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
ComputedValueHandler computedValueHandle = new ComputedValueHandler(
					this );
			return computedValueHandle
					.getAbsoluteValueForLength( dimensionValue );
		}
		assert false;
		return null;
	}
	/**
	 * Gets the default unit of the property.
	 * 
	 * @return the default unit
	 */
	public String getDefaultUnit( )
	{
		ElementPropertyDefn defn = (ElementPropertyDefn) getPropertyDefn( );
		if ( defn.getTypeCode( ) == IPropertyType.DIMENSION_TYPE )
		{
			String unit = defn.getDefaultUnit( );
			if ( !StringUtil.isBlank( unit ) )
				return unit;
			unit = getModule( ).getUnits( );
			if ( !StringUtil.isBlank( unit ) )
				return unit;
			if ( getModule( ).getSession( ) != null )
				return getModule( ).getSession( ).getUnits( );
		}
		return DimensionValue.DEFAULT_UNIT;
	}
}