public PooledDataSource(
ClassLoader driverClassLoader, String driver, String url, Properties driverProperties) {
dataSource = new UnpooledDataSource(driverClassLoader, driver, url, driverProperties);
expectedConnectionTypeCode =
assembleConnectionTypeCode(
dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
}
public static UnpooledDataSource createUnpooledDataSource(String resource) throws IOException {
Properties props = Resources.getResourceAsProperties(resource);
UnpooledDataSource ds = new UnpooledDataSource();
ds.setDriver(props.getProperty("driver"));
ds.setUrl(props.getProperty("url"));
ds.setUsername(props.getProperty("username"));
ds.setPassword(props.getProperty("password"));
return ds;
}
/*
* Closes all active and idle connections in the pool
*/
public void forceCloseAll() { // 关闭pool里的所有连接，两个list中的连接都移除且关闭
synchronized (state) {
expectedConnectionTypeCode =
assembleConnectionTypeCode(
dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
for (int i = state.activeConnections.size(); i > 0; i--) { // 遍历活动连接list
try {
PooledConnection conn = state.activeConnections.remove(i - 1); // 从活动连接list移出
conn.invalidate(); // PooledConnection的valid设为false
Connection realConn = conn.getRealConnection(); // 获取真conn (java.sql.Connection)
if (!realConn.getAutoCommit()) { // 不是自动提交的话
realConn.rollback(); // 回滚
}
realConn.close();
} catch (Exception e) {
// ignore
}
}
for (int i = state.idleConnections.size(); i > 0; i--) { // 简历空闲连接list
try {
PooledConnection conn = state.idleConnections.remove(i - 1);
conn.invalidate();
Connection realConn = conn.getRealConnection();
if (!realConn.getAutoCommit()) {
realConn.rollback();
}
realConn.close();
} catch (Exception e) {
// ignore
}
}
}
if (log.isDebugEnabled()) {
log.debug("PooledDataSource forcefully closed/removed all connections.");
}
}
/*
* Closes all active and idle connections in the pool
*/
public void forceCloseAll() {
synchronized (state) {
expectedConnectionTypeCode =
assembleConnectionTypeCode(
dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
for (int i = state.activeConnections.size(); i > 0; i--) {
try {
PooledConnection conn = (PooledConnection) state.activeConnections.remove(i - 1);
conn.invalidate();
Connection realConn = conn.getRealConnection();
if (!realConn.getAutoCommit()) {
realConn.rollback();
}
realConn.close();
} catch (Exception e) {
// ignore
}
}
for (int i = state.idleConnections.size(); i > 0; i--) {
try {
PooledConnection conn = (PooledConnection) state.idleConnections.remove(i - 1);
conn.invalidate();
Connection realConn = conn.getRealConnection();
if (!realConn.getAutoCommit()) {
realConn.rollback();
}
realConn.close();
} catch (Exception e) {
// ignore
}
}
}
if (log.isDebugEnabled()) {
log.debug("PooledDataSource forcefully closed/removed all connections.");
}
}
public Properties getDriverProperties() {
return dataSource.getDriverProperties();
}
public void setDefaultTransactionIsolationLevel(Integer defaultTransactionIsolationLevel) {
dataSource.setDefaultTransactionIsolationLevel(defaultTransactionIsolationLevel);
forceCloseAll();
}
public boolean isAutoCommit() {
return dataSource.isAutoCommit();
}
public Integer getDefaultTransactionIsolationLevel() {
return dataSource.getDefaultTransactionIsolationLevel();
}
public String getUsername() {
return dataSource.getUsername();
}
public String getPassword() {
return dataSource.getPassword();
}
private PooledConnection popConnection(String username, String password) throws SQLException {
boolean countedWait = false;
PooledConnection conn = null;
long t = System.currentTimeMillis();
int localBadConnectionCount = 0;
while (conn == null) {
synchronized (state) {
if (state.idleConnections.size() > 0) {
// Pool has available connection
conn = (PooledConnection) state.idleConnections.remove(0);
if (log.isDebugEnabled()) {
log.debug("Checked out connection " + conn.getRealHashCode() + " from pool.");
}
} else {
// Pool does not have available connection
if (state.activeConnections.size() < poolMaximumActiveConnections) {
// Can create new connection
conn = new PooledConnection(dataSource.getConnection(), this);
@SuppressWarnings("unused")
// used in logging, if enabled
Connection realConn = conn.getRealConnection();
if (log.isDebugEnabled()) {
log.debug("Created connection " + conn.getRealHashCode() + ".");
}
} else {
// Cannot create new connection
PooledConnection oldestActiveConnection =
(PooledConnection) state.activeConnections.get(0);
long longestCheckoutTime = oldestActiveConnection.getCheckoutTime();
if (longestCheckoutTime > poolMaximumCheckoutTime) {
// Can claim overdue connection
state.claimedOverdueConnectionCount++;
state.accumulatedCheckoutTimeOfOverdueConnections += longestCheckoutTime;
state.accumulatedCheckoutTime += longestCheckoutTime;
state.activeConnections.remove(oldestActiveConnection);
if (!oldestActiveConnection.getRealConnection().getAutoCommit()) {
oldestActiveConnection.getRealConnection().rollback();
}
conn = new PooledConnection(oldestActiveConnection.getRealConnection(), this);
oldestActiveConnection.invalidate();
if (log.isDebugEnabled()) {
log.debug("Claimed overdue connection " + conn.getRealHashCode() + ".");
}
} else {
// Must wait
try {
if (!countedWait) {
state.hadToWaitCount++;
countedWait = true;
}
if (log.isDebugEnabled()) {
log.debug(
"Waiting as long as " + poolTimeToWait + " milliseconds for connection.");
}
long wt = System.currentTimeMillis();
state.wait(poolTimeToWait);
state.accumulatedWaitTime += System.currentTimeMillis() - wt;
} catch (InterruptedException e) {
break;
}
}
}
}
if (conn != null) {
if (conn.isValid()) {
if (!conn.getRealConnection().getAutoCommit()) {
conn.getRealConnection().rollback();
}
conn.setConnectionTypeCode(
assembleConnectionTypeCode(dataSource.getUrl(), username, password));
conn.setCheckoutTimestamp(System.currentTimeMillis());
conn.setLastUsedTimestamp(System.currentTimeMillis());
state.activeConnections.add(conn);
state.requestCount++;
state.accumulatedRequestTime += System.currentTimeMillis() - t;
} else {
if (log.isDebugEnabled()) {
log.debug(
"A bad connection ("
+ conn.getRealHashCode()
+ ") was returned from the pool, getting another connection.");
}
state.badConnectionCount++;
localBadConnectionCount++;
conn = null;
if (localBadConnectionCount > (poolMaximumIdleConnections + 3)) {
if (log.isDebugEnabled()) {
log.debug("PooledDataSource: Could not get a good connection to the database.");
}
throw new SQLException(
"PooledDataSource: Could not get a good connection to the database.");
}
}
}
}
}
if (conn == null) {
if (log.isDebugEnabled()) {
log.debug(
"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection.");
}
throw new SQLException(
"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection.");
}
return conn;
}
public String getUrl() {
return dataSource.getUrl();
}
private PooledConnection popConnection(String username, String password)
throws SQLException { // 获取一个连接
boolean countedWait = false;
PooledConnection conn = null;
long t = System.currentTimeMillis();
int localBadConnectionCount = 0;
while (conn == null) {
synchronized (state) {
if (!state.idleConnections.isEmpty()) { // pool里还有空闲连接
// Pool has available connection
conn = state.idleConnections.remove(0); // 从空闲list移出一个conn，用做新连接
if (log.isDebugEnabled()) {
log.debug("Checked out connection " + conn.getRealHashCode() + " from pool.");
}
} else { // pool里没有空闲连接了
// Pool does not have available connection
if (state.activeConnections.size() < poolMaximumActiveConnections) { // 活动list没有满
// Can create new connection
conn = new PooledConnection(dataSource.getConnection(), this); // 新建一个PooledConnection
if (log.isDebugEnabled()) {
log.debug("Created connection " + conn.getRealHashCode() + ".");
}
} else { // 活动list已经满了，无法创建新连接
// Cannot create new connection
PooledConnection oldestActiveConnection = state.activeConnections.get(0); // 获取最早开始活动的连接
long longestCheckoutTime =
oldestActiveConnection.getCheckoutTime(); // 获得最老的活动连接的checkout时间
if (longestCheckoutTime > poolMaximumCheckoutTime) { // 如果checkout时间大于最大值
// Can claim overdue connection
state.claimedOverdueConnectionCount++; // 过期连接计数++
state.accumulatedCheckoutTimeOfOverdueConnections +=
longestCheckoutTime; // 累加过期连接的checkout时间
state.accumulatedCheckoutTime += longestCheckoutTime; // 累加checkout时间
state.activeConnections.remove(oldestActiveConnection); // 从活动list移出最老的活动连接，留出空位来啦
if (!oldestActiveConnection.getRealConnection().getAutoCommit()) {
oldestActiveConnection.getRealConnection().rollback(); // 回滚
}
conn =
new PooledConnection(
oldestActiveConnection.getRealConnection(), this); // 新建连接，用最老连接的真连接
oldestActiveConnection.invalidate(); // 最老连接标记无效
if (log.isDebugEnabled()) {
log.debug("Claimed overdue connection " + conn.getRealHashCode() + ".");
}
} else { // 如果checkout时间并没有超过最大值，必须等待
// Must wait
try {
if (!countedWait) { // countedWait原来是false
state.hadToWaitCount++; // 必须等待的计数++
countedWait = true; // countedWait变为true
}
if (log.isDebugEnabled()) {
log.debug(
"Waiting as long as " + poolTimeToWait + " milliseconds for connection.");
}
long wt = System.currentTimeMillis();
state.wait(
poolTimeToWait); // 等poolTimeToWait微秒，pushConnection移出一个连接时会notifyAll来唤醒wait的线程
state.accumulatedWaitTime += System.currentTimeMillis() - wt;
} catch (InterruptedException e) {
break;
}
}
}
}
if (conn != null) { // conn非空，确实建出来了
if (conn.isValid()) { // conn有效
if (!conn.getRealConnection().getAutoCommit()) {
conn.getRealConnection().rollback(); // 这里回滚是干啥？ hama
}
conn.setConnectionTypeCode(
assembleConnectionTypeCode(dataSource.getUrl(), username, password));
conn.setCheckoutTimestamp(System.currentTimeMillis());
conn.setLastUsedTimestamp(System.currentTimeMillis());
state.activeConnections.add(conn); // 加入活动list
state.requestCount++;
state.accumulatedRequestTime += System.currentTimeMillis() - t;
} else { // conn无效
if (log.isDebugEnabled()) {
log.debug(
"A bad connection ("
+ conn.getRealHashCode()
+ ") was returned from the pool, getting another connection.");
}
state.badConnectionCount++;
localBadConnectionCount++;
conn = null;
if (localBadConnectionCount > (poolMaximumIdleConnections + 3)) {
if (log.isDebugEnabled()) {
log.debug("PooledDataSource: Could not get a good connection to the database.");
}
throw new SQLException(
"PooledDataSource: Could not get a good connection to the database.");
}
}
}
}
} // 到这里while结束
if (conn == null) { // 出现了奇葩的Unknown错吧
if (log.isDebugEnabled()) {
log.debug(
"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection.");
}
throw new SQLException(
"PooledDataSource: Unknown severe error condition. The connection pool returned a null connection.");
}
return conn;
}
public Connection getConnection() throws SQLException {
return popConnection(dataSource.getUsername(), dataSource.getPassword()).getProxyConnection();
}
public void setDefaultAutoCommit(boolean defaultAutoCommit) {
dataSource.setAutoCommit(defaultAutoCommit);
forceCloseAll();
}
public void setPassword(String password) {
dataSource.setPassword(password);
forceCloseAll();
}
public void setUsername(String username) {
dataSource.setUsername(username);
forceCloseAll();
}
public void setUrl(String url) {
dataSource.setUrl(url);
forceCloseAll();
}
public void setDriver(String driver) {
dataSource.setDriver(driver);
forceCloseAll();
}
public PooledDataSource(String driver, String url, String username, String password) {
dataSource = new UnpooledDataSource(driver, url, username, password);
expectedConnectionTypeCode =
assembleConnectionTypeCode(
dataSource.getUrl(), dataSource.getUsername(), dataSource.getPassword());
}
public void setDriverProperties(Properties driverProps) {
dataSource.setDriverProperties(driverProps);
forceCloseAll();
}
@Override
public Connection getConnection()
throws SQLException { // 获得连接，即popConnection(...).getProxyConnection()获得代理连接
return popConnection(dataSource.getUsername(), dataSource.getPassword()).getProxyConnection();
}
public String getDriver() {
return dataSource.getDriver();
}