Bug 185898 ReportItemHandle needs to add two method: getAvailableDataBindingReferenceList and getDataBindingType.
ReportItemHandle needs to add two method: getAvailableDataBindingReferenceList and getDataBindingType. The first method provider the available ReportItem list of DataBindingReference. The second method provider the type of the DataBinding.
model/org.eclipse.birt.report.model.tests/test/org/eclipse/birt/report/model/api/ReportItemHandleTest.java
{
		openDesign( "ReportItemHandleTest.xml" );  
		TextItemHandle textHandle = (TextItemHandle) designHandle
				.findElement( "myText" ); 
		ComputedColumn tmpComputedColumn = new ComputedColumn( );
		tmpComputedColumn.setName( "new column1" ); 
		tmpComputedColumn.setExpression( "new column1 expr" ); 
		textHandle.addColumnBinding( tmpComputedColumn, false );
		List list = textHandle
				.getListProperty( IReportItemModel.BOUND_DATA_COLUMNS_PROP );
		assertEquals( 1, list.size( ) );
		tmpComputedColumn = new ComputedColumn( );
		tmpComputedColumn.setName( "new column1" ); 
		tmpComputedColumn.setExpression( "new column expr" ); 
		
		try
		{
			textHandle.addColumnBinding( tmpComputedColumn, false );
			fail( );
		}
		catch ( SemanticException e )
		{
			assertEquals( PropertyValueException.DESIGN_EXCEPTION_VALUE_EXISTS,
					e.getErrorCode( ) );
		}
		
		try
		{
			textHandle.addColumnBinding( tmpComputedColumn, true );
			fail( );