Adds Pet DAO

It connects the SQL pets queries to Java Entities

src/main/java/es/uvigo/esei/daa/dao/PetDAO.java

+package es.uvigo.esei.daa.dao;
+
+import es.uvigo.esei.daa.entities.Pet;
+
+import java.sql.*;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * DAO class for the {@link Pet} entities.
+ *
+ * @author albovy
+ *
+ */
+public class PetDAO extends DAO{
+    private final static Logger LOG  = Logger.getLogger(PetDAO.class.getName());
+
+    /**
+     * Returns a pet stored persisted in the system.
+     *
+     * @param id identifier of the pet.
+     * @return a pet with the provided identifier.
+     * @throws DAOException if an error happens while retrieving the person.
+     * @throws IllegalArgumentException if the provided if does not corresponds with any persisted person.
+     *
+     */
+    public Pet get(int id) throws DAOException, IllegalArgumentException{
+        try(final Connection conn = this.getConnection()){
+            final String query = "SELECT * FROM pets WHERE id=?";
+
+            try(final PreparedStatement statement = conn.prepareStatement(query)){
+                statement.setInt(1,id);
+
+                try(final ResultSet result = statement.executeQuery()){
+                    if(result.next()){
+                        return rowToEntity(result);
+                    }else{
+                        throw new IllegalArgumentException("Invalid id");
+                    }
+                }
+            }
+
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE,"Error getting a pet", e);
+            throw new DAOException(e);
+        }
+
+    }
+    /**
+     * Returns a list with all the pets persisted in the system.
+     *
+     * @return a list with all the pets persisted in the system.
+     * @throws DAOException if an error happens while retrieving the people.
+     */
+    public List<Pet> list()throws DAOException{
+        try (final Connection conn = this.getConnection()){
+            final String query = "SELECT * FROM pets";
+
+            try(final PreparedStatement statement = conn.prepareStatement(query)){
+                try(final ResultSet result = statement.executeQuery()){
+                    final List<Pet> pets = new LinkedList<>();
+
+                    while (result.next()){
+                        pets.add(rowToEntity(result));
+                    }
+
+                    return pets;
+                }
+            }
+
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE,"Error listing pets");
+            throw new DAOException(e);
+        }
+    }
+
+    /**
+     * Returns a list with all pets persisted in the system from a person.
+     *
+     * @param idPeople identifier of the person. Can't be {@code null}
+     * @return a list with all pets persisted in the system from a person.
+     * @throws DAOException if an error happens while retrieving the pets.
+     * @throws IllegalArgumentException if the idPeople are {@code null}.
+     */
+
+    public List<Pet> listForPeople(Integer idPeople) throws DAOException,IllegalArgumentException{
+        if(idPeople == null){
+            throw new IllegalArgumentException("idPeople can't be null");
+        }
+
+        try(final Connection conn = this.getConnection()){
+            final String query = "SELECT * FROM pets WHERE person=?";
+
+            try(final PreparedStatement statement = conn.prepareStatement(query)){
+                statement.setInt(1,idPeople);
+
+                try(final ResultSet result = statement.executeQuery()){
+                    final List<Pet> pets = new LinkedList<>();
+
+                    while (result.next()){
+                        pets.add(rowToEntity(result));
+                    }
+
+                    return pets;
+                }
+            }
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE,"Error listing pets with idPeople",e);
+            throw new DAOException(e);
+        }
+    }
+    /**
+     * Persists a new pet in the system. An identifier will be assigned
+     * automatically to the new person.
+     *
+     * @param name name of the new pet. Can't be {@code null}.
+     * @param type specie of the new pet. Can't be {@code null}.
+     * @param person owner of the pet. Can't be {@code null}.
+     * @return a {@link Pet} entity representing the persisted pet.
+     * @throws DAOException if an error happens while persisting the new pet.
+     * @throws IllegalArgumentException if the name or type or person are {@code null}.
+     *
+     */
+    public Pet add(String name,String type,Integer person) throws DAOException,IllegalArgumentException{
+        if(name == null || type == null || person == null){
+            throw new IllegalArgumentException("name, type and person can't be null");
+        }
+        try(Connection conn = this.getConnection()){
+            final String query = "INSERT INTO pets VALUES(null,?,?,?)";
+
+            try(PreparedStatement statement = conn.prepareStatement(query, Statement.RETURN_GENERATED_KEYS)){
+                statement.setString(1,name);
+                statement.setString(2,type);
+                statement.setInt(3, person);
+
+                if(statement.executeUpdate() == 1){
+                    try(ResultSet resultKeys = statement.getGeneratedKeys()){
+                        if(resultKeys.next()){
+                            return new Pet(resultKeys.getInt(1),name,type,person);
+                        }else{
+                            LOG.log(Level.SEVERE,"Error retrieving inserted id");
+                            throw new SQLException("Error retrieving inserted id");
+                        }
+                    }
+                }else{
+                    LOG.log(Level.SEVERE,"Error inserting a value");
+                    throw new SQLException("Error inserting value");
+                }
+            }
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE, "Error adding a person",e);
+            throw new DAOException(e);
+        }
+    }
+
+    /**
+     * Modifies a pet previously persisted in the system. The pet wil be
+     * retrieved by the provided id and its current name, type and person will be
+     * replaced with the provided.
+     *
+     * @param pet a {@link Pet} entity with the new data.
+     * @throws DAOException if an error happens while modifying the new pet.
+     * @throws IllegalArgumentException if the pet is {@code null}.
+     *
+     */
+    public void modify(Pet pet) throws DAOException,IllegalArgumentException{
+        if(pet == null){
+            throw new IllegalArgumentException("Pet can't be null");
+        }
+
+        try(Connection conn = this.getConnection()){
+            final String query = "UPDATE pets SET name=?, type=?, person=? WHERE id=?";
+
+            try(PreparedStatement statement = conn.prepareStatement(query)){
+                statement.setString(1,pet.getName());
+                statement.setString(2,pet.getType());
+                statement.setInt(3,pet.getPerson());
+                statement.setInt(4,pet.getId());
+
+                if(statement.executeUpdate() != 1){
+                    throw new IllegalArgumentException("Name, type and person can't be null");
+                }
+            }
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE, "Error modifying a pet",e);
+            throw new DAOException();
+        }
+    }
+    /**
+     * Removes a persisted pet from the system.
+     *
+     * @param id identifier of the pet to be deleted.
+     * @throws DAOException if an error happens while deleting the person.
+     * @throws IllegalArgumentException if the provided if does not corresponds
+     * with any persisted person.
+     */
+    public void delete(int id) throws  DAOException, IllegalArgumentException{
+        try(final Connection conn = this.getConnection()){
+            final String query = "DELETE FROM pets WHERE id=?";
+
+            try(final PreparedStatement statement = conn.prepareStatement(query)){
+                statement.setInt(1,id);
+
+                if(statement.executeUpdate() != 1){
+                    throw new IllegalArgumentException("Invalid id");
+                }
+            }
+        }catch (SQLException e){
+            LOG.log(Level.SEVERE,"Error deleting a pet",e);
+            throw new DAOException(e);
+        }
+    }
+
+    private Pet rowToEntity(ResultSet row) throws  SQLException{
+        return new Pet(
+                row.getInt("id"),
+                row.getString("name"),
+                row.getString("type"),
+                row.getInt("person")
+        );
+    }
+}
+