From 8ac58b7d772a92b3d4cbcb06dba64644a3d7cd51 Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Wed, 5 Nov 2014 14:27:24 -0700
Subject: [PATCH] add minimal NavigableMap interface

---
 classpath/java/util/NavigableMap.java |  6 ++++++
 classpath/java/util/TreeMap.java      | 12 +++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 classpath/java/util/NavigableMap.java

diff --git a/classpath/java/util/NavigableMap.java b/classpath/java/util/NavigableMap.java
new file mode 100644
index 0000000000..05136159c6
--- /dev/null
+++ b/classpath/java/util/NavigableMap.java
@@ -0,0 +1,6 @@
+package java.util;
+
+public interface NavigableMap<K, V> extends SortedMap<K, V> {
+  Map.Entry<K,V> firstEntry();
+  Map.Entry<K,V> lastEntry();
+}
diff --git a/classpath/java/util/TreeMap.java b/classpath/java/util/TreeMap.java
index e7258255cd..3c4de1b141 100644
--- a/classpath/java/util/TreeMap.java
+++ b/classpath/java/util/TreeMap.java
@@ -14,7 +14,7 @@ import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 
-public class TreeMap<K,V> implements SortedMap<K,V> {
+public class TreeMap<K,V> implements NavigableMap<K,V> {
   private final Comparator<K> comparator;
   private transient TreeSet<MyEntry<K,V>> set;
 
@@ -50,6 +50,16 @@ public class TreeMap<K,V> implements SortedMap<K,V> {
     return comparator;
   }
 
+  @Override
+  public Map.Entry<K,V> firstEntry() {
+    return set.first();
+  }
+
+  @Override
+  public Map.Entry<K,V> lastEntry() {
+    return set.last();
+  }
+
   @Override
   public K firstKey() {
     return set.first().key;