Bug 179737 The MeasureHandle should be able to provide data type info
We are now allow user input expression as measure expression. However this brings difficulties in determine the data type of a measure expression evaluation result. We need MeasureHandle to be enhanced to include the data type info. Please note that data type "any" is not accepted.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/writer/ModuleWriter.java
/**
 * Represents the module writer which writes an XML file following the BIRT
 * design schema. Uses a visitor pattern to traverse each element. BIRT elements
 * support inheritance in several forms. Because of this, the module writer
 * writes only those properties "local" to the element being written -- it does
 * not write inherited properties.
 * <p>
 * Because the XML schema was designed for to be understood by humans, the
 * schema is not a literal representation of the model. Instead, properties are
 * named and grouped in a way that is easiest to explain and understand. This
 * means that the writer has to do a bit more work to write the design, the the
 * extra work here is well worth the savings to the many customers who will read
 * the design format.
 * 
 */
public abstract class ModuleWriter extends ElementVisitor
{
	/**
	 * The low-level writer that emits XML syntax.
	 */
	/**
	 * The constant for default model name space.
	 */
	final protected static String DEFAULT_NAME_SPACE = "http:www.eclipse.org/birt/2005/design"; 
	/**
	 * The XML writer.
	 */
	protected IndentableXMLWriter writer = null;
	/**
	 * The base 64 codec for embedded images.