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- /*
- @VaadinApache2LicenseForJavaFiles@
- */
- package com.vaadin.data.util.sqlcontainer.connection;
-
- import java.io.IOException;
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.SQLException;
- import java.sql.Statement;
- import java.util.HashSet;
- import java.util.Set;
-
- /**
- * Simple implementation of the JDBCConnectionPool interface. Handles loading
- * the JDBC driver, setting up the connections and ensuring they are still
- * usable upon release.
- */
- @SuppressWarnings("serial")
- public class SimpleJDBCConnectionPool implements JDBCConnectionPool {
-
- private int initialConnections = 5;
- private int maxConnections = 20;
-
- private String driverName;
- private String connectionUri;
- private String userName;
- private String password;
-
- private transient Set<Connection> availableConnections;
- private transient Set<Connection> reservedConnections;
-
- private boolean initialized;
-
- public SimpleJDBCConnectionPool(String driverName, String connectionUri,
- String userName, String password) throws SQLException {
- if (driverName == null) {
- throw new IllegalArgumentException(
- "JDBC driver class name must be given.");
- }
- if (connectionUri == null) {
- throw new IllegalArgumentException(
- "Database connection URI must be given.");
- }
- if (userName == null) {
- throw new IllegalArgumentException(
- "Database username must be given.");
- }
- if (password == null) {
- throw new IllegalArgumentException(
- "Database password must be given.");
- }
- this.driverName = driverName;
- this.connectionUri = connectionUri;
- this.userName = userName;
- this.password = password;
-
- /* Initialize JDBC driver */
- try {
- Class.forName(driverName).newInstance();
- } catch (Exception ex) {
- throw new RuntimeException("Specified JDBC Driver: " + driverName
- + " - initialization failed.", ex);
- }
- }
-
- public SimpleJDBCConnectionPool(String driverName, String connectionUri,
- String userName, String password, int initialConnections,
- int maxConnections) throws SQLException {
- this(driverName, connectionUri, userName, password);
- this.initialConnections = initialConnections;
- this.maxConnections = maxConnections;
- }
-
- private void initializeConnections() throws SQLException {
- availableConnections = new HashSet<Connection>(initialConnections);
- reservedConnections = new HashSet<Connection>(initialConnections);
- for (int i = 0; i < initialConnections; i++) {
- availableConnections.add(createConnection());
- }
- initialized = true;
- }
-
- @Override
- public synchronized Connection reserveConnection() throws SQLException {
- if (!initialized) {
- initializeConnections();
- }
- if (availableConnections.isEmpty()) {
- if (reservedConnections.size() < maxConnections) {
- availableConnections.add(createConnection());
- } else {
- throw new SQLException("Connection limit has been reached.");
- }
- }
-
- Connection c = availableConnections.iterator().next();
- availableConnections.remove(c);
- reservedConnections.add(c);
-
- return c;
- }
-
- @Override
- public synchronized void releaseConnection(Connection conn) {
- if (conn == null || !initialized) {
- return;
- }
- /* Try to roll back if necessary */
- try {
- if (!conn.getAutoCommit()) {
- conn.rollback();
- }
- } catch (SQLException e) {
- /* Roll back failed, close and discard connection */
- try {
- conn.close();
- } catch (SQLException e1) {
- /* Nothing needs to be done */
- }
- reservedConnections.remove(conn);
- return;
- }
- reservedConnections.remove(conn);
- availableConnections.add(conn);
- }
-
- private Connection createConnection() throws SQLException {
- Connection c = DriverManager.getConnection(connectionUri, userName,
- password);
- c.setAutoCommit(false);
- if (driverName.toLowerCase().contains("mysql")) {
- try {
- Statement s = c.createStatement();
- s.execute("SET SESSION sql_mode = 'ANSI'");
- s.close();
- } catch (Exception e) {
- // Failed to set ansi mode; continue
- }
- }
- return c;
- }
-
- @Override
- public void destroy() {
- for (Connection c : availableConnections) {
- try {
- c.close();
- } catch (SQLException e) {
- // No need to do anything
- }
- }
- for (Connection c : reservedConnections) {
- try {
- c.close();
- } catch (SQLException e) {
- // No need to do anything
- }
- }
-
- }
-
- private void writeObject(java.io.ObjectOutputStream out) throws IOException {
- initialized = false;
- out.defaultWriteObject();
- }
-
- }
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