Adding logic to the batabase upgrade.

1. Introduced a new db table "db_version_history" to hal-default.db. The table contains a list of db version. Every version has some parameters:
- 'db-version' (int) - A db version number. table 'conf', key 'db_version' points to this.
- 'force-upgrade' (default:0) - If 1 then force the upgrade to this version
- 'clear-internal-aggr-data' (default:0) - If 1 then clear all internal aggr data before upgrade.
- 'clear-external-aggr-data' (defualt:0) - If 1 then clear all external aggr data before upgrade.
The db table 'conf', key 'db_version' has to point to the db version to upgrad to. Only forward upgrades are supported.

2. Modified HalContext to act accoring to the parameters in the new db table.


Former-commit-id: 19bd87ade3129f3fc0c51f0e1b94f71dc854d792

src/se/koc/hal/HalContext.java

@@ -2,6 +2,7 @@ package se.koc.hal;
 
 import zutil.db.DBConnection;
 import zutil.db.DBUpgradeHandler;
+import zutil.db.SQLResultHandler;
 import zutil.db.handler.PropertiesSQLResult;
 import zutil.io.file.FileUtil;
 import zutil.log.LogUtil;
@@ -9,7 +10,9 @@ import zutil.log.LogUtil;
 import java.io.File;
 import java.io.FileReader;
 import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.sql.Statement;
 import java.util.Properties;
 import java.util.logging.Logger;
 
@@ -77,8 +80,35 @@ public class HalContext {
                 logger.fine(String.format("Upgrading DB (from: v%s, to: v%s)...", dbVersion, defaultDBVersion));
                 DBUpgradeHandler handler = new DBUpgradeHandler(referenceDB);
                 handler.setTargetDB(db);
-                //handler.setForcedDBUpgrade(true);
+                
+                //read upgrade path preferences from the reference database
+                referenceDB.exec("SELECT * FROM db_version_history"
+                		+ " WHERE db_version <= " + defaultDBVersion
+                		+ " AND db_version > " + dbVersion, 
+                		new SQLResultHandler<Object>() {
+					@Override
+					public Object handleQueryResult(Statement stmt, ResultSet result) throws SQLException {
+						while(result.next()){
+							if(result.getBoolean("force_upgrade")){ 
+								handler.setForcedDBUpgrade(true);	//set to true if any of the intermediate db version requires it.
+							}
+							if(result.getBoolean("clear_external_aggr_data")){
+								db.exec("DELETE FROM sensor_data_aggr WHERE sensor_id = "
+										+ "(SELECT sensor_id FROM user, sensor WHERE user.external == 1 AND sensor.user_id = user.id)");
+							}
+							if(result.getBoolean("clear_internal_aggr_data")){
+								db.exec("DELETE FROM sensor_data_aggr WHERE sensor_id = "
+										+ "(SELECT sensor_id FROM user, sensor WHERE user.external == 0 AND sensor.user_id = user.id)");
+							}
+						}
+						return null;
+					}
+				});
+                
                 handler.upgrade();
+                
+                //remove table from target database. this table is supposed to only be put in the reference db.
+                db.exec("DROP TABLE db_version_history");
 
                 logger.info("DB upgrade done");
                 dbConf.setProperty(PROPERTY_DB_VERSION, defaultDBConf.getProperty(PROPERTY_DB_VERSION));