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src/main/java/tools/DatabaseConnection.java

@@ -0,0 +1,97 @@
+package tools;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+
+import config.YamlConfig;
+
+/**
+ * @author Frz (Big Daddy)
+ * @author The Real Spookster - some modifications to this beautiful code
+ * @author Ronan - some connection pool to this beautiful code
+ */
+public class DatabaseConnection {
+    private static HikariDataSource ds;
+    
+    public static Connection getConnection() throws SQLException {
+        if(ds != null) {
+            try {
+                return ds.getConnection();
+            } catch (SQLException sqle) {
+                sqle.printStackTrace();
+            }
+        }
+        
+        int denies = 0;
+        while(true) {   // There is no way it can pass with a null out of here?
+            try {
+                return DriverManager.getConnection(YamlConfig.config.server.DB_URL, YamlConfig.config.server.DB_USER, YamlConfig.config.server.DB_PASS);
+            } catch (SQLException sqle) {
+                denies++;
+                
+                if(denies == 3) {
+                    // Give up, throw exception. Nothing good will come from this.
+                    FilePrinter.printError(FilePrinter.SQL_EXCEPTION, "SQL Driver refused to give a connection after " + denies + " tries. Problem: " + sqle.getMessage());
+                    throw sqle;
+                }
+            }
+        }
+    }
+    
+    private static int getNumberOfAccounts() {
+        try {
+            Connection con = DriverManager.getConnection(YamlConfig.config.server.DB_URL, YamlConfig.config.server.DB_USER, YamlConfig.config.server.DB_PASS);
+            try (PreparedStatement ps = con.prepareStatement("SELECT count(*) FROM accounts")) {
+                try (ResultSet rs = ps.executeQuery()) {
+                    rs.next();
+                    return rs.getInt(1);
+                }
+            } finally {
+                con.close();
+            }
+        } catch(SQLException sqle) {
+            return 20;
+        }
+    }
+    
+    public DatabaseConnection() {
+        try {
+            Class.forName("com.mysql.jdbc.Driver"); // touch the mysql driver
+        } catch (ClassNotFoundException e) {
+            System.out.println("[SEVERE] SQL Driver Not Found. Consider death by clams.");
+            e.printStackTrace();
+        }
+        
+        ds = null;
+        
+        if(YamlConfig.config.server.DB_CONNECTION_POOL) {
+            // Connection Pool on database ftw!
+            
+            HikariConfig config = new HikariConfig();
+            config.setJdbcUrl(YamlConfig.config.server.DB_URL);
+            
+            config.setUsername(YamlConfig.config.server.DB_USER);
+            config.setPassword(YamlConfig.config.server.DB_PASS);
+            
+            // Make sure pool size is comfortable for the worst case scenario.
+            // Under 100 accounts? Make it 10. Over 10000 accounts? Make it 30.
+            int poolSize = (int)Math.ceil(0.00202020202 * getNumberOfAccounts() + 9.797979798);
+            if(poolSize < 10) poolSize = 10;
+            else if(poolSize > 30) poolSize = 30;
+            
+            config.setConnectionTimeout(30 * 1000);
+            config.setMaximumPoolSize(poolSize);
+            
+            config.addDataSourceProperty("cachePrepStmts", true);
+            config.addDataSourceProperty("prepStmtCacheSize", 25);
+            config.addDataSourceProperty("prepStmtCacheSqlLimit", 2048);
+
+            ds = new HikariDataSource(config);
+        }
+    }
+}