Java Ultra-Lite Persistence (JULP)

Tips and Tricks

• If you want to use TIMESTAMP or DATETIME or version column for Optimistic concurrency locking you can use this trick:
  JULP supposed to automatically retrieve PrimaryKey info from DataBaseMetaData, and you can add your TIMESTAMP/DATETIME/version column to PrimaryKey info and this column will be used for creating WHERE clause for UPDATE and DELETE:
  
  CREATE TABLE PRODUCT(ID INTEGER NOT NULL PRIMARY KEY,NAME VARCHAR,PRICE DECIMAL, ..., TIMESTAMP DATE_MODIFIED)
...
String catalog;
String schema;
String table = "PRODUCT";
List pk;
...
pk = PKCache.getInstance().getPrimaryKey(catalog, schema, table);
pk.add("PRODUCT.DATE_MODIFIED");
PKCache.getInstance().setPrimaryKey(catalog, schema, table, pk);
...
factory.remove(product);
...
Generated SQL would be: DELETE FROM PRODUCT WHERE ID = ? AND DATE_MODIFIED = ?;
  Note: retrieving PrimaryKey info from java.sql.DatabaseMetaData occurred once per JVM instance in DomainObjectFactory.load() or DomainObjectFactory.writeData(), so if those methods never called, the info is unavailable. However you can call
  PKCache.getInstance().getPrimaryKey(catalog, schema, table);
  or
  PKCache.getInstance().setPrimaryKey(catalog, schema, table);
  
• Normally to make your object able to persist you need to extend org.julp.AbstractDomainObject class. If you can't or don't want to extend, just make your class implement org.julp.DomainObject interface and copy and paste members and methods from org.julp.AbstractDomainObject into your class. Otherwise object will be enchanced in run-time using CGLIB/ASM libraries.
• To make field non-persistent just use metaData.setReadOnly(metaData.getColumnIndexByFieldName(fieldName), true);