org.opensubsystems.core.persist.db
Class DatabaseReadMultipleOperation

java.lang.Object
  org.opensubsystems.core.persist.db.DatabaseOperation
      org.opensubsystems.core.persist.db.DatabaseReadOperation
          org.opensubsystems.core.persist.db.DatabaseReadMultipleOperation

All Implemented Interfaces:

DatabaseOperations

public abstract class DatabaseReadMultipleOperation
extends DatabaseReadOperation

Adapter to simplify writing of database reads which read multiple items, which takes care of requesting and returning connections, transaction management, query preparation and exception handling. To use this adapter you just need to define anonymous class and override method performOperation to provide the actual database read. Optionally you may want to override one of the handleXXX methods to provide custom error handling. This class is optimized for preparing queries, which need to retrieve multiple items from the database. Example of method in factory which reads data using query produced by its schema public int[] getActualIds( final int iDomainId, String strIds, SimpleRule listSecurityData ) throws OSSException { int[] arrActual = null; DatabaseReadOperation dbop = new DatabaseReadMultipleOperation( this, m_schema.getSelectActualIds(strIds, listSecurityData), m_schema, dataType) { protected Object performOperation( DatabaseFactoryImpl dbfactory, Connection cntConnection, PreparedStatement pstmQuery ) throws OSSException, SQLException { pstmQuery.setInt(1, iDomainId); return DatabaseUtils.loadMultipleIntsAsArray(pstmQuery); } }; arrActual = (int[])dbop.executeRead(); return arrActual; }

Version:

$Id: DatabaseReadMultipleOperation.java,v 1.7 2007/01/28 06:54:42 bastafidli Exp $

Author:

Miro Halas

Code reviewer:

Miro Halas

Code reviewed:

1.2 2005/10/25 05:17:37 bastafidli

Field Summary

Fields inherited from class org.opensubsystems.core.persist.db.DatabaseOperation

m_data, m_dbschema, m_factory, m_iDataType, m_returnData, m_strQuery

Fields inherited from interface org.opensubsystems.core.persist.db.DatabaseOperations

DBOP_DELETE, DBOP_INSERT, DBOP_SELECT, DBOP_UPDATE

Constructor Summary

DatabaseReadMultipleOperation(DatabaseFactoryImpl factory)
Constructor to use when the database read doesn't require any prepared statement.

DatabaseReadMultipleOperation(DatabaseFactoryImpl factory, java.lang.String strQueryToPrepare, DatabaseSchema schema)
Constructor to use when database read doesn't require any prepared statement.

Method Summary

protected java.sql.PreparedStatement

prepareQuery(DatabaseFactoryImpl dbfactory, java.sql.Connection cntConnection, java.lang.String strQuery) Prepare the query if it was specified using the provided connection.

Methods inherited from class org.opensubsystems.core.persist.db.DatabaseReadOperation

executeRead, handleKnownError, handleSQLException, handleUnknownError, performOperation

Methods inherited from class org.opensubsystems.core.persist.db.DatabaseOperation

getReturnData, setReturnData

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DatabaseReadMultipleOperation

public DatabaseReadMultipleOperation(DatabaseFactoryImpl factory)

Constructor to use when the database read doesn't require any prepared statement.

Parameters:

factory - - factory which is executing this operation

DatabaseReadMultipleOperation

public DatabaseReadMultipleOperation(DatabaseFactoryImpl factory,
                                     java.lang.String strQueryToPrepare,
                                     DatabaseSchema schema)

Constructor to use when database read doesn't require any prepared statement.

Parameters:

factory - - factory which is executing this operation

strQueryToPrepare - - query which should be used to construct prepared statement which will be passed in to executeUpdate

schema - - database schema used with this operation

Method Detail

prepareQuery

protected java.sql.PreparedStatement prepareQuery(DatabaseFactoryImpl dbfactory,
                                                  java.sql.Connection cntConnection,
                                                  java.lang.String strQuery)
                                           throws OSSException,
                                                  java.sql.SQLException

Prepare the query if it was specified using the provided connection.

Overrides:

prepareQuery in class DatabaseReadOperation

Parameters:

dbfactory - - database factory executing this operation

cntConnection - - ready to use connection to perform the database operation. No need to return this connection.

strQuery - - query to prepare, might be null or empty if there is nothing to prepare

Returns:

PreparedStatement - prepared statement for query passed in as a parameter to the constructor. If no query was passed into constructor, this will be null.

Throws:

OSSException - - an error has occured

java.sql.SQLException - - an error has occured