EDIT

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.ModifyEvent;

import org.eclipse.swt.widgets.Display;

public class NumberWithLabelElement extends TextWithLabelElement {

	private Float start;

	private Float end;

	private NumberFormatException exception;

	/** {@inheritDoc} */

	@Override

	public void modifyText(ModifyEvent event) {

		String value = text.getText();

		if(StringUtils.isBlank(value)){

			text.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));

			super.modifyText(event);

			return;

		}

		try{

   			Float number = Float.parseFloat(value);

			if((start != null && number < start) || (end != null && number > end)){

				exception = new NumberFormatException("You entered a number that is not within the allowed bounds.");

				throw exception;

			}

		}catch(NumberFormatException e){

			text.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_RED));

			firePropertyChangeEvent(new CdmPropertyChangeEvent(this, event));

			exception = e;

			return;

		}

		exception = null;

		text.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_WHITE));

		super.modifyText(event);

	}

	/**

	 * <p>setLimits</p>

	 *

	 * @param numberOfDigits a int.

	 * @param start a {@link java.lang.Integer} object.

	 * @param end a {@link java.lang.Integer} object.

	 */

	public void setLimits(int numberOfDigits, Integer start, Integer end){

		setLimits(numberOfDigits, start.floatValue(), end.floatValue());

	}

	/**

	 * <p>setLimits</p>

	 *

	 * @param numberOfDigits a int.

	 * @param start a {@link java.lang.Float} object.

	 * @param end a {@link java.lang.Float} object.

	 */

	public void setLimits(int numberOfDigits, Float start, Float end){

		text.setTextLimit(numberOfDigits);

		this.start = start;

		this.end = end;

	}