Closing a Mongo instance now waits for the cleaner

[http://jira.mongodb.org/browse/JAVA-306]
Mongo.close() now waits for the DBCleaner thread to finish
before returning.

Author: seanjreilly

src/main/com/mongodb/Mongo.java

@@ -444,6 +444,12 @@ public List<ServerAddress> getServerAddressList() {
      */
     public void close(){
         _connector.close();
+        _cleaner.interrupt();
+        try {
+            _cleaner.join();
+        } catch (InterruptedException e) {
+            //end early
+        }
     }
 
     /**
@@ -615,7 +621,11 @@ class DBCleanerThread extends Thread {
         public void run() {
             while (_connector.isOpen()) {
                 try {
-                    Thread.sleep(cleanerIntervalMS);
+                    try {
+                        Thread.sleep(cleanerIntervalMS);
+                    } catch (InterruptedException e) {
+                        //caused by the Mongo instance being closed -- proceed with cleanup
+                    }
                     for (DB db : _dbs.values()) {
                         db.cleanCursors(true);
                     }

src/test/com/mongodb/MongoTest.java

@@ -19,9 +19,9 @@
 package com.mongodb;
 
 import java.io.*;
-import java.util.*;
-import java.util.regex.*;
 
+import org.testng.annotations.AfterTest;
+import org.testng.annotations.BeforeTest;
 import org.testng.annotations.Test;
 
 import com.mongodb.util.*;
@@ -34,7 +34,33 @@ public MongoTest()
     }
 
     final DB _db;
-    
+
+    int _originalCleanerIntervalMs;
+
+    @BeforeTest
+    public void setUp() {
+        _originalCleanerIntervalMs = Mongo.cleanerIntervalMS;
+    }
+
+    @Test
+    public void testClose_shouldNotReturnUntilCleanupThreadIsFinished() throws Exception {
+
+        System.out.println(Mongo.cleanerIntervalMS);
+        Mongo.cleanerIntervalMS = 250000; //set to a suitably large value to avoid race conditions in the test
+
+        Mongo mongo = new Mongo();
+        assertNotEquals(mongo._cleaner.getState(), Thread.State.NEW);
+
+        mongo.close();
+
+        assertFalse(mongo._cleaner.isAlive());
+    }
+
+    @AfterTest
+    public void tearDown() {
+        Mongo.cleanerIntervalMS = _originalCleanerIntervalMs;
+    }
+
     public static void main( String args[] )
         throws Exception {
         (new MongoTest()).runConsole();