Added Modifier enum

src/model/Modifier.java

+package model;
+
+public enum Modifier {
+    NONE(0x0000),
+    ALT(0x0001),
+    CTRL(0x0002),
+    /**
+     * Prevents key holding triggering multiple hotkey messages.
+     */
+    NOREPEAT(0x4000),
+    SHIFT(0x0004),
+    WIN(0x0008);
+
+    private final int val;
+
+    Modifier(int val) {
+        this.val = val;
+    }
+
+    /**
+     * Returns the Modifier integer value.
+     */
+    public int val() {
+        return val;
+    }
+
+    /**
+     * Outputs the combined values of two different given modifiers.
+     *
+     * @return The combined values of the given modifiers.
+     * 0 if there are duplicate modifiers.
+     */
+    public int combine(Modifier m1, Modifier m2) {
+        if (m1 == m2)
+            return 0;
+        else
+            return m1.val() + m2.val();
+    }
+
+    /**
+     * Outputs the combined values of the three different given modifiers.
+     * @return The combined values of the given modifiers.
+     *         0 if there are duplicate modifiers.
+     */
+    public int combine(Modifier m1, Modifier m2, Modifier m3) {
+        if (m1 == m2 || m1 == m3 || m2 == m3)
+            return 0;
+        else
+            return m1.val() + m2.val() + m3.val();
+    }
+
+    /**
+     * Outputs the combined values of the four different given modifiers.
+     * @return The combined values of the given modifiers.
+     *         0 if there are duplicate modifiers.
+     */
+    public int combine(Modifier m1, Modifier m2, Modifier m3, Modifier m4) {
+        if (m1 == m2 || m1 == m3 || m1 == m4 || m2 == m3 || m2 == m4 || m3 == m4)
+            return 0;
+        else
+            return m1.val() + m2.val() + m3.val() + m4.val();
+    }
+
+    /**
+     * Outputs the combined values of the five different given modifiers.
+     * @return The combined values of the given modifiers.
+     *         0 if there are duplicate modifiers.
+     */
+    public int combine(Modifier m1, Modifier m2, Modifier m3, Modifier m4, Modifier m5) {
+        if (m1 == m2 || m1 == m3 || m1 == m4 || m1 == m5 || m2 == m3 || m2 == m4 ||
+                m2 == m5 || m3 == m4 || m4 == m5)
+            return 0;
+        else
+            return m1.val() + m2.val() + m3.val() + m4.val() + m4.val();
+    }
+}