ContextHandler
 {
@@ -42,6 +43,9 @@ public class CellHandler extends ContextHandler
 
 	private final String dataSetURL;
 
+	// Cached XML string for provideXML()
+	private String remoteXmlString = null;
+
 	public CellHandler( final String baseUrl, final String xmlFilename ) throws SpimDataException
 	{
 		final SpimDataMinimal spimData = new XmlIoSpimDataMinimal().load( xmlFilename );
@@ -122,8 +126,9 @@ public class CellHandler extends ContextHandler
 		}
 	}
 
-	// TODO: create the remote xml file only once and keep it ready as a String
 	public void provideXML( final Request baseRequest, final HttpServletResponse response ) throws IOException, ServletException
+	{
+		if ( null == remoteXmlString )
 		{
 			try
 			{
@@ -132,47 +137,26 @@ public class CellHandler extends ContextHandler
 				final SequenceDescriptionMinimal seq = spimData.getSequenceDescription();
 				seq.setImgLoader( new RemoteImageLoader( dataSetURL ) );
 				final Document doc = new Document( io.toXml( spimData, spimData.getBasePath() ) );
-
-			response.setContentType( "application/xml" );
-			response.setStatus( HttpServletResponse.SC_OK );
-			baseRequest.setHandled( true );
 				final XMLOutputter xout = new XMLOutputter( Format.getPrettyFormat() );
-			xout.output( doc, response.getOutputStream() );
-//			xout.output( doc, System.out );
+
+				final StringWriter sw = new StringWriter();
+				xout.output( doc, sw );
+				remoteXmlString = sw.toString();
 			}
-		catch ( final Exception e )
+			catch ( final SpimDataException e )
 			{
 				throw new ServletException( e );
 			}
 
-//		final SAXBuilder sax = new SAXBuilder();
-//		Document doc;
-//		try
-//		{
-//			doc = sax.build( xmlFile );
-//		}
-//		catch ( final Exception e )
-//		{
-//			throw new ServletException( e );
-//		}
-//		final Element root = doc.getRootElement();
-//		final Element SequenceDescription = root.getChild( "SequenceDescription" );
-//		final Element ImageLoader = SequenceDescription.getChild( "ImageLoader" );
-//
-//		ImageLoader.setAttribute( "format", "bdv.remote" );
-//
-//		ImageLoader.removeChild( "hdf5" );
-//
-//		final Element baseUrl = new Element( "baseUrl" );
-//		baseUrl.setText( dataSetURL );
-//		ImageLoader.setContent( baseUrl );
-//
-//		response.setContentType( "application/xml" );
-//		response.setStatus( HttpServletResponse.SC_OK );
-//		baseRequest.setHandled( true );
-//		final PrintWriter ow = response.getWriter();
-//		ow.write( new XMLOutputter().outputString( doc ) );
-//		ow.close();
+		}
+
+		response.setContentType( "application/xml" );
+		response.setStatus( HttpServletResponse.SC_OK );
+		baseRequest.setHandled( true );
+
+		final PrintWriter ow = response.getWriter();
+		ow.write( remoteXmlString );
+		ow.close();
 	}
 
 	public String getXmlFile()