struts与ajax设计

/* * StoryDAO.java * * Created on August 24, 2002, 7:01 PM */ package com.apress.javaedge.story.dao; import com.apress.javaedge.common.*; import com.apress.javaedge.story.StoryVO; import org.apache.commons.logging.Log; import org.apache.ojb.broker.PersistenceBroker; import org.apache.ojb.broker.PersistenceBrokerException; import org.apache.ojb.broker.metadata.DescriptorRepository; import org.apache.ojb.broker.metadata.ClassDescriptor; import org.apache.ojb.broker.query.Criteria; import org.apache.ojb.broker.query.Query; import org.apache.ojb.broker.query.QueryByCriteria; import org.apache.ojb.broker.query.QueryFactory; import java.util.Collection; import java.util.Iterator; /** * * StoryDAO is responsible for all CRUD logic associated with stories. * */ public class StoryDAO implements DataAccessObject { public static final int MAXIMUM_TOPSTORIES = 11; /** * Commons Log for this class */ private static Log log = ServiceLocator.getInstance().getLog(StoryDAO.class); /** * Finds a single Story record by a story id passed into the method. * @see com.apress.javaedge.common.DataAccessObject#findByPK(java.lang.String) */ public ValueObject findByPK(String primaryKey) throws DataAccessException { log.debug("************Entering the StoryDAO.findByPK***************"); PersistenceBroker broker = null; StoryVO storyVO = null; try { broker = ServiceLocator.getInstance().findBroker(); storyVO = new StoryVO(); storyVO.setStoryId(new Long(primaryKey)); Query query = new QueryByCriteria(storyVO); storyVO = (StoryVO) broker.getObjectByQuery(query); } catch (ServiceLocatorException e) { log.error("PersistenceBrokerException thrown in StoryDAO.findByPK()", e); throw new DataAccessException("Error in StoryDAO.findByPK(): " + e.toString(), e); } finally { if (broker != null) broker.close(); } log.debug("************Done with the StoryDAO.findByPK()***************"); return storyVO; } /** * Returns a collection of the top latest stories. The number of records to * be returned are controlled by the MAXIMUM_TOPSTORIES constant on this * class. * @return Collection * @throws DataAccessException */ public Collection findTopStory() throws DataAccessException { log.debug("************Entering with the StoryDAO.findTopStory()***************"); PersistenceBroker broker = null; Collection results = null; Criteria criteria = new Criteria(); criteria.addOrderByDescending("storyId"); Query query = QueryFactory.newQuery(StoryVO.class, criteria); query.setStartAtIndex(0); query.setEndAtIndex(MAXIMUM_TOPSTORIES); try { broker = ServiceLocator.getInstance().findBroker(); DescriptorRepository descriptorRepository = broker.getDescriptorRepository(); Iterator iterator = descriptorRepository.iterator(); log.debug("--------------------------------------"); while (iterator.hasNext()){ ClassDescriptor classDescriptor = (ClassDescriptor) iterator.next(); log.debug("Class Name: " + classDescriptor.getClassNameOfObject()); log.debug("Table Name: " + classDescriptor.getFullTableName()); } log.debug(descriptorRepository); log.debug("--------------------------------------"); results = (Collection) broker.getCollectionByQuery(query); } catch (ServiceLocatorException e) { log.error("PersistenceBrokerException thrown in StoryDAO.findTopStory()", e); throw new DataAccessException("Error in StoryDAO.findTopStory(): " + e.toString(), e); } finally { if (broker != null) broker.close(); } log.debug("************Done with the StoryDAO.findTopStory()***************"); return results; } /** * Inserts a single story record into the database. * * @see com.apress.javaedge.common.DataAccessObject#insert(com.apress.javaedge.common.ValueObject) */ public void insert(ValueObject insertRecord) throws DataAccessException { log.debug("************Entering the StoryDAO.insert()***************"); PersistenceBroker broker = null; try { StoryVO storyVO = (StoryVO) insertRecord; broker = ServiceLocator.getInstance().findBroker(); broker.beginTransaction(); broker.store(storyVO); broker.commitTransaction(); } catch (PersistenceBrokerException e) { // if something went wrong: rollback broker.abortTransaction(); log.error("PersistenceBrokerException thrown in StoryDAO.insert()", e); throw new DataAccessException("Error in StoryDAO.insert(): " + e.toString(), e); } catch (ServiceLocatorException e) { log.error("ServiceLocatorException thrown in StoryDAO.insert()", e); throw new DataAccessException("ServiceLocatorException thrown in StoryDAO.insert()", e); } finally { if (broker != null) broker.close(); } log.debug("************Done with the StoryDAO.insert()***************"); } /** * Deletes a single record from the story table using OJB. */ public void delete(ValueObject deleteRecord) throws DataAccessException { log.debug("************Entering the StoryDAO.delete()***************"); PersistenceBroker broker = null; try { broker = ServiceLocator.getInstance().findBroker(); StoryVO storyVO = (StoryVO) deleteRecord; //Begin the transaction. broker.beginTransaction(); broker.delete(storyVO); broker.commitTransaction(); } catch (PersistenceBrokerException e) { // if something went wrong: rollback broker.abortTransaction(); log.error("PersistenceBrokerException thrown in StoryDAO.delete()", e); throw new DataAccessException("Error in StoryDAO.delete()", e); } catch (ServiceLocatorException e) { throw new DataAccessException("ServiceLocator exception in StoryDAO.delete()", e); } finally { if (broker != null) broker.close(); } log.debug("************Done with the StoryDAO.delete()***************"); } /** * Updates a single record from the story table using OJB. */ public void update(ValueObject updateRecord) throws DataAccessException { log.debug("************Entering the StoryDAO.update()***************"); PersistenceBroker broker = null; try { StoryVO storyVO = (StoryVO) updateRecord; broker = ServiceLocator.getInstance().findBroker(); broker.beginTransaction(); broker.store(storyVO); broker.commitTransaction(); } catch (PersistenceBrokerException e) { // if something went wrong: rollback broker.abortTransaction(); log.error("PersistenceBrokerException thrown in StoryDAO.update()", e); throw new DataAccessException("Error in StoryDAO.update()", e); } catch (ServiceLocatorException e) { log.error("ServiceLocatorException thrown in StoryDAO.delete()", e); throw new DataAccessException("ServiceLocatorException error in StoryDAO.delete()", e); } finally { if (broker != null) broker.close(); } log.debug("************Done with the StoryDAO.updat