Update Documentation for Paint Action

Author: UltimatePea

src/actions/PaintAction.java

@@ -2,21 +2,47 @@
 
 import ui.PaintPanel;
 
+/**
+ * Paint Action abstracts a particular menu action
+ * 
+ * Override this class to create a new Action.
+ * 
+ * Perfrom action will only be called when can perform action returns true.
+ * 
+ * Most of the cases, you have to call panel.repaint() as the last statement of
+ * perform action
+ * 
+ * @author chenzb
+ *
+ */
 public abstract class PaintAction {
-	
+
 	protected PaintPanel panel;
 
-	public PaintAction(PaintPanel panel){
+	public PaintAction(PaintPanel panel) {
 		this.panel = panel;
 	}
-	
+
+	/**
+	 * Whether this action can perform. Subclasses generally base the return
+	 * value on the current selection on screen
+	 * <code>panel.getSelectTool().getSelectedComponents</code>
+	 * 
+	 * @return true if the action can be performed
+	 */
 	public abstract boolean canPerformAction();
+
 	/**
-	 * Performs this action
-	 * Subclassess must invoke panel.repaint if the action changes the panel
+	 * Performs this action Subclassess must invoke panel.repaint if the action
+	 * changes the panel
 	 */
 	public abstract void performAction();
 
+	/**
+	 * The location of this item in the menu bar.
+	 * For example, "File/Save As..", "File/Open Recent/Clear Menu"
+	 * @return
+	 */
 	public abstract String locationString();
 
 }