altoslib/altosuilib: Fix equals methods, add hashCode

Whenever we use a class as a HashMap key, that class needs to override
the equals(Object) and hashCode() methods. Otherwise, the hash table
won't work right.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/altoslib/AltosPointDouble.java b/altoslib/AltosPointDouble.java
index 4a940676..45e7785e 100644
--- a/altoslib/AltosPointDouble.java
+++ b/altoslib/AltosPointDouble.java
@@ -20,7 +20,19 @@ package org.altusmetrum.altoslib_7;
 public class AltosPointDouble {
 	public double	x, y;
 
-	public boolean equals(AltosPointDouble n) {
+	public int hashCode() {
+		return new Double(x).hashCode() ^ new Double(y).hashCode();
+	}
+
+	public boolean equals(Object o) {
+		if (o == null)
+			return false;
+
+		if (!(o instanceof AltosPointDouble))
+			return false;
+
+		AltosPointDouble n = (AltosPointDouble) o;
+
 		return n.x == x && n.y == y;
 	}