--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/nabble/model/SystemProperties.java	Thu Mar 21 19:15:52 2019 -0600
@@ -0,0 +1,120 @@
+package nabble.model;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Holds a Map with strings.
+ * Basically, this is used to persist keys and values used by the application.
+ * The cache Map is just a copy of the system table in the database.
+ *
+ * @author Hugo Teixeira
+ */
+public class SystemProperties {
+
+	private static final Logger logger = LoggerFactory.getLogger(SystemProperties.class);
+
+	private static final Map<String, String> cache = new TreeMap<String, String>();
+
+	static {
+		load();
+	}
+
+	private static void load() {
+		long start = System.currentTimeMillis();
+		try {
+			Connection con = Db.dbGlobal().getConnection();
+			try {
+				PreparedStatement stmt = con.prepareStatement("select * from system");
+				ResultSet rs = stmt.executeQuery();
+				while (rs.next()) {
+					String key = rs.getString("key_");
+					String value = rs.getString("value");
+					cache.put(key, value);
+				}
+			} finally {
+				con.close();
+			}
+			logger.info("System properties loaded in " + (System.currentTimeMillis() - start) + " ms");
+		} catch(SQLException e) {
+			logger.error(SystemProperties.class.toString(), e);
+		}
+	}
+
+	public static synchronized void set(String key, String value) {
+		try {
+			Connection con = Db.dbGlobal().getConnection();
+			try {
+				if (cache.containsKey(key)) {
+					PreparedStatement stmt = con.prepareStatement("update system set value=? where key_=?");
+					stmt.setString(1, value);
+					stmt.setString(2, key);
+					stmt.execute();
+					stmt.close();
+				} else {
+					PreparedStatement stmt = con.prepareStatement("insert into system values (?,?)");
+					stmt.setString(1, key);
+					stmt.setString(2, value);
+					stmt.execute();
+					stmt.close();
+				}
+			} finally {
+				con.close();
+			}
+			cache.put(key, value);
+			logger.info("System Property added: " + key + " -- " + value);
+		} catch(SQLException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	public synchronized static String get(String key) {
+		return cache.get(key);
+	}
+
+	public synchronized static int size() {
+		return cache.size();
+	}
+
+	public synchronized static void remove(String key) {
+		try {
+			String sql = "delete from system where key_='" + key + "';";
+			Connection con = Db.dbGlobal().getConnection();
+			try {
+				PreparedStatement stmt = con.prepareStatement(sql);
+				stmt.execute();
+			} finally {
+				con.close();
+			}
+			cache.remove(key);
+			logger.info("System Properties -- Key Removed = " + key);
+		} catch(SQLException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	public synchronized static void clear() {
+		try {
+			String sql = "delete from system";
+			Connection con = Db.dbGlobal().getConnection();
+			try {
+				PreparedStatement stmt = con.prepareStatement(sql);
+				stmt.execute();
+			} finally {
+				con.close();
+			}
+			cache.clear();
+			logger.info("System Properties cleared");
+		} catch(SQLException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+}