JdbcDataSource.java
/*
** Module : JdbcDataSource.java
** Abstract : JDBC data source which wraps a C3P0 pooled data source
**
** Copyright (c) 2019-2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- --------------------------------Description----------------------------------
** 001 ECF 20190902 Created initial version. Establishes a C3P0 pooled data source per database.
** 002 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 003 RAA 20240423 Modified methods to also include the database configuration.
** RAA 20240426 The DataSource is now also based on the tenant's id, not only the database.
** 004 OM 20240909 Improved Database API.
** 005 OM 20241128 Multi-tenant runtime support: selected the proper persistence context, eventually
** based on [sharedDb] parameter.
** 006 AS 20241209 Implemented a retry system for getting connections.
** 007 LS 20250321 Remove the dataSource from the sources and close it when it becomes broken.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
** You may not represent yourself as Golden Code Development Corporation or FWD.
**
** You may not represent yourself for publicity purposes as associated with
** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
** You may not represent the covered work as solely your work. All modified
** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.persist.orm;
import java.sql.*;
import java.util.*;
import java.util.concurrent.*;
import javax.sql.DataSource;
import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.util.logging.*;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import com.mchange.v2.resourcepool.ResourcePoolException;
/**
* A JDBC data source which wraps a C3P0 pooled data source. Access to pooled data sources is via
* static methods, and is organized by database.
*/
class JdbcDataSource
{
/** Logger */
static final CentralLogger log = CentralLogger.get(JdbcDataSource.class.getName());
/** Concurrent map of instances, keyed by database keys. */
private static Map<DatabaseKey, JdbcDataSource> sources = new ConcurrentHashMap<>();
/** Delegate data source */
private final DataSource dataSource;
/** Flag indicating whether data source supports batch operations */
private final boolean batch;
/**
* Get a JDBC connection from the pool, creating it if necessary.
*
* @param database
* Database with which the connection must be established.
* @param cfg
* The configuration of the given database.
* @param tenantName
* The name of the tenant.
*
* @return JDBC connection.
*
* @throws PersistenceException
* if there is an error configuring or obtaining the data source or connection.
*/
static Connection getConnection(Database database, DatabaseConfig cfg, String tenantName)
throws PersistenceException
{
Connection connection = null;
Exception e = null;
int retryConnectionCount = 0;
boolean retry = true;
while (retry)
{
retry = false;
try
{
DataSource ds = getDataSource(database, cfg, tenantName).dataSource;
// There is a possibility that another thread will throw an
// InterruptedException at the same time a checkout of a
// connection is attempted by this thread and it will fail, in this cases,
// the checkout is retried.
// It is highly unlikely that all 3 attempts will be interrupted by another thread,
// but if that happens, we will need to adjust the retryConnectionCount.
while (connection == null && retryConnectionCount < 3)
{
try
{
connection = ds.getConnection();
}
catch (SQLException exc)
{
e = exc;
Throwable cause = exc.getCause();
// check if the underlying cause of the exception is a broken resource pool
// the c3p0 pool can declare itself "broken" if it fails to obtain a connection and
// has the breakAfterAcquireFailure flag enabled.
if (cause instanceof ResourcePoolException &&
cause.getMessage().equals(DBUtils.BROKEN_POOL_ERROR))
{
DatabaseKey key = new DatabaseKey(database, tenantName);
if (ds instanceof ComboPooledDataSource)
{
// the broken datasource must be closed manually to release its resources.
((ComboPooledDataSource) ds).close();
}
// the dataSource is broken, we need to remove it
sources.remove(key);
// we detected now that the datasource is broken,
// but maybe the connection was restored in the meantime
// try getting a new one before throwing the PersistenceException
retry = true;
break;
}
retryConnectionCount++;
}
}
}
catch (PersistenceException exc)
{
e = exc;
}
}
if (connection == null)
{
throw new PersistenceException(DBUtils.JDBC_CONNECTION_ERROR, e);
}
return connection;
}
/**
* Indicate whether the data source represented by the given database object supports batch
* operations.
*
* @param database
* Database for which batch support information is needed.
*
* @return {@code true} if batch operations are supported, else {@code false}.
*
* @throws PersistenceException
* if database metadata needs to be queried and there is an error doing so.
*/
static boolean supportsBatch(Database database)
throws PersistenceException
{
return getDataSource(database, null, null).batch;
}
/**
* Get the JDBC data source for the given database.
*
* @param database
* Database object which identifies the data source.
* @param cfg
* The configuration of the given database.
* @param tenantName
* The name of the tenant.
*
* @return Data source object.
*
* @throws PersistenceException
* if there is an error configuring or obtaining the data source.
*/
private static JdbcDataSource getDataSource(Database database, DatabaseConfig cfg, String tenantName)
throws PersistenceException
{
DatabaseKey dbKey = new DatabaseKey(database, tenantName);
JdbcDataSource jds = sources.get(dbKey);
if (jds == null)
{
DataSource dataSource = database.isTemporary()
? new TempTableDataSourceProvider().getDataSource(database, cfg)
: PooledDataSourceProvider.getInstance().getDataSource(database, cfg, tenantName);
jds = new JdbcDataSource(dataSource);
sources.put(dbKey, jds);
}
return jds;
}
/**
* Private constructor; all access is via static methods. Reads configuration data from the
* application directory and constructs the data source accordingly.
*
* @param dataSource
* The data source. Note that only the database name is used directly to configure the data
* source; all other information is read from the directory or is derived, based on the database
* type.
*
* @throws PersistenceException
* if there is an error configuring or obtaining the data source.
*/
private JdbcDataSource(DataSource dataSource)
throws PersistenceException
{
this.dataSource = dataSource;
try (Connection conn = dataSource.getConnection())
{
DatabaseMetaData dbMeta = conn.getMetaData();
this.batch = dbMeta.supportsBatchUpdates();
}
catch (SQLException exc)
{
// if an error is encountered when using a c3p0 datasource
// it needs to be closed manually to release its resources
if (dataSource instanceof ComboPooledDataSource)
{
((ComboPooledDataSource) dataSource).close();
}
throw new PersistenceException("Error querying database metadata", exc);
}
}
/**
* Class that handles a database key for the {@code sources} map.
* This involves one component (the database instance) if we are not in multi-tenancy mode,
* or two components (the database instance and the tenant id) otherwise.
*/
private static class DatabaseKey
{
/** The database instance to work with. */
private final Database db;
/** The tenant id. This will be {@code null} if multi-tenancy is not enabled. */
private final String tenantName;
/** The hash code for the key. */
private final int hashCode;
/**
* Basic constructor.
*
* @param db
* The database instance to work with.
* @param tenantName
* The name of the tenant.
*/
private DatabaseKey(Database db, String tenantName)
{
this.db = db;
this.tenantName = tenantName;
hashCode = tenantName != null ?
(37 * 17 + db.hashCode()) * 37 + tenantName.hashCode() :
37 * 17 + db.hashCode();
}
/**
* Calculate a hash code for this object.
*
* @return Hash code.
*/
@Override
public int hashCode()
{
return hashCode;
}
/**
* Test the equality between this instance and another given one.
*
* @return {@code true} if the objects match, {@code false} otherwise.
*/
@Override
public boolean equals(Object o)
{
if (this == o)
{
// Same instance.
return true;
}
if (!(o instanceof DatabaseKey))
{
// Impossible to be equivalent.
return false;
}
DatabaseKey that = (DatabaseKey) o;
if (!this.db.equals(that.db))
{
return false;
}
if (this.tenantName != null && that.tenantName == null ||
this.tenantName == null && that.tenantName != null)
{
return false;
}
if (this.tenantName == null && that.tenantName == null)
{
return true;
}
return this.tenantName.equals(that.tenantName);
}
}
}