Add abstract controller implementation.

diff --git a/src/main/java/net/pterodactylus/sonitus/data/controller/AbstractController.java b/src/main/java/net/pterodactylus/sonitus/data/controller/AbstractController.java
new file mode 100644 (file)
index 0000000..43276fc
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/data/controller/AbstractController.java
@@ -0,0 +1,112 @@
+/*
+ * Sonitus - AbstractController.java - Copyright © 2013 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.sonitus.data.controller;
+
+import net.pterodactylus.sonitus.data.Controller;
+
+/**
+ * Base {@link Controller} implementation that does housekeeping for the common
+ * values. Additional functionality (or an arbitrary mapping for the values of a
+ * controller) can be added in subclasses.
+ * <p/>
+ * This implementation is not thread-safe.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class AbstractController implements Controller {
+
+       /** The minimum value of this controller. */
+       private final int minimum;
+
+       /** The maximum value of this controller. */
+       private final int maximum;
+
+       /** Whether this controller has a “center” position. */
+       private final boolean centered;
+
+       /** The current value of this controller. */
+       private int value;
+
+       /**
+        * Creates a new abstract controller.
+        *
+        * @param minimum
+        *              The minimum value of the controller
+        * @param maximum
+        *              The maximum value of the controller
+        * @param centered
+        *              {@code true} if this controller has a “center” position, {@code false}
+        *              otherwise
+        * @param currentValue
+        *              The current value of this controller
+        */
+       public AbstractController(int minimum, int maximum, boolean centered, int currentValue) {
+               this.minimum = minimum;
+               this.maximum = maximum;
+               this.centered = centered;
+               value = currentValue;
+       }
+
+       //
+       // CONTROLLER METHODS
+       //
+
+       @Override
+       public int minimum() {
+               return minimum;
+       }
+
+       @Override
+       public int maximum() {
+               return maximum;
+       }
+
+       @Override
+       public boolean centered() {
+               return centered;
+       }
+
+       @Override
+       public int value() {
+               return value;
+       }
+
+       @Override
+       public void value(int value) {
+               int newValue = Math.min(maximum, Math.max(minimum, value));
+               if (newValue != this.value) {
+                       this.value = newValue;
+                       valueSet(newValue);
+               }
+       }
+
+       //
+       // SUBCLASS METHODS
+       //
+
+       /**
+        * Adjusts the controller. This method is called from {@link #value(int)} if
+        * the new value is different from the current value. Also, the value is
+        * clamped to fit within the range of this controller.
+        *
+        * @param value
+        *              The new value
+        */
+       protected abstract void valueSet(int value);
+
+}