http://hsqldb.org: HSQLDB - Lightweight 100% Java SQL Database Engine (The HSQL Development Group)
  • Blaine Simpson 
/* Copyright (c) 2001-2019, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
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 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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package org.hsqldb.jdbc;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.Wrapper;
import java.util.Properties;
import java.util.concurrent.atomic.AtomicIntegerArray;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.naming.Referenceable;
import javax.naming.StringRefAddr;
import javax.sql.ConnectionEvent;
import javax.sql.ConnectionEventListener;
import javax.sql.DataSource;
import javax.sql.PooledConnection;
import javax.sql.StatementEvent;
import javax.sql.StatementEventListener;

import org.hsqldb.jdbc.pool.JDBCPooledConnection;
import org.hsqldb.jdbc.pool.JDBCPooledDataSource;






HSQLDB-Specific Information:
 
 A connection pool for HyperSQL connections. This implementation of DataSource is dedicated to HyperSQL and guarantees all connection states are automatically reset when a connection is reused.
 The methods of the parent class, JDBCCommonDataSource are used to specify the database URL, user, password, and / or connection properties.





Author:Fred Toussi (fredt@users dot sourceforge.net)
Version:2.3.4
Since:2.2.9
/**
 * <!-- start Release-specific documentation -->
 * <div class="ReleaseSpecificDocumentation">
 * <h3>HSQLDB-Specific Information:</h3> <p>
 *
 * A connection pool for HyperSQL connections. This implementation of
 * {@link javax.sql.DataSource DataSource} is dedicated to HyperSQL and
 * guarantees all connection states are automatically reset when a connection
 * is reused.<p>
 *
 * The methods of the parent class,
 * {@link JDBCCommonDataSource} are used to specify the database URL, user,
 * password, and / or connection properties.<p>
 *
 * </div>
 * <!-- end Release-specific documentation -->
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.4
 * @since 2.2.9
 */
@SuppressWarnings("serial")
public class JDBCPool implements DataSource,
                   Referenceable, ConnectionEventListener,
                   StatementEventListener, Wrapper {

    
Retrieves a new connection using the properties that have already been
set.

Throws:
Returns: a connection to the data source
/**
     * Retrieves a new connection using the properties that have already been
     * set.
     *
     * @return  a connection to the data source
     * @exception SQLException if a database access error occurs
     */
    public Connection getConnection() throws SQLException {

        int retries = 300;

        if (source.loginTimeout != 0){
            retries = source.loginTimeout * 10;
        }

        if (closed) {
            throw new SQLException("connection pool is closed");
        }

        for (int count = 0; count < retries; count++) {
            for (int i = 0; i < states.length(); i++) {
                if (states.compareAndSet(i, RefState.available,
                                        RefState.allocated)) {
                    return connections[i].getConnection();
                }

                if (states.compareAndSet(i, RefState.empty,
                                        RefState.allocated)) {
                    try {
                        JDBCPooledConnection connection =
                            (JDBCPooledConnection) source.getPooledConnection();

                        connection.addConnectionEventListener(this);
                        connection.addStatementEventListener(this);
                        connections[i] = connection;

                        return connections[i].getConnection();
                    } catch (SQLException e) {
                        states.set(i, RefState.empty);
                    }
                }
            }

            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {}
        }

        throw JDBCUtil.invalidArgument();
    }

    
Retrieves a new connection using the given username and password,
and the database url that has been set. No other properties are
used for the connection.
This method can be used only with the same username and password used
for the connection pool. The first call to this method sets the user name
and password for the connection pool.

Params:
  • username – the database user on whose behalf the connection is
 being made
  • password – the user's password
Throws:
Returns: a connection to the data source
/**
     * Retrieves a new connection using the given username and password,
     * and the database url that has been set. No other properties are
     * used for the connection.
     *
     * This method can be used only with the same username and password used
     * for the connection pool. The first call to this method sets the user name
     * and password for the connection pool.
     *
     * @param username the database user on whose behalf the connection is
     *  being made
     * @param password the user's password
     * @return  a connection to the data source
     * @exception SQLException if a database access error occurs
     */
    public Connection getConnection(String username, String password)
            throws SQLException {

        String user = getUser();

        if (username == null || password == null) {
            throw JDBCUtil.nullArgument();
        }

        if ( user == null) {
            setUser(username);
            setPassword(password);
        } else if (!user.equals(username)) {
            throw JDBCUtil.invalidArgument("user name does not match");
        }

        return getConnection();
    }

    // ------------------------- JDBC 4.0 -----------------------------------
    // ------------------- java.sql.Wrapper implementation ---------------------

    
Returns an object that implements the given interface to allow access to
non-standard methods, or standard methods not exposed by the proxy.
If the receiver implements the interface then the result is the receiver
or a proxy for the receiver. If the receiver is a wrapper
and the wrapped object implements the interface then the result is the
wrapped object or a proxy for the wrapped object. Otherwise return the
the result of calling unwrap recursively on the wrapped object
or a proxy for that result. If the receiver is not a
wrapper and does not implement the interface, then an SQLException is thrown.

Params:
  • iface – A Class defining an interface that the result must implement.
Throws:
  • SQLException – If no object found that implements the interface
Returns:an object that implements the interface. May be a proxy for the actual implementing object.
Since:JDK 1.6, HSQLDB 2.0
/**
     * Returns an object that implements the given interface to allow access to
     * non-standard methods, or standard methods not exposed by the proxy.
     *
     * If the receiver implements the interface then the result is the receiver
     * or a proxy for the receiver. If the receiver is a wrapper
     * and the wrapped object implements the interface then the result is the
     * wrapped object or a proxy for the wrapped object. Otherwise return the
     * the result of calling <code>unwrap</code> recursively on the wrapped object
     * or a proxy for that result. If the receiver is not a
     * wrapper and does not implement the interface, then an <code>SQLException</code> is thrown.
     *
     * @param iface A Class defining an interface that the result must implement.
     * @return an object that implements the interface. May be a proxy for the actual implementing object.
     * @throws java.sql.SQLException If no object found that implements the interface
     * @since JDK 1.6, HSQLDB 2.0
     */
    @SuppressWarnings("unchecked")
    public <T>T unwrap(java.lang.Class<T> iface) throws java.sql.SQLException {
        if (isWrapperFor(iface)) {
            return (T) this;
        }

        throw JDBCUtil.invalidArgument("iface: " + iface);
    }

    
Returns true if this either implements the interface argument or is directly or indirectly a wrapper
for an object that does. Returns false otherwise. If this implements the interface then return true,
else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped
object. If this does not implement the interface and is not a wrapper, return false.
This method should be implemented as a low-cost operation compared to unwrap so that
callers can use this method to avoid expensive unwrap calls that may fail. If this method
returns true then calling unwrap with the same argument should succeed.

Params:
  • iface – a Class defining an interface.
Throws:
  • SQLException –  if an error occurs while determining whether this is a wrapper
for an object with the given interface.
Returns:true if this implements the interface or directly or indirectly wraps an object that does.
Since:JDK 1.6, HSQLDB 2.0
/**
     * Returns true if this either implements the interface argument or is directly or indirectly a wrapper
     * for an object that does. Returns false otherwise. If this implements the interface then return true,
     * else if this is a wrapper then return the result of recursively calling <code>isWrapperFor</code> on the wrapped
     * object. If this does not implement the interface and is not a wrapper, return false.
     * This method should be implemented as a low-cost operation compared to <code>unwrap</code> so that
     * callers can use this method to avoid expensive <code>unwrap</code> calls that may fail. If this method
     * returns true then calling <code>unwrap</code> with the same argument should succeed.
     *
     * @param iface a Class defining an interface.
     * @return true if this implements the interface or directly or indirectly wraps an object that does.
     * @throws java.sql.SQLException  if an error occurs while determining whether this is a wrapper
     * for an object with the given interface.
     * @since JDK 1.6, HSQLDB 2.0
     */
    public boolean isWrapperFor(java.lang.Class<?> iface)
            throws java.sql.SQLException {
        return ((iface != null) && iface.isAssignableFrom(this.getClass()));
    }

    
Retrieves the Reference of this object.

Throws:
  • NamingException – If a naming exception was encountered
         while retrieving the reference.
Returns:The non-null Reference of this object.
/**
     * Retrieves the Reference of this object.
     *
     * @return The non-null Reference of this object.
     * @exception NamingException If a naming exception was encountered
     *          while retrieving the reference.
     */
    public Reference getReference() throws NamingException {
        String    cname = "org.hsqldb.jdbc.JDBCDataSourceFactory";
        Reference ref   = new Reference(getClass().getName(), cname, null);

        ref.add(new StringRefAddr("database", source.getDatabase()));
        ref.add(new StringRefAddr("user", source.getUser()));
        ref.add(new StringRefAddr("password", source.password));
        ref.add(new StringRefAddr("loginTimeout",
                                  Integer.toString(source.loginTimeout)));
        ref.add(new StringRefAddr("poolSize", Integer.toString(connections.length)));

        return ref;
    }

    // ------------------------ event listener ------------------------
    public void connectionClosed(ConnectionEvent event) {
        PooledConnection connection = (PooledConnection) event.getSource();

        for (int i = 0; i < connections.length; i++) {
            if (connections[i] == connection) {
                states.set(i, RefState.available);

                break;
            }
        }
    }

    public void connectionErrorOccurred(ConnectionEvent event) {
        PooledConnection connection = (PooledConnection) event.getSource();

        for (int i = 0; i < connections.length; i++) {
            if (connections[i] == connection) {
                states.set(i, RefState.allocated);
                connections[i] = null;
                states.set(i, RefState.empty);
                break;
            }
        }
    }

    public void statementClosed(StatementEvent event) {}

    public void statementErrorOccurred(StatementEvent event) {}


    // ------------------------ event listener ------------------------
    
Retrieves the log writer for this DataSource
object.

The log writer is a character output stream to which all logging
and tracing messages for this data source will be
printed.  This includes messages printed by the methods of this
object, messages printed by methods of other objects manufactured
by this object, and so on.  Messages printed to a data source
specific log writer are not printed to the log writer associated
with the java.sql.DriverManager class.  When a
DataSource object is
created, the log writer is initially null; in other words, the
default is for logging to be disabled.

Throws:
See Also:
Returns:the log writer for this data source or null if
       logging is disabled
Since:1.4
/**
     * <p>Retrieves the log writer for this <code>DataSource</code>
     * object.
     *
     * <p>The log writer is a character output stream to which all logging
     * and tracing messages for this data source will be
     * printed.  This includes messages printed by the methods of this
     * object, messages printed by methods of other objects manufactured
     * by this object, and so on.  Messages printed to a data source
     * specific log writer are not printed to the log writer associated
     * with the <code>java.sql.DriverManager</code> class.  When a
     * <code>DataSource</code> object is
     * created, the log writer is initially null; in other words, the
     * default is for logging to be disabled.
     *
     * @return the log writer for this data source or null if
     *        logging is disabled
     * @exception java.sql.SQLException if a database access error occurs
     * @see #setLogWriter
     * @since 1.4
     */
    public PrintWriter getLogWriter() throws SQLException {
        return source.getLogWriter();
    }

    
Sets the log writer for this DataSource
object to the given java.io.PrintWriter object.

The log writer is a character output stream to which all logging
and tracing messages for this data source will be
printed.  This includes messages printed by the methods of this
object, messages printed by methods of other objects manufactured
by this object, and so on.  Messages printed to a data source-
specific log writer are not printed to the log writer associated
with the java.sql.DriverManager class. When a
DataSource object is created the log writer is
initially null; in other words, the default is for logging to be
disabled.

Params:
  • out – the new log writer; to disable logging, set to null
Throws:
See Also:
Since:1.4
/**
     * <p>Sets the log writer for this <code>DataSource</code>
     * object to the given <code>java.io.PrintWriter</code> object.
     *
     * <p>The log writer is a character output stream to which all logging
     * and tracing messages for this data source will be
     * printed.  This includes messages printed by the methods of this
     * object, messages printed by methods of other objects manufactured
     * by this object, and so on.  Messages printed to a data source-
     * specific log writer are not printed to the log writer associated
     * with the <code>java.sql.DriverManager</code> class. When a
     * <code>DataSource</code> object is created the log writer is
     * initially null; in other words, the default is for logging to be
     * disabled.
     *
     * @param out the new log writer; to disable logging, set to null
     * @exception SQLException if a database access error occurs
     * @see #getLogWriter
     * @since 1.4
     */
    public void setLogWriter(java.io.PrintWriter out) throws SQLException {
        source.setLogWriter(out);
    }

    
Sets the maximum time in seconds that this data source will wait
while attempting to connect to a database.  A value of zero
specifies that the timeout is the default system timeout
if there is one; otherwise, it specifies that there is no timeout.
When a DataSource object is created, the login timeout is
initially zero.

Params:
  • seconds – the data source login time limit
Throws:
See Also:
Since:1.4
/**
     * <p>Sets the maximum time in seconds that this data source will wait
     * while attempting to connect to a database.  A value of zero
     * specifies that the timeout is the default system timeout
     * if there is one; otherwise, it specifies that there is no timeout.
     * When a <code>DataSource</code> object is created, the login timeout is
     * initially zero.
     *
     * @param seconds the data source login time limit
     * @exception SQLException if a database access error occurs.
     * @see #getLoginTimeout
     * @since 1.4
     */
    public void setLoginTimeout(int seconds) throws SQLException {
        source.setLoginTimeout(seconds);
    }

    
Gets the maximum time in seconds that this data source can wait
while attempting to connect to a database.  A value of zero
means that the timeout is the default system timeout
if there is one; otherwise, it means that there is no timeout.
When a DataSource object is created, the login timeout is
initially zero.

Throws:
See Also:
Returns:the data source login time limit
Since:1.4
/**
     * Gets the maximum time in seconds that this data source can wait
     * while attempting to connect to a database.  A value of zero
     * means that the timeout is the default system timeout
     * if there is one; otherwise, it means that there is no timeout.
     * When a <code>DataSource</code> object is created, the login timeout is
     * initially zero.
     *
     * @return the data source login time limit
     * @exception SQLException if a database access error occurs.
     * @see #setLoginTimeout
     * @since 1.4
     */
    public int getLoginTimeout() throws SQLException {
        return source.getLoginTimeout();
    }

    // ------------------------ custom public methods ------------------------

    
Retrieves the description of the data source. 


Returns:the description
/**
     * Retrieves the description of the data source. <p>
     *
     * @return the description
     */
    public String getDescription() {
        return "org.hsqldb.jdbc.JDBCPool max size " + connections.length;
    }

    
Retrieves the name of the data source. 


Returns:the description
/**
     * Retrieves the name of the data source. <p>
     *
     * @return the description
     */
    public String getDataSourceName() {
        return "org.hsqldb.jdbc.JDBCPool";
    }

    
Synonym for getUrl().

Returns:the jdbc database connection url attribute
/**
     * Synonym for getUrl().
     *
     * @return the jdbc database connection url attribute
     */
    public String getDatabaseName() {
        return source.getUrl();
    }

    
Synonym for getUrl().

Returns:the jdbc database connection url attribute
/**
     * Synonym for getUrl().
     *
     * @return the jdbc database connection url attribute
     */
    public String getDatabase() {
        return source.getDatabase();
    }

    
Retrieves the jdbc database connection url attribute. 


Returns:the jdbc database connection url attribute
/**
     * Retrieves the jdbc database connection url attribute. <p>
     *
     * @return the jdbc database connection url attribute
     */
    public String getUrl() {
        return source.getUrl();
    }

    
Retrieves the jdbc database connection url attribute. 


Returns:the jdbc database connection url attribute
/**
     * Retrieves the jdbc database connection url attribute. <p>
     *
     * @return the jdbc database connection url attribute
     */
    public String getURL() {
        return source.getUrl();
    }

    
Retrieves the user name for the connection. 


Returns:the username for the connection
/**
     * Retrieves the user name for the connection. <p>
     *
     * @return the username for the connection
     */
    public String getUser() {
        return source.getUser();
    }

    
Synonym for setUrl(String). 


Params:
  • databaseName – the new value for the attribute
/**
     * Synonym for setUrl(String). <p>
     *
     * @param databaseName the new value for the attribute
     */
    public void setDatabaseName(String databaseName) {
        source.setDatabaseName(databaseName);
    }

    
Synonym for setUrl(String). 


Params:
  • database – the new value for the attribute
/**
     * Synonym for setUrl(String). <p>
     *
     * @param database the new value for the attribute
     */
    public void setDatabase(String database) {
        source.setDatabase(database);
    }

    
Sets the jdbc database URL. 


Params:
  • url – the new value of this object's jdbc database connection
     url attribute
/**
     * Sets the jdbc database URL. <p>
     *
     * @param url the new value of this object's jdbc database connection
     *      url attribute
     */
    public void setUrl(String url) {
        source.setUrl(url);
    }

    
Sets the jdbc database URL. 


Params:
  • url – the new value of this object's jdbc database connection
     url attribute
/**
     * Sets the jdbc database URL. <p>
     *
     * @param url the new value of this object's jdbc database connection
     *      url attribute
     */
    public void setURL(String url) {
        source.setUrl(url);
    }

    
Sets the password for the user name.

Params:
  • password – the password
/**
     * Sets the password for the user name.
     *
     * @param password the password
     */
    public void setPassword(String password) {
        source.setPassword(password);
    }

    
Sets the user name.

Params:
  • user – the user id
/**
     * Sets the user name.
     *
     * @param user the user id
     */
    public void setUser(String user) {
        source.setUser(user);
    }

    
Sets connection properties. If user / password / loginTimeout has been
set with one of the setXXX() methods it will be added to the Properties
object.

Params:
  • props – properties.  If null, then existing properties will be
                          cleared/replaced.
/**
     * Sets connection properties. If user / password / loginTimeout has been
     * set with one of the setXXX() methods it will be added to the Properties
     * object.
     *
     * @param props properties.  If null, then existing properties will be
     *                           cleared/replaced.
     */
    public void setProperties(Properties props) {
        source.setProperties(props);
    }

    //------------------------- JDBC 4.1 -----------------------------------

    
Return the parent Logger of all the Loggers used by this data source. This
should be the Logger farthest from the root Logger that is
still an ancestor of all of the Loggers used by this data source. Configuring
this Logger will affect all of the log messages generated by the data source.
In the worst case, this may be the root Logger.

Throws:
Returns:the parent Logger for this data source
Since:JDK 1.7 M11 2010/09/10 (b123), HSQLDB 2.2.9
/**
     * Return the parent Logger of all the Loggers used by this data source. This
     * should be the Logger farthest from the root Logger that is
     * still an ancestor of all of the Loggers used by this data source. Configuring
     * this Logger will affect all of the log messages generated by the data source.
     * In the worst case, this may be the root Logger.
     *
     * @return the parent Logger for this data source
     * @throws SQLFeatureNotSupportedException if the data source does not use <code>java.util.logging</code>.
     * @since JDK 1.7 M11 2010/09/10 (b123), HSQLDB 2.2.9
     */
    public java.util.logging.Logger getParentLogger()
    throws java.sql.SQLFeatureNotSupportedException {
        throw (java.sql.SQLFeatureNotSupportedException) JDBCUtil.notSupported();
    }

    // ------------------------ custom public methods ------------------------

    
Creates a connection pool with the maximum size of 8. The database and connection settings are made before the getConnection() is called. 
/**
     * Creates a connection pool with the maximum size of 8. The database and
     * connection settings are made before the {@link #getConnection()} is called.
     */
    public JDBCPool() {
        this(10);
    }

    
Creates a connection pool with the given maximum size. The database and connection settings are made before the getConnection() is called. 
Params:
  • size – int maximum size of the pool
/**
     * Creates a connection pool with the given maximum size. The database and
     * connection settings are made before the {@link #getConnection()} is called.
     *
     * @param size int maximum size of the pool
     */
    public JDBCPool(int size) {
        source = new JDBCPooledDataSource();
        connections = new JDBCPooledConnection[size];
        states = new AtomicIntegerArray(size);    }

    
Closes the pool immediately. Waits the given number of seconds before
closing all existing connections in the pool.

Params:
  • wait – int number of seconds to wait before closing the connections, maximum 60 seconds
Throws:
/**
     * Closes the pool immediately. Waits the given number of seconds before
     * closing all existing connections in the pool.
     *
     * @param wait int number of seconds to wait before closing the connections, maximum 60 seconds
     * @throws SQLException on any error
     */
    public void close(int wait) throws SQLException {

        if (wait <0 || wait > 60) {
            throw JDBCUtil.outOfRangeArgument();
        }
        if (closed) {
            return;
        }

        closed = true;

        try {
            Thread.sleep(1000 * wait);
        } catch (Throwable t) {}

        for (int i = 0; i < connections.length; i++) {
            if (connections[i] != null) {
                connections[i].release();
            }
        }

        for (int i = 0; i < connections.length; i++) {
            connections[i] = null;
        }

    }
    // ------------------------ internal ------------------------
    interface RefState {
        int empty     = 0;
        int available = 1;
        int allocated = 2;
    }


    AtomicIntegerArray       states;
    JDBCPooledConnection[]   connections;
    JDBCPooledDataSource     source;
    volatile boolean         closed;
}