The truth comes out, my Tuple related machinations were inspired by the need

for Triple and I couldn't very well "properly" implement Triple without first
fixing Tuple.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@2484 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/util/Triple.java

@@ -0,0 +1,86 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001-2008 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library 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
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.util;
+
+import java.io.Serializable;
+
+/**
+ * A triple of values that properly implements {@link #hashCode} and {@link #equals}.
+ */
+public class Triple<A,B,C> implements Serializable
+{
+    /** The first object. */
+    public final A a;
+
+    /** The second object. */
+    public final B b;
+
+    /** The third object. */
+    public final C c;
+
+    /**
+     * Creates a triple with the specified values.
+     */
+    public static <A, B, C> Triple<A, B, C> newTriple (A a, B b, C c)
+    {
+        return new Triple<A, B, C>(a, b, c);
+    }
+
+    /**
+     * Constructs a triple with the specified two objects.
+     */
+    public Triple (A a, B b, C c)
+    {
+        this.a = a;
+        this.b = b;
+        this.c = c;
+    }
+
+    @Override // from Object
+    public int hashCode ()
+    {
+        int value = 17;
+        value = value * 31 + ((a == null) ? 0 : a.hashCode());
+        value = value * 31 + ((b == null) ? 0 : b.hashCode());
+        value = value * 31 + ((c == null) ? 0 : c.hashCode());
+        return value;
+    }
+
+    @Override // from Object
+    public boolean equals (Object other)
+    {
+        if (!(other instanceof Triple)) {
+            return false;
+        }
+        Triple<?, ?, ?> to = (Triple<?, ?, ?>)other;
+        return ObjectUtil.equals(a, to.a) && ObjectUtil.equals(b, to.b) &&
+            ObjectUtil.equals(c, to.c);
+    }
+
+    @Override // from Object
+    public String toString ()
+    {
+        return "[a=" + a + ", b=" + b + ", c=" + c + "]";
+    }
+
+    /** Don't you go a changin'. */
+    private static final long serialVersionUID = 1;
+}