You can combine them using the bitwise OR operator,
You can specify only one alignment constant (SWT.LEFT, SWT.CENTER, or SWT.RIGHT).
Many of the styles have an effect only when creating separators
StyleDescription
SWT.SEPARATORCreates a visual divider.
SWT.HORIZONTALUsed with SWT.SEPARATOR to create a horizontal separator.
SWT.VERTICALUsed with SWT.SEPARATOR to create a vertical separator. This is the default.
SWT.SHADOW_INUsed with SWT.SEPARATOR to draw a separator that appears recessed.
SWT.SHADOW_OUTUsed with SWT.SEPARATOR to draw a separator that appears extruded.
SWT.SHADOW_NONEUsed with SWT.SEPARATOR to draw a separator that appears unshadowed.
SWT.CENTEROrients the text or image in the center of this Label.
SWT.LEFTOrients the text or image to the left of this Label.
SWT.RIGHTOrients the text or image to the right of this Label.
SWT.WRAPCreates a Label that can wrap. Support for wrapped labels depends on the layout manager and is spotty.