JAVA-757: Reverting behavioral change to CommandResult.getException. It now returns null, as before, if there is no exception, instead of throwing IllegalStateException.

Author: jyemin

src/main/com/mongodb/CommandResult.java

@@ -78,7 +78,7 @@ public MongoException getException() {
             }
         }
 
-        throw new IllegalStateException("This method should not be called if there is no exception");
+        return null;
     }
 
     /**

src/test/com/mongodb/CommandResultTest.java

@@ -22,10 +22,18 @@
 import java.net.UnknownHostException;
 
 public class CommandResultTest extends TestCase {
+    @Test
+    public void testOkCommandResult() throws UnknownHostException {
+        CommandResult commandResult = new CommandResult(new ServerAddress("localhost"));
+        commandResult.put("ok", 1);
+        assertNull(commandResult.getException());
+    }
+
     @Test
     public void testNullErrorCode() throws UnknownHostException {
         CommandResult commandResult = new CommandResult(new ServerAddress("localhost"));
         commandResult.put("ok", 0);
+        assertEquals(CommandFailureException.class, commandResult.getException().getClass());
         try {
             commandResult.throwOnError();
             fail("Should throw");
@@ -40,6 +48,7 @@ public void testCommandFailure() throws UnknownHostException {
         CommandResult commandResult = new CommandResult(new ServerAddress("localhost"));
         final DBObject result = new BasicDBObject("ok", 0.0).append("errmsg", "no not found").append("code", 5000);
         commandResult.putAll(result);
+        assertEquals(CommandFailureException.class, commandResult.getException().getClass());
         try {
             commandResult.throwOnError();
             fail("Should throw");