Wrap queries in a transaction with rollback

If a tweet cannot be processed, then it must be faulty. Do not fill the
database with useless information.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/main/DataFiller.java b/src/main/DataFiller.java
index 803d926..71f1822 100644
--- a/src/main/DataFiller.java
+++ b/src/main/DataFiller.java
@@ -44,6 +44,8 @@ public class DataFiller {
         m_insertTweetUrl = new NamedPreparedStatement(m_connection, QueryUtils.insertTweetUrl);
         m_insertUserUrl = new NamedPreparedStatement(m_connection, QueryUtils.insertUserUrl);
         m_insertMentions = new NamedPreparedStatement(m_connection, QueryUtils.insertMentions);
+        // enable transactions
+        connection.setAutoCommit(false);
     }
 
     /**
@@ -68,6 +70,18 @@ public class DataFiller {
             processTweet(tweet.retweeted_status);
         }
 
+        try {
+            // assume that no previous transaction was started.
+            saveTweet(tweet);
+            // concludes the previous query, implicitly starts a new transaction
+            m_connection.commit();
+        } catch (Exception ex) {
+            m_connection.rollback();
+            throw ex;
+        }
+    }
+
+    private void saveTweet(Tweet tweet) throws SQLException {
         String text = sanitizeTweetText(tweet.text);
         // ensure that the user and tweet are known before adding relations
         QueryUtils.setInsertParams(m_insertTweet, m_insertProfile, tweet, text);