Bug 195607 NPE is thrown when calling DimensionHandle:: getAbsoluteValue()
If a DimensionHandle did not set DimensionValue, NPE will thrown when calling DimensionHandle:: getAbsoluteValue().
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DimensionHandle.java
* Returns an array of allowed units. The set of allowed units depends on
	 * context, not all properties allow all units.
	 * 
	 * @return an array of allowed unit suffixes. Each suffix is a string.
	 */
	public IChoice[] getAllowedUnits( )
	{
		if ( memberRef == null )
			return propDefn.getAllowedChoices( ).getChoices( );
		return memberRef.getMemberDefn( ).getAllowedChoices( ).getChoices( );
	}
	/**
	 * Returns the code for the units portion of the dimension. For example, if
	 * the dimension value is "2.3cm", then the unit is "cm".
	 * 
	 * @return the units portion of the dimension. Return
	 *         <code>DimensionValue.DEFAULT_UNIT</code> if the dimension is a
	 *         predefined constant.
	 */
	public String getUnits( )
	{
		if ( isKeyword( ) )
		{
			return DimensionValue.DEFAULT_UNIT;
		}
		DimensionValue value = (DimensionValue) getValue( );
		if ( value != null )
			return value.getUnits( );
		return null;
	}