From e2778fbf7d81b10fa558deeb9ccf66d374de7f4f Mon Sep 17 00:00:00 2001
From: Gary Tully <gtully@apache.org>
Date: Wed, 24 Jun 2009 12:04:50 +0000
Subject: [PATCH] apply modified suggstion from
 https://issues.apache.org/activemq/browse/AMQ-1191 - executeQuery conditional
 on statement metadata which works when statement does not return a result set
 like with derby which is used in the unit tests

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@787990 13f79535-47bb-0310-9956-ffa450edef68
---
 .../activemq/store/jdbc/DefaultDatabaseLocker.java     | 10 +++++++++-
 .../store/jdbc/adapter/DefaultJDBCAdapter.java         |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/activemq-core/src/main/java/org/apache/activemq/store/jdbc/DefaultDatabaseLocker.java b/activemq-core/src/main/java/org/apache/activemq/store/jdbc/DefaultDatabaseLocker.java
index dd6b359ea8..906067a1a8 100644
--- a/activemq-core/src/main/java/org/apache/activemq/store/jdbc/DefaultDatabaseLocker.java
+++ b/activemq-core/src/main/java/org/apache/activemq/store/jdbc/DefaultDatabaseLocker.java
@@ -19,6 +19,8 @@ package org.apache.activemq.store.jdbc;
 import java.io.IOException;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 
 import javax.sql.DataSource;
@@ -64,7 +66,13 @@ public class DefaultDatabaseLocker implements DatabaseLocker {
                 connection.setAutoCommit(false);
                 String sql = statements.getLockCreateStatement();
                 statement = connection.prepareStatement(sql);
-                statement.execute();
+                if (statement.getMetaData() != null) {
+                    ResultSet rs = statement.executeQuery();
+                    // if not already locked the statement below blocks until lock acquired
+                    rs.next();
+                } else {
+                    statement.execute();
+                }
                 break;
             } catch (Exception e) {
                 if (stopping) {
diff --git a/activemq-core/src/main/java/org/apache/activemq/store/jdbc/adapter/DefaultJDBCAdapter.java b/activemq-core/src/main/java/org/apache/activemq/store/jdbc/adapter/DefaultJDBCAdapter.java
index e1682d00b0..8df17e716a 100755
--- a/activemq-core/src/main/java/org/apache/activemq/store/jdbc/adapter/DefaultJDBCAdapter.java
+++ b/activemq-core/src/main/java/org/apache/activemq/store/jdbc/adapter/DefaultJDBCAdapter.java
@@ -291,7 +291,7 @@ public class DefaultJDBCAdapter implements JDBCAdapter {
                 throw new SQLException("Failed to remove message");
             }
         } finally {
-            if (!this.batchStatments) {
+            if (!this.batchStatments && s != null) {
                 s.close();
             }
         }