c3p0

https://github.com/swaldman/c3p0
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c3p0 is a mature, highly concurrent JDBC Connection pooling library with support for caching and...
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### Define extensions in configuration files

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Examples of setting the extensions map using different configuration file formats.

```properties
c3p0.extensions.initSql=SET SCHEMA 'foo' c3p0.extensions.timezone=PDT
```

```hocon
c3p0 { extensions { initSql=SET SCHEMA 'foo' timezone=PDT } }
```

```xml
<c3p0-config> <default-config> <extensions> <property name="initSql">SET SCHEMA 'foo'</property> <property name="timezone">PDT</property> </extensions> </default-config> </c3p0-config>
```

--------------------------------

### Mix named, per-user, and extension configurations

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Examples showing how to combine standard, named, and user-defined configurations in various file formats.

```properties
c3p0.maxPoolSize=30 c3p0.extensions.initSql=SET SCHEMA 'default' c3p0.named-configs.intergalactoApp.maxPoolSize=1000 c3p0.named-configs.intergalactoApp.extensions.initSql=SET SCHEMA 'intergalacto' c3p0.named-configs.user-overrides.steve.maxPoolSize=20
```

```hocon
c3p0 { maxPoolSize=30 extensions { initSql=SET SCHEMA 'default' } named-configs { intergalactoApp { maxPoolSize=1000 user-overrides { steve { maxPoolSize=20 } } extensions { initSql=SET SCHEMA 'intergalacto' } } } }
```

```xml
<c3p0-config> <default-config> <property name="maxPoolSize">30</property> <extensions> <property name="initSql">SET SCHEMA 'default'</property> </extensions> </default-config> <named-config name="intergalactoApp"> <property name="maxPoolSize">1000</property> <user-overrides name="steve"> <property name="maxPoolSize">20</property> </user-overrides> <extensions> <property name="initSql">SET SCHEMA 'intergalacto'</property> </extensions> </named-config> </c3p0-config>
```

--------------------------------

### Define c3p0 configuration in XML

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Example of a c3p0-config.xml file defining default settings, named configurations, and user-specific overrides.

```xml
<c3p0-config> <default-config> <property name="automaticTestTable">con\_test</property> <property name="checkoutTimeout">30000</property> <property name="idleConnectionTestPeriod">30</property> <property name="initialPoolSize">10</property> <property name="maxIdleTime">30</property> <property name="maxPoolSize">100</property> <property name="minPoolSize">10</property> <property name="maxStatements">200</property> <user-overrides user="test-user"> <property name="maxPoolSize">10</property> <property name="minPoolSize">1</property> <property name="maxStatements">0</property> </user-overrides> </default-config> <!-- This app is massive! --> <named-config name="intergalactoApp"> <property name="acquireIncrement">50</property> <property name="initialPoolSize">100</property> <property name="minPoolSize">50</property> <property name="maxPoolSize">1000</property> <!-- intergalactoApp adopts a different approach to configuring statement caching --> <property name="maxStatements">0</property> <property name="maxStatementsPerConnection">5</property> <!-- he's important, but there's only one of him --> <user-overrides user="master-of-the-universe"> <property name="acquireIncrement">1</property> <property name="initialPoolSize">1</property> <property name="minPoolSize">1</property> <property name="maxPoolSize">5</property> <property name="maxStatementsPerConnection">50</property> </user-overrides> </named-config> </c3p0-config>
```

--------------------------------

### PooledDataSource status method signatures

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Examples of the overloaded method signatures available for querying connection counts.

```java
public int getNumConnectionsDefaultUser()
public int getNumConnections(String username, String password)
public int getNumConnectionsAllUsers()
```

--------------------------------

### Configure Hibernate-specific c3p0 properties

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Example of setting c3p0 properties within a Hibernate configuration file to debug connection leaks.

```properties
hibernate.c3p0.unreturnedConnectionTimeout=30 hibernate.c3p0.debugUnreturnedConnectionStackTraces=true
```

--------------------------------

### Implementing a FixedThreadPoolExecutorTaskRunnerFactory

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Example implementation of AbstractExecutorTaskRunnerFactory that manages its own fixed thread pool.

```java
public final class FixedThreadPoolExecutorTaskRunnerFactory extends AbstractExecutorTaskRunnerFactory { // for lazy initialization, called only on first-use protected Executor findCreateExecutor( TaskRunnerInit init ) { ThreadFactory tf = new TaskRunnerThreadFactory( init.contextClassLoaderSourceIfSupported, init.privilege_spawned_threads_if_supported, init.threadLabelIfSupported, null ); return Executors.newFixedThreadPool( init.num_threads_if_supported, tf ); } protected boolean taskRunnerOwnsExecutor() { return true; } protected ThreadPoolReportingAsynchronousRunner createTaskRunner( TaskRunnerInit init, Timer timer ) { return new FixedThreadPoolExecutorAsynchronousRunner( init, timer ); } protected final class FixedThreadPoolExecutorAsynchronousRunner extends AbstractExecutorAsynchronousRunner { protected FixedThreadPoolExecutorAsynchronousRunner( TaskRunnerInit init, Timer timer ) { super( init, timer ); } public int getThreadCount() { return init.num_threads_if_supported; } public int getIdleCount() { return getThreadCount() - getActiveCount(); } } }
```

--------------------------------

### Instantiate with Named Configuration

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Shows how to initialize a DataSource using a specific named configuration defined in the application settings.

```java
ComboPooledDataSource cpds = new ComboPooledDataSource("intergalactoApp");
```

--------------------------------

### Implement a ConnectionCustomizer with extensions

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

A Java implementation of a ConnectionCustomizer that retrieves and executes an initSql extension upon connection checkout.

```java
package mypkg; import java.sql.*; import com.mchange.v2.c3p0.AbstractConnectionCustomizer; public class InitSqlConnectionCustomizer extends AbstractConnectionCustomizer { private String getInitSql( String parentDataSourceIdentityToken ) { return (String) extensionsForToken( parentDataSourceIdentityToken ).get ( "initSql" ); } public void onCheckOut( Connection c, String parentDataSourceIdentityToken ) throws Exception { String initSql = getInitSql( parentDataSourceIdentityToken ); if ( initSql != null ) { Statement stmt = null; try { stmt = c.createStatement(); stmt.executeUpdate( initSql ); } finally { if ( stmt != null ) stmt.close(); } } } }
```

--------------------------------

### Define c3p0 configuration via System properties

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Pass configuration settings directly to the JVM using the -D flag. System properties take precedence over settings in c3p0.properties.

```bash
java -Dc3p0.maxStatements=150 -Dc3p0.maxIdleTime=1800 example.MyC3P0App
```

--------------------------------

### Define Named Configurations in Properties File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define default and named configuration parameters using the properties file format.

```properties
# define default-config param values c3p0.maxPoolSize=30 c3p0.minPoolSize=10 # define params for a named config called intergalactoApp c3p0.named-configs.intergalactoApp.maxPoolSize=1000 c3p0.named-configs.intergalactoApp.minPoolSize=100 c3p0.named-configs.intergalactoApp.numHelperThreads=50 # define params for a named config called littleTeenyApp c3p0.named-configs.littleTeenyApp.maxPoolSize=5 c3p0.named-configs.littleTeenyApp.minPoolSize=2
```

--------------------------------

### Define Named Configurations in XML File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define default and named configuration parameters using the XML format.

```xml
<c3p0-config> <default-config> <property name="maxPoolSize">30</property> <property name="minPoolSize">10</property> </default-config> <named-config name="intergalactoApp"> <property name="maxPoolSize">1000</property> <property name="minPoolSize">100</property> <property name="numHelperThreads">50</property> </named-config> <named-config name="littleTeenyApp"> <property name="maxPoolSize">5</property> <property name="minPoolSize">2</property> </named-config> </c3p0-config>
```

--------------------------------

### Define Per-User Configurations in XML File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define configuration overrides for specific users using the XML format.

```xml
<c3p0-config> <default-config> <property name="maxPoolSize">30</property> <property name="minPoolSize">10</property> <user-overrides user="steve"> <property name="maxPoolSize">15</property> <property name="minPoolSize">5</property> </user-overrides> <user-overrides user="ramona"> <property name="maxPoolSize">50</property> <property name="minPoolSize">20</property> </user-overrides> </default-config> </c3p0-config>
```

--------------------------------

### Implement a ConnectionCustomizer

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Create a custom class to hook into connection lifecycle events. Implementations should be immutable and have a public no-argument constructor.

```java
import com.mchange.v2.c3p0.*; import java.sql.Connection; public class VerboseConnectionCustomizer { public void onAcquire( Connection c, String pdsIdt ) { System.err.println("Acquired " + c + " [" + pdsIdt + "]"); // override the default transaction isolation of // newly acquired Connections c.setTransactionIsolation( Connection.REPEATABLE_READ ); } public void onDestroy( Connection c, String pdsIdt ) { System.err.println("Destroying " + c + " [" + pdsIdt + "]"); } public void onCheckOut( Connection c, String pdsIdt ) { System.err.println("Checked out " + c + " [" + pdsIdt + "]"); } public void onCheckIn( Connection c, String pdsIdt ) { System.err.println("Checking in " + c + " [" + pdsIdt + "]"); } }
```

--------------------------------

### Initialize and Configure ComboPooledDataSource

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Create a new connection pool by setting the JDBC driver class, URL, and credentials.

```java
import com.mchange.v2.c3p0.*; ... ComboPooledDataSource cpds = new ComboPooledDataSource(); cpds.setDriverClass( "org.postgresql.Driver" ); //loads the jdbc driver cpds.setJdbcUrl( "jdbc:postgresql://localhost/testdb" ); cpds.setUser("dbuser"); cpds.setPassword("dbpassword");
```

--------------------------------

### Define c3p0 properties in a properties file

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Use a standard Java properties file format to set configuration keys. Place the file at the root of the classpath as c3p0.properties.

```properties
# turn on statement pooling c3p0.maxStatements=150 # close pooled Connections that go unused for # more than half an hour c3p0.maxIdleTime=1800
```

--------------------------------

### Create Pooled DataSources with Named Configurations

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Uses a named configuration alongside property overrides to initialize a pooled DataSource.

```java
// create the PooledDataSource using the a named configuration and specified overrides // "intergalactoApp" is a named configuration ds_pooled = DataSources.pooledDataSource( ds_unpooled, "intergalactoApp", overrides );
```

--------------------------------

### Define Per-User Configurations in Properties File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define configuration overrides for specific users using the properties file format.

```properties
# define default-config param values c3p0.maxPoolSize=30 c3p0.minPoolSize=10 # define params for a user called 'steve' c3p0.user-overrides.steve.maxPoolSize=15 c3p0.user-overrides.steve.minPoolSize=5 # define params for a user called 'ramona' c3p0.user-overrides.ramona.maxPoolSize=50 c3p0.user-overrides.ramona.minPoolSize=20
```

--------------------------------

### Invoke Oracle-specific API via C3P0ProxyConnection

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Demonstrates using reflection to call a static method on an underlying raw connection. Requires casting the connection to C3P0ProxyConnection and using the RAW_CONNECTION token.

```java
C3P0ProxyConnection castCon = (C3P0ProxyConnection) c3p0DataSource.getConnection(); Method m = CLOB.class.getMethod("createTemporary", new Class[]{Connection.class, boolean.class, int.class}); Object[] args = new Object[] {C3P0ProxyConnection.RAW_CONNECTION, Boolean.valueOf( true ), new Integer( 10 )}; CLOB oracleCLOB = (CLOB) castCon.rawConnectionOperation(m, null, args);
```

--------------------------------

### Instantiate PooledDataSource with Named Configuration

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Use a configuration name when creating a data source to apply specific overrides.

```java
ComboPooledDataSource cpds = new ComboPooledDataSource("intergalactoApp");
```

```java
DataSource ds_pooled = DataSources.pooledDataSource( ds_unpooled, "intergalactoApp" );
```

--------------------------------

### Define Named Configurations in HOCON File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define default and named configuration parameters using the HOCON format.

```hocon
c3p0 { maxPoolSize=30 minPoolSize=10 named-configs { intergalactoApp { maxPoolSize=1000 minPoolSize=100 numHelperThreads=50 } littleTeenyApp { maxPoolSize=5 minPoolSize=2 } } }
```

--------------------------------

### Create Pooled DataSources with DataSources Factory

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Builds an unpooled DataSource from a JDBC URL and wraps it into a pooled DataSource using default configurations.

```java
DataSource ds_unpooled = DataSources.unpooledDataSource("jdbc:postgresql://localhost/testdb", "swaldman", "test-password"); DataSource ds_pooled = DataSources.pooledDataSource( ds_unpooled ); // The DataSource ds_pooled is now a fully configured and usable pooled DataSource. // The DataSource is using a default pool configuration, and Postgres' JDBC driver // is presumed to have already been loaded via the jdbc.drivers system property or an // explicit call to Class.forName("org.postgresql.Driver") elsewhere. ...
```

--------------------------------

### Define Per-User Configurations in HOCON File

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Define configuration overrides for specific users using the HOCON format.

```hocon
c3p0 { maxPoolSize=30 minPoolSize=10 user-overrides { steve { maxPoolSize=15 minPoolSize=5 } ramona { maxPoolSize=50 minPoolSize=20 } } }
```

--------------------------------

### Configure Pooled DataSources with Overrides

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Supplies a map of override properties to customize the pooled DataSource configuration.

```java
DataSource ds_unpooled = DataSources.unpooledDataSource("jdbc:postgresql://localhost/testdb", "swaldman", "test-password"); Map overrides = new HashMap(); overrides.put("maxStatements", "200"); //Stringified property values work overrides.put("maxPoolSize", new Integer(50)); //"boxed primitives" also work // create the PooledDataSource using the default configuration and our overrides ds_pooled = DataSources.pooledDataSource( ds_unpooled, overrides ); // The DataSource ds_pooled is now a fully configured and usable pooled DataSource, // with Statement caching enabled for a maximum of up to 200 statements and a maximum // of 50 Connections. ...
```

--------------------------------

### Configure c3p0 DataSource in Tomcat 5.0

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

XML fragment for server.xml to define a c3p0 ComboPooledDataSource within a Tomcat Context.

```xml
<Resource name="jdbc/pooledDS" auth="Container" type="com.mchange.v2.c3p0.ComboPooledDataSource" /> <ResourceParams name="jdbc/pooledDS"> <parameter> <name>factory</name> <value>org.apache.naming.factory.BeanFactory</value> </parameter> <parameter> <name>driverClass</name> <value>org.postgresql.Driver</value> </parameter> <parameter> <name>jdbcUrl</name> <value>jdbc:postgresql://localhost/c3p0-test</value> </parameter> <parameter> <name>user</name> <value>swaldman</value> </parameter> <parameter> <name>password</name> <value>test</value> </parameter> <parameter> <name>minPoolSize</name> <value>5</value> </parameter> <parameter> <name>maxPoolSize</name> <value>15</value> </parameter> <parameter> <name>acquireIncrement</name> <value>5</value> </parameter> </ResourceParams>
```

--------------------------------

### acquireRetryDelay

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Milliseconds, time c3p0 will wait between acquire attempts.

```APIDOC
### Property: acquireRetryDelay

**Default:** 1000

Milliseconds, time c3p0 will wait between acquire attempts.
```

--------------------------------

### Declare J2EE Resource Reference

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Standard web.xml declaration for a DataSource resource reference.

```xml
<resource-ref> <res-ref-name>jdbc/pooledDS</res-ref-name> <res-type>javax.sql.DataSource</res-type> <res-auth>Container</res-auth> </resource-ref>
```

--------------------------------

### acquireRetryAttempts

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Defines how many times c3p0 will retry after a failure to acquire a new Connection from the database before giving up.

```APIDOC
### Property: acquireRetryAttempts

**Default:** 30

Defines how many times c3p0 will retry after a failure to acquire a new Connection from the database before giving up. If this value is less than zero, c3p0 will keep trying to fetch a Connection indefinitely.
```

--------------------------------

### Define c3p0 configuration using HOCON

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Requires the Typesafe config library to be bundled with the application. Configuration can be defined using nested scopes or dot notation.

```hocon
c3p0 { # turn on statement pooling maxStatements=150 # close pooled Connections that go unused for # more than half an hour maxIdleTime=1800 }
```

```hocon
# equivalent to the example above, and # identical to the properties file format. c3p0.maxStatements=150 c3p0.maxIdleTime=1800
```

```hocon
# properties-file-ish specification com.mchange.v2.log.MLog=com.mchange.v2.log.log4j.Log4jMLog # scoped specification of the same com { mchange { v2 { log { MLog="com.mchange.v2.log.log4j.Log4jMLog" } } } }
```

--------------------------------

### attemptResurrectOnCheckin

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

If true, c3p0 will perform an extra Connection test at checkin on Connections it has determined may be broken, and reintegrate any Connections that pass the test.

```APIDOC
### Property: attemptResurrectOnCheckin

**Default:** false

If attemptResurrectOnCheckin is true, c3p0 will perform an extra Connection test at checkin on Connections it has determined may be broken, and reintegrate any Connections that pass the test.
```

--------------------------------

### Configure c3p0 JBoss Service

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

XML configuration for the c3p0 MBean within a JBoss c3p0-service.xml file.

```xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE server> <server> <mbean code="com.mchange.v2.c3p0.jboss.C3P0PooledDataSource" name="jboss:service=C3P0PooledDataSource"> <attribute name="JndiName">java:PooledDS</attribute> <attribute name="JdbcUrl">jdbc:postgresql://localhost/c3p0-test</attribute> <attribute name="DriverClass">org.postgresql.Driver</attribute> <attribute name="User">swaldman</attribute> <attribute name="Password">test</attribute> <!-- Uncomment and set any of the optional parameters below --> <!-- See c3p0's docs for more info. --> <!-- <attribute name="AcquireIncrement">3</attribute> --> <!-- <attribute name="AcquireRetryAttempts">30</attribute> --> <!-- <attribute name="AcquireRetryDelay">1000</attribute> --> <!-- <attribute name="AutoCommitOnClose">false</attribute> --> <!-- <attribute name="AutomaticTestTable"></attribute> --> <!-- <attribute name="BreakAfterAcquireFailure">false</attribute> --> <!-- <attribute name="CheckoutTimeout">0</attribute> --> <!-- <attribute name="ConnectionCustomizerClassName"></attribute> --> <!-- <attribute name="ConnectionTesterClassName"></attribute> --> <!-- <attribute name="Description">A pooled c3p0 DataSource</attribute> --> <!-- <attribute name="DebugUnreturnedConnectionStackTraces">false</attribute> --> <!-- <attribute name="FactoryClassLocation"></attribute> --> <!-- <attribute name="ForceIgnoreUnresolvedTransactions">false</attribute> --> <!-- <attribute name="IdleConnectionTestPeriod">0</attribute> --> <!-- <attribute name="InitialPoolSize">3</attribute> --> <!-- <attribute name="MaxAdministrativeTaskTime">0</attribute> --> <!-- <attribute name="MaxConnectionAge">0</attribute> --> <!-- <attribute name="MaxIdleTime">0</attribute> --> <!-- <attribute name="MaxIdleTimeExcessConnections">0</attribute> --> <!-- <attribute name="MaxPoolSize">15</attribute> --> <!-- <attribute name="MaxStatements">0</attribute> --> <!-- <attribute name="MaxStatementsPerConnection">0</attribute> --> <!-- <attribute name="MinPoolSize">0</attribute> --> <!-- <attribute name="NumHelperThreads">3</attribute> --> <!-- <attribute name="PreferredTestQuery"></attribute> --> <!-- <attribute name="TestConnectionOnCheckin">false</attribute> --> <!-- <attribute name="TestConnectionOnCheckout">false</attribute> --> <!-- <attribute name="UnreturnedConnectionTimeout">0</attribute> --> <depends>jboss:service=Naming</depends> </mbean> </server>
```

--------------------------------

### Configure c3p0 DataSource Resource

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Defines a c3p0 ComboPooledDataSource as a container-managed resource.

```xml
<Resource auth="Container" description="DB Connection" driverClass="com.mysql.jdbc.Driver" maxPoolSize="4" minPoolSize="2" acquireIncrement="1" name="jdbc/TestDB" user="test" password="ready2go" factory="org.apache.naming.factory.BeanFactory" type="com.mchange.v2.c3p0.ComboPooledDataSource" jdbcUrl="jdbc:mysql://localhost:3306/test?autoReconnect=true" />
```

--------------------------------

### Clean up C3P0 PooledDataSource using DataSources.destroy

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Use the static DataSources.destroy method to safely clean up pooled DataSources within a finally block.

```java
DataSource ds_pooled = null; try { DataSource ds_unpooled = DataSources.unpooledDataSource("jdbc:postgresql://localhost/testdb", "swaldman", "test-password"); ds_pooled = DataSources.pooledDataSource( ds_unpooled ); // do all kinds of stuff with that sweet pooled DataSource... } finally { DataSources.destroy( ds_pooled ); }
```

--------------------------------

### Enable PreparedStatement Pooling

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Set the maximum number of statements to enable pooling, which is disabled by default.

```java
cpds.setMaxStatements( 180 );
```

--------------------------------

### Querying PooledDataSource status

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Demonstrates how to cast a JNDI-bound DataSource to a PooledDataSource and retrieve connection metrics.

```java
// fetch a JNDI-bound DataSource InitialContext ictx = new InitialContext(); DataSource ds = (DataSource) ictx.lookup( "java:comp/env/jdbc/myDataSource" ); // make sure it's a c3p0 PooledDataSource if ( ds instanceof PooledDataSource) { PooledDataSource pds = (PooledDataSource) ds; System.err.println("num_connections: " + pds.getNumConnectionsDefaultUser()); System.err.println("num_busy_connections: " + pds.getNumBusyConnectionsDefaultUser()); System.err.println("num_idle_connections: " + pds.getNumIdleConnectionsDefaultUser()); System.err.println(); } else System.err.println("Not a c3p0 PooledDataSource!");
```

--------------------------------

### Access DataSource via JNDI

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Programmatic lookup of a DataSource from the JNDI context within a web application.

```java
InitialContext ic = new InitialContext(); DataSource ds = (DataSource) ic.lookup("java:comp/env/jdbc/pooledDS");
```

--------------------------------

### acquireIncrement

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Determines how many connections at a time c3p0 will try to acquire when the pool is exhausted.

```APIDOC
### Property: acquireIncrement

**Default:** 3

Determines how many connections at a time c3p0 will try to acquire when the pool is exhausted.
```

--------------------------------

### Clean up C3P0 PooledDataSource using close()

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Cast a DataSource to a PooledDataSource to invoke the close() method for manual resource cleanup.

```java
static void cleanup(DataSource ds) throws SQLException { // make sure it's a c3p0 PooledDataSource if ( ds instanceof PooledDataSource) { PooledDataSource pds = (PooledDataSource) ds; pds.close(); } else System.err.println("Not a c3p0 PooledDataSource!"); }
```

--------------------------------

### autoCommitOnClose

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Configuration property for auto-commit behavior on close.

```APIDOC
### Property: autoCommitOnClose

**Default:** false
```

--------------------------------

### Implement a custom IsValidOnlyConnectionTester

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Extends IsValidOnlyConnectionTester to specify a custom timeout for the JDBC4 isValid() method.

```java
package com.mchange.v2.c3p0.example; import com.mchange.v2.c3p0.util.IsValidOnlyConnectionTester; public final class IsValidOnlyConnectionTester30 extends IsValidOnlyConnectionTester { protected int getIsValidTimeout() { return 30; } }
```

--------------------------------

### Clean Up DataSource Resources

Source: https://github.com/swaldman/c3p0/blob/0.14.x/doc/docsrc/index.html

Close the connection pool when it is no longer needed to release resources.

```java
cpds.close();
```
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