DRILL-4729: Add support for prepared statement implementation on server side

+ Add following APIs for Drill Java client
  - DrillRpcFuture<CreatePreparedStatementResp> createPreparedStatement(final String query)
  - void executePreparedStatement(final PreparedStatement preparedStatement, UserResultsListener resultsListener)
  - List<QueryDataBatch> executePreparedStatement(final PreparedStatement preparedStatement) (for testing purpose)

+ Separated out the interface from UserClientConnection. It makes it easy to have wrappers which need to
  tap the messages and data going to the actual client.

+ Implement CREATE_PREPARED_STATEMENT and handle RunQuery with PreparedStatement

+ Test changes to support prepared statement as query type

+ Add tests in TestPreparedStatementProvider

this closes #530

1 files changed, 3 insertions, 1 deletions

diff --git a/protocol/src/main/java/org/apache/drill/exec/proto/beans/QueryType.java b/protocol/src/main/java/org/apache/drill/exec/proto/beans/QueryType.java
index 71f98f37c..7a4320d48 100644
--- a/protocol/src/main/java/org/apache/drill/exec/proto/beans/QueryType.java
+++ b/protocol/src/main/java/org/apache/drill/exec/proto/beans/QueryType.java
@@ -25,7 +25,8 @@ public enum QueryType implements com.dyuproject.protostuff.EnumLite<QueryType>
     SQL(1),
     LOGICAL(2),
     PHYSICAL(3),
-    EXECUTION(4);
+    EXECUTION(4),
+    PREPARED_STATEMENT(5);
     
     public final int number;
     
@@ -47,6 +48,7 @@ public enum QueryType implements com.dyuproject.protostuff.EnumLite<QueryType>
             case 2: return LOGICAL;
             case 3: return PHYSICAL;
             case 4: return EXECUTION;
+            case 5: return PREPARED_STATEMENT;
             default: return null;
         }
     }