Handy class for keeping a key+value in a sorted list or other set-like

circumstance.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1059 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/util/KeyValue.java

@@ -0,0 +1,67 @@
+//
+// $Id: KeyValue.java,v 1.1 2003/02/27 00:43:32 mdb Exp $
+
+package com.samskivert.util;
+
+/**
+ * Used to wrap a key/value pair into an object that behaves like the key
+ * but holds on to the value. This might be used to maintain a list of
+ * objects sorted by some unrelated key in a {@link SortableArrayList}.
+ * For example:
+ *
+ * <pre>
+ * SortableArrayList list = new SortableArrayList();
+ * Integer key = new Integer(4);
+ * Object value = ...;
+ * KeyValue kval = new KeyValue(key, value);
+ * list.insertSorted(kval);
+ * // ...
+ * Integer key = new Integer(4);
+ * int oidx = list.indexOf(key);
+ * Object value = (oidx == -1) ? null : list.get(oidx);
+ * </pre>
+ */
+public class KeyValue
+    implements Comparable
+{
+    /** The key in this key/value pair. */
+    public Comparable key;
+
+    /** The value in this key/value pair. */
+    public Object value;
+
+    /**
+     * Creates a key/value pair with the specified key and value.
+     */
+    public KeyValue (Comparable key, Object value)
+    {
+        this.key = key;
+        this.value = value;
+    }
+
+    // documentation inherited
+    public boolean equals (Object other)
+    {
+        if (other instanceof KeyValue) {
+            return key.equals(((KeyValue)other).key);
+        } else {
+            return false;
+        }
+    }
+
+    // documentation inherited
+    public int hashCode ()
+    {
+        return key.hashCode();
+    }
+
+    // documentation inherited
+    public int compareTo (Object other)
+    {
+        if (other instanceof KeyValue) {
+            return key.compareTo(((KeyValue)other).key);
+        } else {
+            return getClass().getName().compareTo(other.getClass().getName());
+        }
+    }
+}