Java(TM) Boutique - Using DAOs in Apache Struts

Tutorials : Using DAOs in Apache Struts :

The SimpleDVDManager

Our first implementation of this interface will be a manager that stores the DVDs in a HashMap. This implementation will only be used for testing so we'll not persist the data. When the manager is loaded we'll create and store two example DVDs in the HashMap:

package dk.hansen;

import java.util.*;

public class SimpleDVDManager implements DVDManagerIF {

  private static HashMap dvds = new HashMap();

  static {
    // Create two DVDs for testing
    String id; DVD dvd;
    id = "ID10";
    dvd = new DVD(id, "Troy");
    dvds.put(id, dvd);
    id = "ID11";
    dvd = new DVD(id, "Peter Pan");
    dvds.put(id, dvd);
  }

  public void createDVD(String id, String title) throws DAOException {
    DVD dvd = (DVD)dvds.get(id);
    if (dvd != null) throw new DAOException("Id " + id + " is already used");
    dvd = new DVD(id, title);
    dvds.put(id, dvd);
  }

  public void updateDVD(String id, String title) throws DAOException {
    DVD dvd = (DVD)dvds.get(id);
    if (dvd == null) throw new DAOException("Id " + id + " was not found");
    dvd.setTitle(title);
  }

  public void deleteDVD(String id) throws DAOException {
    DVD dvd = (DVD)dvds.get(id);
    if (dvd == null) throw new DAOException("Id " + id + " was not found");
    dvds.remove(id);
  }

  public DVD getDVD(String id) {
    DVD dvd = (DVD)dvds.get(id);
    return dvd;
  }

  public Collection getAll() {
    return dvds.values();
  }

  public Collection findDVDTitle(String title) {
    Collection hits = new ArrayList(); 
    Collection c = dvds.values();
    for (Iterator it = c.iterator(); it.hasNext();) {
      DVD dvd = (DVD)it.next();
      if (dvd.getTitle().toUpperCase().indexOf(title.toUpperCase()) > -1) {
        hits.add(dvd);
      }
    }
    return hits;
  }
}

The create, update and delete methods may throw an exception, as specified in table 1.

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