Bug 36446 [Contributions] widgets: Associating Actions with Buttons
Actions can be associated with Menu items , and tool bar items using MenuManager and ToolBarManager but there is not way to associate Action with a regular button and obtaining a reference to that button the closest thing is creating an ActionContributionItem with the desired action in its constructor , then filling the parent composite with ActionContributionItem.fill(Control parent) this creats the button , but it doesn't return a reference to that button , so for example i can't give it any layout data i suggest the ActionContributionItem.fill(Control parent) returns the created widget
bundles/org.eclipse.jface/src/org/eclipse/jface/action/ActionContributionItem.java
/**
	 * Mode bit: Show text on tool items, even if an image is present. If this
	 * mode bit is not set, text is only shown on tool items if there is no
	 * image present.
	 * 
	 * @since 3.0
	 */
	public static int MODE_FORCE_TEXT = 1;
	
	private static final String ellipsis = "..."; 
	/**
	 * Stores the result of the action. False when the action returned failure.
	 */
	private Boolean result = null;
	private static boolean USE_COLOR_ICONS = true;
	/**
	 * Returns whether color icons should be used in toolbars.