Mega Code Archive
Manage Db connections providing shortcuts for Statements, PreparedStatements and ResultSets
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/*
* Copyright © 2009 Perseus Project - Tufts University <http://www.perseus.tufts.edu>
*
* This file is part of DbUtilPerseus.
*
* DbUtilPerseus is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* DbUtilPerseus is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with DbUtilPerseus. If not, see <http://www.gnu.org/licenses/>.
*/
//package eu.himeros.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
/**
* Manage Db connections providing shortcuts for Statements, PreparedStatements
* and ResultSets.
*
* @author Federico Boschetti <federico.boschetti.73@gmail.com>
*/
public class DbManager {
public Connection con;
public Statement stmt;
public PreparedStatement pstmt;
public ResultSet rst;
public Statement[] stmts;
public PreparedStatement[] pstmts;
public ResultSet[] rsts;
private String driverName;
private String dbName;
private boolean dbArray;
private int stmtsSize;
private int pstmtsSize;
private int rstsSize;
/**
* Initialize a generic DbManager.
*
* @param driver
* the driver.
* @param database
* the database name.
* @param login
* the login.
* @param passwd
* the password.
*/
public DbManager(String driver, String database, String login, String passwd) {
dbArray = false;
try {
initDb(driver, database, login, passwd);
stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Initialize the DbManager, using hsqldb defaults.
*/
public DbManager() {
dbArray = false;
try {
initDb("hsqldb", ".", "sa", "");
stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Initialize the DbManager.
*
* @param driver
* the driver.
* @param database
* the database name.
* @param login
* the login.
* @param passwd
* the password.
* @param stmtsSize
* the max number of Statement instances.
* @param pstmtsSize
* the max number of PreparedStatement instances.
* @param rstsSize
* the max number of ResultSet instances.
*/
public void dbManager(String driver, String database, String login,
String passwd, int stmtsSize, int pstmtsSize, int rstsSize) {
dbArray = true;
this.stmtsSize = stmtsSize;
this.pstmtsSize = pstmtsSize;
this.rstsSize = rstsSize;
try {
initDb(driver, database, login, passwd);
if (stmtsSize > 0) {
stmts = new Statement[stmtsSize];
for (int i = 0; i < stmtsSize; i++) {
stmts[i] = con.createStatement(
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
}
}
if (pstmtsSize > 0) {
pstmts = new PreparedStatement[pstmtsSize];
}
if (rstsSize != 0) {
rsts = new ResultSet[rstsSize];
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Initialize the DbManager.
*
* @param driver
* the driver.
* @param database
* the database name.
* @param login
* the login.
* @param passwd
* the password.
* @param stmtsSize
* the max number of Statement instances.
* @param pstmtsSize
* the max number of PreparedStatement instances.
* @param rstsSize
* the max number of ResultSet instances.
*/
public DbManager(String driver, String database, String login,
String passwd, int stmtsSize, int pstmtsSize, int rstsSize) {
dbManager(driver, database, login, passwd, stmtsSize, pstmtsSize,
rstsSize);
}
/**
* Initialize the DbManager.
*
* @param driver
* the driver.
* @param database
* the database name.
* @param login
* the login.
* @param passwd
* the password.
* @param stmtsSize
* the max number of Statement instances.
* @param rstsSize
* the max number of ResultSet instances.
*/
public DbManager(String driver, String database, String login,
String passwd, int stmtsSize, int rstsSize) {
dbManager(driver, database, login, passwd, stmtsSize, 0, rstsSize);
}
/**
* Provide the PreparedStatement, given a query.
*
* @param query
* the query.
* @return the PreparedStatement based on the query.
*/
public PreparedStatement prepareStatement(String query) {
try {
pstmt = con.prepareStatement(query,
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
return pstmt;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* Shortcut for hsqldb driver name.
*
* @param driver
* the driver.
* @param database
* the database name.
*/
private void longNames(String driver, String database) {
if (driver.equals("hsqldb")) {
driverName = "org.hsqldb.jdbcDriver";
dbName = "jdbc:hsqldb:" + database;
} else {
driverName = driver;
dbName = database;
}
}
/**
* Initialize the database.
*
* @param driver
* the driver.
* @param database
* the database name.
* @param login
* the login.
* @param passwd
* the password.
*/
private void initDb(String driver, String database, String login,
String passwd) {
try {
longNames(driver, database);
Class.forName(driverName);
con = DriverManager.getConnection(dbName, login, passwd);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Close the single instance of ResultSet, PreparedStatement, Statement and
* Connection.
*/
private void closeSingle() {
try {
if (rst != null) {
rst.close();
}
if (pstmt != null) {
pstmt.close();
}
stmt.close();
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Close the array.
*/
private void closeArray() {
try {
for (int i = 0; i < rstsSize; i++) {
if (rsts[i] != null) {
rsts[i].close();
}
}
for (int i = 0; i < stmtsSize; i++) {
if (stmts[i] != null) {
stmts[i].close();
}
}
for (int i = 0; i < pstmtsSize; i++) {
if (pstmts[i] != null) {
pstmts[i].close();
}
}
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Close the array or the single instance.
*/
public void close() {
if (dbArray) {
closeArray();
} else {
closeSingle();
}
}
/**
* Close the ResultSet
*
* @param rst
* the ResultSet
*/
public void close(ResultSet rst) {
try {
rst.close();
closeSingle();
} catch (Exception e) {
e.printStackTrace();
}
}
}
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