110 lines
3.4 KiB
Java
110 lines
3.4 KiB
Java
package de.dis2017.data.db;
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import de.dis2017.data.EstateAgent;
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import java.sql.*;
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import java.util.HashMap;
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import java.util.Map;
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/**
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* Maps the data objects to the database and vice versa.
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*/
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public class ORM {
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private Connection _connection;
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private Map<Integer, EstateAgent> _agents;
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/**
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* Initializes the ORM.
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*/
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public ORM() {
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DB2ConnectionManager _dbManager = DB2ConnectionManager.getInstance();
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_connection = _dbManager.getConnection();
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_agents = new HashMap<>();
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}
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/**
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* Loads the estate agent with the given ID from database and returns the corresponding object.
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*
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* @param ID the ID of the agent to load
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* @return returns the EstateAgent or null if there is no such agent
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*/
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public EstateAgent get(int ID) {
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if (_agents.containsKey(ID)) {
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return _agents.get(ID);
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}
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try {
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// create query
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String selectSQL = "SELECT * FROM ESTATEAGENT WHERE ID = ?";
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PreparedStatement pstmt = _connection.prepareStatement(selectSQL);
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pstmt.setInt(1, ID);
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// execute query
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ResultSet rs = pstmt.executeQuery();
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EstateAgent agent;
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if (rs.next()) {
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agent = new EstateAgent();
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agent.setId(ID);
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agent.setName(rs.getString("name"));
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agent.setAddress(rs.getString("address"));
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agent.setLogin(rs.getString("login"));
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agent.setPassword(rs.getString("password"));
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rs.close();
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pstmt.close();
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_agents.put(ID, agent);
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return agent;
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}
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} catch (SQLException e) {
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e.printStackTrace();
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}
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return null;
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}
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/**
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* Persists the given agent.
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*
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* @param agent the agent that should be persisted
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*/
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public void persist(EstateAgent agent)
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{
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try {
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if (agent.getId() == -1) {
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String insertSQL = "INSERT INTO ESTATEAGENT (name, address, login, password) VALUES (?, ?, ?, ?)";
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PreparedStatement pstmt = _connection.prepareStatement(insertSQL, Statement.RETURN_GENERATED_KEYS);
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pstmt.setString(1, agent.getName());
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pstmt.setString(2, agent.getAddress());
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pstmt.setString(3, agent.getLogin());
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pstmt.setString(4, agent.getPassword());
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pstmt.executeUpdate();
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ResultSet rs = pstmt.getGeneratedKeys();
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if (rs.next()) {
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agent.setId(rs.getInt(1));
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}
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rs.close();
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pstmt.close();
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} else {
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// create query
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String updateSQL = "UPDATE ESTATEAGENT SET name = ?, address = ?, password = ? WHERE ID = ?";
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PreparedStatement pstmt = _connection.prepareStatement(updateSQL);
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pstmt.setString(1, agent.getName());
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pstmt.setString(2, agent.getAddress());
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pstmt.setString(3, agent.getPassword());
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pstmt.setInt(4, agent.getId());
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// execute query
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pstmt.executeUpdate();
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pstmt.close();
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}
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} catch (SQLException e) {
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e.printStackTrace();
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}
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}
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}
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