1 files changed, 112 insertions, 0 deletions
diff --git a/CSMath/src/bezier/Holder.java b/CSMath/src/bezier/Holder.java
new file mode 100644
index 0000000..d6deba0
--- /dev/null
+++ b/CSMath/src/bezier/Holder.java
@@ -0,0 +1,112 @@
+package bezier;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.function.Consumer;
+
+/**
+ * Dummy class for holding a value, and being notified when it changes.
+ * 
+ * Essentially a pointer with change notifications.
+ * 
+ * @author bjculkin
+ *
+ * @param <E>
+ *            The type of held value.
+ */
+public class Holder<E> {
+	/*
+	 * The held value.
+	 */
+	private E val;
+
+	/*
+	 * The listeners to notify.
+	 */
+	private final List<Consumer<E>> listeners;
+
+	/**
+	 * Create a new holder holding nothing.
+	 */
+	public Holder() {
+		listeners = new LinkedList<>();
+	}
+
+	/**
+	 * Create a new holder holding a specific value.
+	 * 
+	 * @param val
+	 *            The value being held.
+	 */
+	public Holder(E val) {
+		this();
+
+		this.val = val;
+	}
+
+	/**
+	 * Get the contained value.
+	 * 
+	 * @return The contained value.
+	 */
+	public E getVal() {
+		return val;
+	}
+
+	/**
+	 * Set the contained value, and notify listeners.
+	 * 
+	 * @param val
+	 *            The new value.
+	 */
+	public void setVal(E val) {
+		this.val = val;
+
+		/*
+		 * Notify listeners.
+		 */
+		for (Consumer<E> listen : listeners) {
+			listen.accept(val);
+		}
+	}
+
+	/**
+	 * Add a listener.
+	 * 
+	 * @param listen
+	 *            The listener to add.
+	 */
+	public void addHolderListener(Consumer<E> listen) {
+		listeners.add(listen);
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + ((val == null) ? 0 : val.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Holder<?> other = (Holder<?>) obj;
+		if (val == null) {
+			if (other.val != null)
+				return false;
+		} else if (!val.equals(other.val))
+			return false;
+		return true;
+	}
+
+	@Override
+	public String toString() {
+		return "Holder [val=" + val + "]";
+	}
+}
+\ No newline at end of file