diff --git a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/DeviceManagementDAOFactory.java b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/DeviceManagementDAOFactory.java index 7c86387ee4..8d28f17825 100644 --- a/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/DeviceManagementDAOFactory.java +++ b/components/device-mgt/org.wso2.carbon.device.mgt.core/src/main/java/org/wso2/carbon/device/mgt/core/dao/DeviceManagementDAOFactory.java @@ -32,6 +32,52 @@ import java.sql.SQLException; import java.util.Hashtable; import java.util.List; +/** + * This class intends to act as the primary entity that hides all DAO instantiation related complexities and logic so + * that the business objection handling layer doesn't need to be aware of the same providing seamless plug-ability of + * different data sources, connection acquisition mechanisms as well as different forms of DAO implementations to the + * high-level implementations that require device management related metadata persistence. + *
+ * In addition, this also provides means to handle transactions across multiple device management related DAO objects. + * Any high-level business logic that requires transaction handling to be done via utility methods provided in + * DeviceManagementDAOFactory should adhere the following guidelines to avoid any unexpected behaviour that can cause + * as a result of improper use of the aforementioned utility method. + * + * Any transaction that commits data into the underlying data persistence mechanism MUST follow the sequence of + * operations mentioned below. + * + *+ * {@code + * try { + * DeviceManagementDAOFactory.beginTransaction(); + * ..... + * DeviceManagementDAOFactory.commitTransaction(); + * return success; + * } catch (Exception e) { + * DeviceManagementDAOFactory.rollbackTransaction(); + * throw new DeviceManagementException("Error occurred while ...", e); + * } finally { + * DeviceManagementDAOFactory.closeConnection(); + * } + * } + *+ * + * Any transaction that retrieves data from the underlying data persistence mechanism MUST follow the sequence of + * operations mentioned below. + * + *
+ * {@code + * try { + * DeviceManagementDAOFactory.openConnection(); + * ..... + * } catch (Exception e) { + * throw new DeviceManagementException("Error occurred while ..., e); + * } finally { + * DeviceManagementDAOFactory.closeConnection(); + * } + * } + *+ */ public class DeviceManagementDAOFactory { private static DataSource dataSource;