From 57b11a68e5f87c8a09cc51705adc8577ebe3dd06 Mon Sep 17 00:00:00 2001
From: Daniel Kunnath <djktno@gmail.com>
Date: Fri, 21 May 2010 22:36:14 -0600
Subject: [PATCH] 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.

---
 src/main/com/mongodb/DB.java     |   23 +++++++++++++++++++++++
 src/test/com/mongodb/DBTest.java |   22 ++++++++++++++++++++++
 2 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/src/main/com/mongodb/DB.java b/src/main/com/mongodb/DB.java
index a24808a..b375d78 100644
--- a/src/main/com/mongodb/DB.java
+++ b/src/main/com/mongodb/DB.java
@@ -215,6 +215,29 @@ public abstract class DB {
         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
index 7b6b9fb..471df7b 100644
--- a/src/test/com/mongodb/DBTest.java
+++ b/src/test/com/mongodb/DBTest.java
@@ -71,6 +71,28 @@ public class DBTest extends TestCase {
         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(){
-- 
1.7.1