Merge remote-tracking branch 'origin/35-drop-all-data' into dev

Author: greenrobot

objectbox-java/src/main/java/io/objectbox/BoxStore.java

@@ -575,18 +575,23 @@ public static boolean deleteAllFiles(@Nullable File baseDirectoryOrNull, @Nullab
         return deleteAllFiles(dbDir);
     }
 
+    /**
+     * Removes all objects from all boxes, e.g. deletes all database content.
+     *
+     * Internally reads the current schema, drops all database content,
+     * then restores the schema in a single transaction.
+     */
+    public void removeAllObjects() {
+        nativeDropAllData(handle);
+    }
+
     @Internal
     public void unregisterTransaction(Transaction transaction) {
         synchronized (transactions) {
             transactions.remove(transaction);
         }
     }
 
-    // TODO not implemented on native side; rename to "nukeData" (?)
-    void dropAllData() {
-        nativeDropAllData(handle);
-    }
-
     void txCommitted(Transaction tx, @Nullable int[] entityTypeIdsAffected) {
         // Only one write TX at a time, but there is a chance two writers race after commit: thus synchronize
         synchronized (txCommitCountLock) {

tests/objectbox-java-test/src/test/java/io/objectbox/BoxStoreTest.java

@@ -145,6 +145,27 @@ public void testDeleteAllFiles_openStore() {
         BoxStore.deleteAllFiles(boxStoreDir);
     }
 
+    @Test
+    public void removeAllObjects() {
+        // Insert at least two different kinds.
+        store.close();
+        store.deleteAllFiles();
+        store = createBoxStoreBuilderWithTwoEntities(false).build();
+        putTestEntities(5);
+        Box<TestEntityMinimal> minimalBox = store.boxFor(TestEntityMinimal.class);
+        minimalBox.put(new TestEntityMinimal(0, "Sally"));
+        assertEquals(5, getTestEntityBox().count());
+        assertEquals(1, minimalBox.count());
+
+        store.removeAllObjects();
+        assertEquals(0, getTestEntityBox().count());
+        assertEquals(0, minimalBox.count());
+
+        // Assert inserting is still possible.
+        putTestEntities(1);
+        assertEquals(1, getTestEntityBox().count());
+    }
+
     private void closeStoreForTest() {
         assertTrue(boxStoreDir.exists());
         store.close();