Updated DB API to include method to check for the existence of collections without creating a new one automatically. DBTest was modified to test this behavior.

Daniel Kunnath · erh · commit 700da1afe347 · 2010-05-24T21:45:23.000+08:00
diff --git a/src/main/com/mongodb/DB.java b/src/main/com/mongodb/DB.java
@@ -215,6 +215,29 @@ public Set<String> getCollectionNames()
         return new OrderedSet<String>(tables);
     }
 
+    /**
+     * Checks to see if a collection by name %lt;name&gt; exists.
+     * @param collectionName The collection to test for existence
+     * @return false if no collection by that name exists, true if a match to an existing collection was found
+     */
+    public boolean collectionExists(String collectionName)
+    {
+        if (collectionName == null || "".equals(collectionName))
+            return false;
+
+        Set<String> collections = getCollectionNames();
+        if (collections.size() == 0)
+            return false;
+
+        for (String collection : collections)
+        {
+            if (collectionName.equalsIgnoreCase(collection))
+                return true;
+        }
+
+        return false;
+    }
+
 
     /** Returns the name of this database.
      * @return the name
diff --git a/src/test/com/mongodb/DBTest.java b/src/test/com/mongodb/DBTest.java
@@ -71,6 +71,28 @@ public void testCreateCollection() {
         assertEquals(0, 1);
     }
 
+    @Test(groups = {"basic"})
+    public void testForCollectionExistence()
+    {
+        _db.getCollection( "foo1" ).drop();
+        _db.getCollection( "foo2" ).drop();
+        _db.getCollection( "foo3" ).drop();
+        _db.getCollection( "foo4" ).drop();
+
+        assertFalse(_db.collectionExists( "foo1" ));
+
+        BasicDBObject o1 = new BasicDBObject("capped", false);
+        DBCollection c = _db.createCollection("foo1", o1);
+
+        assertTrue(_db.collectionExists( "foo1" ), "Collection 'foo' was supposed to be created, but 'collectionExists' did not return true.");
+        assertTrue(_db.collectionExists( "FOO1" ));
+        assertTrue(_db.collectionExists( "fOo1" ));
+
+        _db.getCollection( "foo1" ).drop();
+
+        assertFalse(_db.collectionExists( "foo1" ));
+    }
+
     /*public static class Person extends DBObject {
         
         public Person(){
