Hi Just some thoughts. You could use the delegate pattern instead of inheritence. This will help decouple your FormBeans from your DaoBeans.
Keith -----Original Message----- From: Struts Newsgroup [mailto:@[EMAIL PROTECTED]] Sent: Thursday, 24 January 2002 9:10 a.m. To: [EMAIL PROTECTED] Subject: Re: Model Persistence Survey Subject: Re: Model Persistence Survey From: Vic Cekvenich <[EMAIL PROTECTED]> === Here is a sample DAO Extended Form Bean code : public class NameZoomFrm extends daoFormBean { private String fstName; private String lstName; public String getFstName() { //get it from _crs RowSet CachedRowSet cr = getCrs(); try{ this.fstName = cr.getString("first_name"); } // try catch (Exception e) {System.out.println(e);} // catch return (this.fstName); }// get public String getLstName() { //get it from _crs RowSet CachedRowSet cr = getCrs(); try{ this.lstName = cr.getString("last_name"); } // try catch (Exception e) {System.out.println(e);} // catch return (this.lstName); }// get public void setFstName(String aFstName) { //get it from _crs RowSet CachedRowSet cr = getCrs(); try{ cr.updateString("first_name",aFstName); this.fstName = aFstName; } // try catch (Exception e) {System.out.println(e);} // catch setCrs(cr); } //setFst public void setLstName(String aLstName) { //get it from _crs RowSet CachedRowSet cr = getCrs(); try{ cr.updateString("last_name",aLstName); this.lstName=aLstName; } // try catch (Exception e) {System.out.println(e);} // catch setCrs(cr); } //setFst public int retrieve(BigDecimal aBD) { try{ CachedRowSet cr = getCrs(); cr = new CachedRowSet(); // easier then resultset // you must test this sql string manualy for a SQL IDE cr.setCommand("select * from contact where id = ?"); // driver issues fix: cr.setTableName("contact"); // to limit the number of rows coming back, we only need a page at a time cr.setBigDecimal(1,aBD); exec(cr); } // try catch (Exception e) { System.out.println(e); e.printStackTrace();} // catch return 0; }// retrieve public void blank() { try { CachedRowSet cr = getCrs(); cr.updateNull("first_name"); cr.updateNull("last_name"); cr.updateNull("id"); } catch (Exception e) { procE(this,e);} // catch }// blank }//class Here is the DAO implementation ... using RowSet, but could use JDO, such as Castor. import com.wintecinc.struts.action.ValidatorForm; public class daoFormBean extends ValidatorForm { private Connection con=null; private Connection upCon=null; private DataSource ds; private CachedRowSet _crs; private String sqlString; private BigDecimal PK; public Connection getCon() {return con;} public CachedRowSet getCrs() {return this._crs;} public void setCrs(CachedRowSet aCRS) {this._crs=aCRS;} public Hashtable getIterateMap() { //is there a better way? like use crs.getCollection? CachedRowSet cr = getCrs(); int rc=cr.size(); Hashtable iterateMap = new Hashtable(); // count out the number of rows with dummy map for (int i=1; i <= rc; i++) { iterateMap.put(new Integer(i),new Integer(i));} return iterateMap;} public BigDecimal getPK() { //get it from _crs RowSet try{ this.PK = _crs.getBigDecimal("id"); } // try catch (Exception e) {System.out.println(e);} // catch return (this.PK); }// get public void dbCon() { // connect to db try{ ds = PoolMan.findDataSource("jndiSample"); //we should in production give it a password in code not in file pool.xml con=ds.getConnection();} catch (Exception e) { debug(this, "We did not connect"); procE(this,e);} // catch }// con public void dbDisCon() { try{if (con!=null) con.close(); ds=null; } catch (Exception e) {System.out.println(e); }//catch } //disCon public int getRowNext() { // get the next row try{ CachedRowSet cr = getCrs(); cr.next(); } catch (Exception e) { debug(this,"what row"); System.out.println(e); e.printStackTrace();} // catch return 0; } // rowNext() public long update(){ try{ // update should be using a different con pool to same db dbCon(); _crs.updateRow(); _crs.acceptChanges(getCon()); dbDisCon(); } catch (Exception e) { procE(this,e);} // catch return 0; } // update() should return new PK public void setDelete() { // mark this row deleted CachedRowSet cr = getCrs(); try{ cr.updateString("DEL_FLG","X"); // send to DB update(); } // try catch (Exception e) {System.out.println(e);} // catch } //del public void newRow() { try { debug(this," Insert begin"); dbCon(); BigDecimal tmp = new BigDecimal(1); retreive(tmp); // descemdat SQL Row signature CachedRowSet cr = getCrs(); cr.moveToInsertRow(); blank(); debug(this," before InsertRow"); cr.insertRow(); cr.moveToCurrentRow(); cr.next(); debug(this," we HAVE set up an insert"); } catch (Exception e) { debug(this, "oh no new row, check driver"); e.printStackTrace(); procE(this,e);} // catch } // newRow() public void blank() { } // stub public int retrieve(BigDecimal aBD) { System.out.println("should never be called"); return 0;} // stub // implement in descendent public void setSqlString(String aSQL) { sqlString = aSQL;} public daoFormBean() { // cons super(); try{ _crs = new CachedRowSet(); } // try catch (Exception e) { System.out.println(e); e.printStackTrace();} } //cons public int exec(CachedRowSet pCR) { int c=0; try{ pCR.execute(getCon()); pCR.first(); c= pCR.size(); //debug(this,c+" rc "+pCR.getCommand()); setCrs(pCR); }// try catch (Exception e) {procE(this,e); } // catch return c; } // exec }//class And to call above in perform: public ActionForward perform( ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { NameZoomFrm frm = (NameZoomFrm) form; if (frm == null) {frm = new NameZoomFrm();} String PK = request.getParameter("PK"); String parameter = mapping.getParameter(); if (parameter == null) parameter ="X"; if (parameter.equals("del")) { BigDecimal pkBD = new BigDecimal (PK); frm.setDelete(); return(mapping.findForward("searchNam")); } else if (PK != null) { // do we have an argument PK passed? Display! BigDecimal pkBD = new BigDecimal (PK); frm.dbCon(); frm.retrieve(pkBD); frm.dbDisCon(); } else if (parameter.equals("new")) { frm.newRow(); } else { // Save ActionErrors errors = frm.validate(mapping,request); if (!errors.empty()) { saveErrors(request, errors); return (new ActionForward(mapping.getInput()));} frm.update(); // save the cached row to DB return(mapping.findForward("searchNam")); } // else return(mapping.findForward("nameZoomPg")); // go to search pg. }// perform Act } // class Ted Husted wrote: > If anyone has any brief code examples or other notes to share regarding > how they handle the interface between ActionForm beans and their model > beans, I'd be happy to compile something for the Users Guide. > > -- Ted Husted, Husted dot Com, Fairport NY USA. > -- Java Web Development with Struts. > -- Tel +1 585 737-3463. > -- Web http://www.husted.com/struts/ > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
