public Class<? extends XtextSourceViewerConfiguration> bindSourceViewerConfiguration() {
return MyHLMSourceViewerConfiguration.class;
}

public class MyHLMSourceViewerConfiguration extends
		XtextSourceViewerConfiguration {
	
	@Override
	public ITextHover getTextHover(ISourceViewer sourceViewer, String contentType) {
		return new MyHLMTextHover(sourceViewer);
	}
}

public class MyHLMTextHover implements ITextHover, ITextHoverExtension2 {
	
	public MyHLMTextHover(ISourceViewer sourceViewer) {
		
	}

	@Override
	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
		// Deprecated by Eclipse 3.4. Do not implement!
		return null;
	}

	@Override
	public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
		return new Region(offset, 0);
	}

	@Override
	public Object getHoverInfo2(ITextViewer textViewer, IRegion hoverRegion) {
		return getHoverText(textViewer, hoverRegion);
	}

	private String getHoverText(ITextViewer textViewer, IRegion hoverRegion) {
		// Do the processing here.
		return "";
	}
}

public class MyHLMSourceViewerConfiguration extends
		XtextSourceViewerConfiguration {
	
	@Override
	public IInformationControlCreator getInformationControlCreator(ISourceViewer sourceViewer) {
		return new IInformationControlCreator() {
			
			@Override
			public IInformationControl createInformationControl(Shell parent) {
				return new DefaultInformationControl(parent, false);
			}
		};
	}

	@Override
	public ITextHover getTextHover(ISourceViewer sourceViewer, String contentType) {
			return new MyHLMBestMatchHover(sourceViewer);
	}
}

public class MyHLMBestMatchHover implements ITextHover, ITextHoverExtension2 {

	private List<ITextHoverExtension2> instantiatedTextHovers;
	
	public MyHLMBestMatchHover(ISourceViewer sourceViewer) {
		addTextHovers(sourceViewer);
	}

	private void addTextHovers(ISourceViewer sourceViewer) {
		// Add in order of precedence. Higher precedence first.
		instantiatedTextHovers = new ArrayList<ITextHoverExtension2>(2);
		// Xtext's problem hover (for syntax errors).
		instantiatedTextHovers.add(new ProblemHover(sourceViewer));
		// Our BBB information hover.
		instantiatedTextHovers.add(new MyHLMBBBHover(sourceViewer));
	}
	
	@Override
	public String getHoverInfo2(ITextViewer textViewer, IRegion hoverRegion) {
		if (instantiatedTextHovers == null) {
			return null;
		}
		for (Iterator<ITextHoverExtension2> it = instantiatedTextHovers.iterator(); it.hasNext(); ) {
			ITextHoverExtension2 hover = it.next();
			String s = (String) hover.getHoverInfo2(textViewer, hoverRegion);
			if (s != null && !s.trim().isEmpty()) {
				return s;
			}
		}
		return null;
	}
	
	@Override
	public String getHoverInfo(ITextViewer textViewer, IRegion hoverRegion) {
		return getHoverInfo2(textViewer, hoverRegion);
	}

	@Override
	public IRegion getHoverRegion(ITextViewer textViewer, int offset) {
		Point selection = textViewer.getSelectedRange();
		if (selection.x <= offset && offset < selection.x + selection.y) {
			return new Region(selection.x, selection.y);
		}
		return new Region(offset, 0);
	}
}

public class MyHLMBBBHover extends AbstractHover {
	
	private final MyHLMBBBFormatter bbbFormatter;
	
	/**
	 * Constructor.
	 * @param sourceViewer - The source viewer.
	 */
	public MyHLMBBBHover(ISourceViewer sourceViewer) {
		super(sourceViewer);
		bbbFormatter = new MyHLMBBBFormatter();
	}

	@Override
	protected String getHoverInfoInternal(final int lineNumber, final int offset) {
		try {
			IDocument doc = sourceViewer.getDocument();
			if (doc.get(offset, 1).trim().isEmpty()) {
				return null;
			}
			
			IRegion lineRegion = doc.getLineInformation(lineNumber);
			String line = doc.get(lineRegion.getOffset(), lineRegion.getLength());	
			int diff = offset - lineRegion.getOffset(); 
			int	firstSpace = 0, lastSpace = 0;
			for (int i = diff; i >= 0; i--) {
				if (!Character.isJavaIdentifierStart(line.charAt(i)) && !Character.isDigit(line.charAt(i))) {
					firstSpace = i;
					break;
				}
					
			}
			for (int i = diff; i < line.length(); i++) {
				if (!Character.isJavaIdentifierPart(line.charAt(i))) {
					lastSpace = i;
					break;
				}
			}
			if (firstSpace == lastSpace) {
				return null;
			}
			String word = line.substring(firstSpace + 1, (lastSpace > 0 ? lastSpace : line.length()));
			return bbbFormatter.getBBBDocumentation(word);
		} catch (BadLocationException e) {
			return null;
		}
	}
}