Merge pull request #797 from katzyn/TransactionMap2

Add ceilingKey() and floorKey() to TransactionMap (version 2)

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

@@ -228,9 +228,9 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
     }
 
     private void requireUnique(SearchRow row, TransactionMap<Value, Value> map, ValueArray unique) {
-        Iterator<Value> it = map.keyIterator(unique);
-        if (it.hasNext()) {
-            ValueArray k = (ValueArray) it.next();
+        Value key = map.ceilingKey(unique);
+        if (key != null) {
+            ValueArray k = (ValueArray) key;
             if (compareRows(row, convertToSearchRow(k)) == 0) {
                 // committed
                 throw getDuplicateKeyException(k.toString());

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

@@ -1320,15 +1320,10 @@ public class TransactionStore {
          */
         public K lastKey() {
             K k = map.lastKey();
-            while (true) {
-                if (k == null) {
-                    return null;
-                }
-                if (get(k) != null) {
-                    return k;
-                }
+            while (k != null && get(k) == null) {
                 k = map.lowerKey(k);
             }
+            return k;
         }
 
         /**
@@ -1339,13 +1334,22 @@ public class TransactionStore {
          * @return the result
          */
         public K higherKey(K key) {
-            while (true) {
-                K k = map.higherKey(key);
-                if (k == null || get(k) != null) {
-                    return k;
-                }
-                key = k;
+            do {
+                key = map.higherKey(key);
+            } while (key != null && get(key) == null);
+            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) {
+            Iterator<K> it = keyIterator(key);
+            return it.hasNext() ? it.next() : null;
         }
 
         /**
@@ -1365,6 +1369,22 @@ 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 = map.lowerKey(key);
+            }
+            return key;
+        }
+
         /**
          * Get the largest key that is smaller than the given key, or null if no
          * such key exists.
@@ -1373,13 +1393,10 @@ public class TransactionStore {
          * @return the result
          */
         public K lowerKey(K key) {
-            while (true) {
-                K k = map.lowerKey(key);
-                if (k == null || get(k) != null) {
-                    return k;
-                }
-                key = k;
-            }
+            do {
+                key = map.lowerKey(key);
+            } while (key != null && get(key) == null);
+            return key;
         }
 
         /**

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

@@ -22,6 +22,7 @@ import org.h2.mvstore.db.TransactionStore;
 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 +45,7 @@ public class TestTransactionStore extends TestBase {
     @Override
     public void test() throws Exception {
         FileUtils.createDirectories(getBaseDir());
+        testHCLFKey();
         testConcurrentAddRemove();
         testConcurrentAdd();
         testCountWithOpenTransactions();
@@ -62,6 +64,52 @@ 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);
+        // firstKey()
+        assertNull(map.firstKey());
+        // lastKey()
+        assertNull(map.lastKey());
+        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;