albumaction.java

the musiccollection struts 1 application i netbeans implementation (strut for dummies book source)

package dummies.struts.music;

import java.util.ArrayList;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.util.ModuleException;
import org.apache.struts.validator.DynaValidatorForm;

/**
 * @author Mike Robinson
 *
 */
public class AlbumAction extends Action 
{
	Log log = LogFactory.getLog(AlbumAction.class);	// commons logging reference
	
	/**
	 * Handles request from user
	 * @param mapping
	 * @param form
	 * @param request
	 * @param response
	 * @throws Exception
	 */
	public ActionForward execute( 	ActionMapping mapping,
									ActionForm form,
									HttpServletRequest request,
									HttpServletResponse response)
									throws Exception
	{
		
		// deterine the action. values can be null, 'save', 'update', or 'cancel'
		String action = (String)((DynaValidatorForm)form).get("action1");
		// action2 can be either null, empty or contain 'view' or 'delete'
		String action2 = (String) request.getParameter("action2");	// comes from musiclist
		if(action2!=null)
			if(!action2.equals(""))
				action = action2;	// replace action with action2 if action2 is not empty
		if((action == null)|(action.equals(""))) 	// request came from musiclist to create an Album
		{
			ServletContext sc = this.getServlet().getServletContext();
			((DynaValidatorForm)form).set("years",(ArrayList)sc.getAttribute("years"));
			((DynaValidatorForm)form).set("types",(ArrayList)sc.getAttribute("types"));
			((DynaValidatorForm)form).set("categories",(ArrayList)sc.getAttribute("categories"));
			return (mapping.findForward("new"));
		}
		else if(action.equalsIgnoreCase("view"))	// request came from musiclist to edit an Album
		{
			// get the id of the album
			int id = convertID((String) request.getParameter("id"));
			if(id > 0)
			{
				// create a new AlbumBean passing the datasource
				AlbumBean ab = new AlbumBean(getDataSource(request, "musiccollection"));
				AlbumDTO album = ab.findAlbum(id);
				ServletContext sc = this.getServlet().getServletContext();
				xferToForm(album,form,sc);				
			}
			return (mapping.findForward("new"));
		}
		else if(action.equalsIgnoreCase("delete"))	// request came from musiclist to delete an Album
		{
			// get the id of the album
			int id = convertID((String) request.getParameter("id"));
			if(id > 0)
			{
				// create a new AlbumBean passing the datasource
				AlbumBean ab = new AlbumBean(getDataSource(request, "musiccollection"));
				ab.deleteAlbum(id);
			}
		}
		else if (action.equalsIgnoreCase("cancel"))	// request to abandon adding/modifying an album
		{
			return(mapping.findForward("cancel"));
		}
		else if ((action.equalsIgnoreCase("save"))|(action.equalsIgnoreCase("update")))
		{
			ActionErrors errors = ((DynaValidatorForm)form).validate(mapping,request);
			if(errors.isEmpty())
			{
				// get the session object
				HttpSession session = request.getSession();
				// get the user object
				UserDTO user = (UserDTO)session.getAttribute("user");
				// initialize a fresh AlbumDTO
				AlbumDTO album = new AlbumDTO();
				// move form info to album
				xferToBean(form,album,action,user);
				// create a new AlbumBean passing the datasource
				AlbumBean ab = new AlbumBean(getDataSource(request, "musiccollection"));
				// if action == save, insert the new album
				if(action.equalsIgnoreCase("save"))
					ab.saveAlbum(album);
				else	// must need to update existing album
					ab.updateAlbum(album);
			}
			else	// there were validation errors
			{
				ServletContext sc = this.getServlet().getServletContext();
				((DynaValidatorForm)form).set("years",(ArrayList)sc.getAttribute("years"));
				((DynaValidatorForm)form).set("types",(ArrayList)sc.getAttribute("types"));
				((DynaValidatorForm)form).set("categories",(ArrayList)sc.getAttribute("categories"));
				saveErrors(request, errors);
				return (mapping.findForward("failure"));
			}
		}
		return (mapping.findForward("success"));				
	}
	
	/**
	 * transfer bean data to form
	 * @param album
	 * @param form
	 */
	private void xferToForm(AlbumDTO album, ActionForm form, ServletContext sc)
	{
		((DynaValidatorForm)form).set("album",album.getAlbum());
		((DynaValidatorForm)form).set("artist",album.getArtist());
		((DynaValidatorForm)form).set("description",album.getDescription());
		((DynaValidatorForm)form).set("year",album.getYear());
		((DynaValidatorForm)form).set("category",album.getCategory());
		((DynaValidatorForm)form).set("type",album.getType());
		((DynaValidatorForm)form).set("id",String.valueOf(album.getId()));
		((DynaValidatorForm)form).set("userid",String.valueOf(album.getUserid()));
		((DynaValidatorForm)form).set("years",(ArrayList)sc.getAttribute("years"));
		((DynaValidatorForm)form).set("types",(ArrayList)sc.getAttribute("types"));
		((DynaValidatorForm)form).set("categories",(ArrayList)sc.getAttribute("categories"));

	}
	
	/**
	 * transfer data from form to bean
	 * @param form
	 * @param album
	 * @param action
	 * @param user
	 * @throws ModuleException
	 */
	private void xferToBean(ActionForm form, AlbumDTO album, String action, UserDTO user) throws ModuleException
	{
		album.setAlbum((String)((DynaValidatorForm)form).get("album"));
		album.setArtist((String)((DynaValidatorForm)form).get("artist"));
		album.setDescription((String)((DynaValidatorForm)form).get("description"));
		album.setYear((String)((DynaValidatorForm)form).get("year"));
		album.setType((String)((DynaValidatorForm)form).get("type"));
		album.setCategory((String)((DynaValidatorForm)form).get("category"));
		if(action.equalsIgnoreCase("update"))
		{
			try
			{
				album.setUserid(Integer.parseInt((String)((DynaValidatorForm)form).get("userid")));
				album.setId(Integer.parseInt((String)((DynaValidatorForm)form).get("id")));
			}
			catch(NumberFormatException nfe)
			{
				log.error("error in converting string to a number");
				log.error(nfe.getLocalizedMessage());
				ModuleException me = new ModuleException("error.nfe.message");
				throw me;			
			}
		}
		else	// assume creating a new album, so no userID or ID available in form
		{
			album.setUserid(user.getId());
			album.setId(0);
		}
	}
	
	/**
	 * convert String id to numeric
	 * @param id
	 * @return int
	 * @throws ModuleException
	 */
	private int convertID(String id) throws ModuleException
	{
		int idNum = 0;
		if(id != null)	// id should contain the id of the album to delete
			if(!id.equals(""))	// then user is request to delete an album
		{
			// convert the String id to int id
			try
			{
				idNum = Integer.parseInt(id);
			}
			catch(NumberFormatException nfe)
			{
				log.error("error in converting string to a number");
				log.error(nfe.getLocalizedMessage());
				ModuleException me = new ModuleException("error.nfe.message");
				throw me;			
			}
		}
		return idNum;
	}
}