dailyseqidgenerator.java

采用tapestry的简单OA系统

package com.ejsun.entapps.domain.util;

import java.util.Date;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;

import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Session;
import net.sf.hibernate.SessionFactory;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.InitializingBean;

import com.ejsun.entapps.domain.SequenceIdGenerator;
import com.ejsun.entapps.util.FormatConstants;

/**
 * DailySeqIdGenerator that returns a Sequence Id, constructed by counting from the today maximum value.
 * The return format is 'yyyy-MM-dd-xxxxx'. 
 * @author	Quake Wang
 * @since	2004-5-19
 * @version $Revision: 1.2 $
 * 
 **/
public class DailySeqIdGenerator implements InitializingBean, SequenceIdGenerator {
    private static final Log log = LogFactory.getLog(DailySeqIdGenerator.class);
	private static final long FORMATER = 100000;
	
    private SessionFactory sessionFactory;
    private Map sequences;
    private Map maxSeqIds;

    public void afterPropertiesSet() throws Exception {
        maxSeqIds = new Hashtable();
        if (sequences == null)
            return;

        Session session = sessionFactory.openSession();
        String today = formatToday();
        try {
            for (Iterator iter = sequences.keySet().iterator(); iter.hasNext();) {
                String className = (String) iter.next();
                String seqName = (String) sequences.get(className);
                Iterator results =
                    session.iterate(
                        "select max(clazz."
                            + seqName
                            + ") from "
                            + className
                            + " clazz where clazz."
                            + seqName
                            + " like '"
                            + today
                            + "%'");
                if (results.hasNext()) {
					String maxValue = (String) results.next();
                	if(maxValue != null) {
						log.info("Got max value " + className + "." + seqName + " : " + maxValue);
						maxSeqIds.put(className + today, new Long(maxValue.substring(11)));                		
                	}
                }
            }
        } catch (HibernateException he) {
            throw he;
        } finally {
            if (session != null)
                session.close();
        }
    }

    public String getSequenceId(Class clazz) {
        String today = formatToday();
        String key = clazz.getName() + today;
        Long result = null;
        Long maxSeqId = (Long) maxSeqIds.get(key);
        synchronized (DailySeqIdGenerator.class) {
            if (maxSeqId != null) {
                result = new Long(maxSeqId.longValue() + 1);
            } else {
                result = new Long(1);
            }
        }
        maxSeqIds.put(key, result);       
        return today + Long.toString(result.longValue() + FORMATER).substring(1);
    }

	private String formatToday() {
		return FormatConstants.DATE_FORMAT.format(new Date()) + "-";
	}


    public void setSequences(Map map) {
        sequences = map;
    }

    public void setSessionFactory(SessionFactory factory) {
        sessionFactory = factory;
    }

}