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Look-up Tables: DAO components

6 July 2008
Author: Restamon Posted under Code

Now that we have the tests set up for the look-up table data access object, it’s time to create the actual data access object. In continuing my approach of modeling my components off of those found in the AppFuse Light collection, I used the UserDaoHibernate module as the basis of my own LookupTableDaoHibernate class. Of course, in AppFuse Light, UserDaoHibernate implements interface UserDao which extends the Dao interface, so I started at the beginning:

package org.restafarian.core.dao;

/**
 * Data Access Object (Dao) interface. This is an empty interface
 * used to tag our Dao classes. Common methods for each interface
 * could be added here.
 */
public interface Dao {
}

There’s virtually no difference between this one and the original, but I strayed just a little bit off of the pattern on the LookupTableDao interface, because I wanted to add a couple of additional ways to get to the data:

package org.restafarian.core.dao;

import java.util.List;

import org.restafarian.core.beans.LookupTable;

/**
 * <p>This is the LookupTable data access object interface.</p>
 */
public interface LookupTableDao extends Dao {

  /**
   * <p>Returns all LookupTables in the database.</p>
   *
   * @return all LookupTables in the database
   */
    public List findAll();

  /**
   * <p>Returns all LookupTables in the database that
   * match the specified search criteria.</p>
   *
   * @param lookupTable an example LookupTable
   * @return all LookupTables in the database that
   * match the specified search criteria
   */
  public List findByExample(LookupTable lookupTable);

  /**
   * <p>Returns all LookupTables in the database that
   * match the specified search criteria.</p>
   *
   * @param propertyName the name of the specified property
   * @param propertyValue the search value for the specified
   * property
   * @return all LookupTables in the database that
   * match the specified search criteria
   */
  public List findByProperty(String propertyName, Object propertyValue);

  /**
   * <p>Returns the LookupTable with the specified id.</p>
   *
   * @param id the id of the requested lookupTable
   * @return the LookupTable with the specified id
   */
    public LookupTable findById(String LookupTableId);

  /**
   * <p>Saves the LookupTable passed.</p>
   *
   * @param lookupTable the lookupTable to save
   */
    public void save(LookupTable LookupTable);

  /**
   * <p>Deletes the LookupTable with the specified id.</p>
   *
   * @param id the id of the lookupTable to delete
   */
    public void delete(String LookupTableId);
}

That just leaves the Hibernate implementation, which again, pretty much follows the original with the addition of the extra data access methods:

package org.restafarian.core.dao.hibernate;

import java.util.List;

import org.restafarian.core.beans.LookupTable;
import org.restafarian.core.dao.LookupTableDao;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

/**
 * <p>This is the LookupTable data access object.</p>
 */
public class LookupTableDaoHibernate extends HibernateDaoSupport implements LookupTableDao {

  /**
   * <p>Returns all LookupTables in the database.</p>
   *
   * @return all LookupTables in the database
   */
  public List findAll() {
    return getHibernateTemplate().find("from LookupTable order by id");
  }

  /**
   * <p>Returns all LookupTables in the database that
   * match the specified search criteria.</p>
   *
   * @param lookupTable an example LookupTable
   * @return all LookupTables in the database that
   * match the specified search criteria
   */
  public List findByExample(LookupTable lookupTable) {
    return getHibernateTemplate().findByExample(lookupTable);
  }

  /**
   * <p>Returns all LookupTables in the database that
   * match the specified search criteria.</p>
   *
   * @param propertyName the name of the specified property
   * @param propertyValue the search value for the specified
   * property
   * @return all LookupTables in the database that
   * match the specified search criteria
   */
  public List findByProperty(String propertyName, Object propertyValue) {
    StringBuffer buffer = new StringBuffer();
    buffer.append("from LookupTable where ");
    buffer.append(propertyName);
    buffer.append(" = '");
    buffer.append(propertyValue);
    buffer.append("' order by id");
    return getHibernateTemplate().find(buffer.toString());
  }

  /**
   * <p>Returns the LookupTable with the specified id.</p>
   *
   * @param id the id of the requested lookupTable
   * @return the LookupTable with the specified id
   */
  public LookupTable findById(String id) {
    LookupTable lookupTable = (LookupTable) getHibernateTemplate().get(LookupTable.class, id);
    if (lookupTable == null) {
      throw new ObjectRetrievalFailureException(LookupTable.class, id);
    }
    return lookupTable;
  }

  /**
   * <p>Saves the LookupTable passed.</p>
   *
   * @param lookupTable the lookupTable to save
   */
  public void save(LookupTable lookupTable) {
    getHibernateTemplate().saveOrUpdate(lookupTable);
  }

  /**
   * <p>Deletes the LookupTable with the specified id.</p>
   *
   * @param id the id of the lookupTable to delete
   */
  public void delete(String id) {
    getHibernateTemplate().delete(findById(id));
  }
}

That pretty much completes the Dao and all of its related parts, but before we can actually pull the trigger on the tests, we still have a little work to do in order to configure this all up via Spring. That will be the subject of our next installment.


http://blog.restafarian.org/2008/07/look-up-tables-dao-components/

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