Aula 7 - 28.09.2010 - Classes Java

Menu.java

---

package br.edu.metodista.acesso.menu;

public class Menu {

   private Long id;
   private String nome;

   public Long getId() { return id; }
   public void setId(Long id) { this.id = id; }

   public String getNome() { return nome; }
   public void setNome(String nome) {       this.nome = nome; }

   @Override
   public boolean equals(Object obj) {
      if (obj == null) {
         return false;
      }
      if (getClass() != obj.getClass()) {
         return false;
      }
      final Menu other = (Menu) obj;
      if (this.id != other.id && (this.id == null || !this.id.equals(other.id))) {
         return false;
      }
      return true;
   }

   @Override
   public int hashCode() {
      int hash = 7;
      hash = 83 * hash + (this.id != null ? this.id.hashCode() : 0);
      return hash;
   }

   @Override
   public String toString() {
      return nome;
   }
}

MenuDAO.java

---

package br.edu.metodista.acesso.menu;

import java.sql.*;
import java.util.*;
import br.edu.metodista.ipa.bd.*;

public class MenuDAO {

   public int salvar(Menu menu) throws Exception {
      if (existe(menu))
         return alterar(menu);
      else
         return incluir(menu);
   }

   public int incluir(Menu menu) throws Exception {
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(INCLUIR_SQL);
      try {
         stmt.setLong(1, BD.getProximoId(TABELA));
         stmt.setString(2, menu.getNome());
         return stmt.executeUpdate();
      } finally {
         stmt.close();
         conn.close();
      }
   }

   public int alterar(Menu menu) throws Exception {
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(ALTERAR_SQL);
      try {
         stmt.setLong(1, menu.getId());
         stmt.setString(2, menu.getNome());
         stmt.setLong(3, menu.getId());
         return stmt.executeUpdate();
      } finally {
         stmt.close();
         conn.close();
      }
   }

   public int excluir(Menu menu) throws Exception {
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(EXCLUIR_SQL);
      try {
         stmt.setLong(1, menu.getId());
         return stmt.executeUpdate();
      } finally {
         stmt.close();
         conn.close();
      }
   }

   public boolean existe(Menu menu) throws Exception {
      if (menu.getId() == null)
         return false;
      
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(EXISTE_SQL);
      try {
         stmt.setLong(1, menu.getId());
         RecordSet rs = new RecordSet(stmt.executeQuery());
         if (rs.next())
            return true;
         return false;
      } finally {
         stmt.close();
         conn.close();
      }
   }

   public boolean carregar(Menu menu) throws Exception {
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(CARREGAR_SQL);
      try {
         stmt.setLong(1, menu.getId());
         RecordSet rs = new RecordSet(stmt.executeQuery());
         if (rs.next()) {
            menu.setNome(rs.getString("nome"));
            return true;
         }
         return false;
      } finally {
         stmt.close();
         conn.close();
      }
   }

   public ArrayList listar() throws Exception {
      ArrayList lista = new ArrayList();
      Connection conn = BD.getConnection();
      PreparedStatement stmt = conn.prepareStatement(LISTAR_SQL);
      try {
         RecordSet rs = new RecordSet(stmt.executeQuery());
         while (rs.next()) {
            Menu menu = new Menu();
            menu.setId(rs.getLong("id"));
            menu.setNome(rs.getString("nome"));
         }
         return lista;
      } finally {
         stmt.close();
         conn.close();
      }
   }

   private static final String TABELA = "tbl_menu";
   private static final String INCLUIR_SQL  = "INSERT INTO " + TABELA + " (id, nome) VALUES (?,?)";
   private static final String ALTERAR_SQL  = "UPDATE " + TABELA + " SET id=?, nome=? WHERE id=?";
   private static final String EXCLUIR_SQL  = "DELETE FROM " + TABELA + " WHERE id=?";
   private static final String CARREGAR_SQL = "SELECT * FROM " + TABELA + " WHERE id=?";
   private static final String EXISTE_SQL   = "SELECT id FROM " + TABELA + " WHERE id=?";
   private static final String LISTAR_SQL   = "SELECT * FROM " + TABELA + " ";

   public static void main(String[] args) throws Exception {
      Menu s = null;

      s = new Menu();
      s.setNome("Países");
      new MenuDAO().salvar(s);

      s = new Menu();
      s.setNome("Estados");
      new MenuDAO().salvar(s);

      s = new Menu();
      s.setNome("Cidades");
      new MenuDAO().salvar(s);
   }
}