Add ceilingKey() and floorKey() with tests

h2/src/main/org/h2/mvstore/db/TransactionStore.java

@@ -1345,6 +1345,22 @@ public class TransactionStore {
             return key;
         }
 
+        /**
+         * Get the smallest key that is larger than or equal to this key,
+         * or null if no such key exists.
+         *
+         * @param key the key (may not be null)
+         * @return the result
+         */
+        public K ceilingKey(K key) {
+            key = map.ceilingKey(key);
+            while (key != null && get(key) == null) {
+                // Use higherKey() for the next attempts, otherwise we'll get an infinite loop
+                key = higherKey(key);
+            }
+            return key;
+        }
+
         /**
          * Get one of the previous or next keys. There might be no value
          * available for the returned key.
@@ -1362,6 +1378,22 @@ public class TransactionStore {
             return map.getKey(index + offset);
         }
 
+        /**
+         * Get the largest key that is smaller than or equal to this key,
+         * or null if no such key exists.
+         *
+         * @param key the key (may not be null)
+         * @return the result
+         */
+        public K floorKey(K key) {
+            key = map.floorKey(key);
+            while (key != null && get(key) == null) {
+                // Use lowerKey() for the next attempts, otherwise we'll get an infinite loop
+                key = lowerKey(key);
+            }
+            return key;
+        }
+
         /**
          * Get the largest key that is smaller than the given key, or null if no
          * such key exists.

h2/src/test/org/h2/test/store/TestTransactionStore.java

@@ -19,9 +19,11 @@ import org.h2.mvstore.DataUtils;
 import org.h2.mvstore.MVMap;
 import org.h2.mvstore.MVStore;
 import org.h2.mvstore.db.TransactionStore;
+import org.h2.mvstore.db.ValueDataType;
 import org.h2.mvstore.db.TransactionStore.Change;
 import org.h2.mvstore.db.TransactionStore.Transaction;
 import org.h2.mvstore.db.TransactionStore.TransactionMap;
+import org.h2.mvstore.type.ObjectDataType;
 import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
 import org.h2.util.New;
@@ -44,6 +46,7 @@ public class TestTransactionStore extends TestBase {
     @Override
     public void test() throws Exception {
         FileUtils.createDirectories(getBaseDir());
+        testHCLFKey();
         testConcurrentAddRemove();
         testConcurrentAdd();
         testCountWithOpenTransactions();
@@ -62,6 +65,48 @@ public class TestTransactionStore extends TestBase {
         testStoreMultiThreadedReads();
     }
 
+    private void testHCLFKey() {
+        MVStore s = MVStore.open(null);
+        final TransactionStore ts = new TransactionStore(s);
+        ts.init();
+        Transaction t = ts.begin();
+        ObjectDataType keyType = new ObjectDataType();
+        TransactionMap<Long, Long> map = t.openMap("test", keyType, keyType);
+        map.put(10L, 100L);
+        map.put(20L, 200L);
+        map.put(30L, 300L);
+        map.put(40L, 400L);
+        t.commit();
+        t = ts.begin();
+        map = t.openMap("test", keyType, keyType);
+        map.put(15L, 150L);
+        // The same transaction
+        assertEquals((Object) 15L, map.higherKey(10L));
+        t = ts.begin();
+        map = t.openMap("test", keyType, keyType);
+        // Another transaction
+        // higherKey()
+        assertEquals((Object) 20L, map.higherKey(10L));
+        assertEquals((Object) 20L, map.higherKey(15L));
+        assertNull(map.higherKey(40L));
+        // ceilingKey()
+        assertEquals((Object) 10L, map.ceilingKey(10L));
+        assertEquals((Object) 20L, map.ceilingKey(15L));
+        assertEquals((Object) 40L, map.ceilingKey(40L));
+        assertNull(map.higherKey(45L));
+        // lowerKey()
+        assertNull(map.lowerKey(10L));
+        assertEquals((Object) 10L, map.lowerKey(15L));
+        assertEquals((Object) 10L, map.lowerKey(20L));
+        assertEquals((Object) 20L, map.lowerKey(25L));
+        // floorKey()
+        assertNull(map.floorKey(5L));
+        assertEquals((Object) 10L, map.floorKey(10L));
+        assertEquals((Object) 10L, map.floorKey(15L));
+        assertEquals((Object) 30L, map.floorKey(35L));
+        s.close();
+    }
+
     private static void testConcurrentAddRemove() throws InterruptedException {
         MVStore s = MVStore.open(null);
         int threadCount = 3;