Author: fhanik
Date: Thu Jul 2 17:08:50 2009
New Revision: 790684
URL: http://svn.apache.org/viewvc?rev=790684&view=rev
Log:
Add some doco, make shared variables volatile
Modified:
tomcat/trunk/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/ConnectionPool.java
Modified:
tomcat/trunk/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/ConnectionPool.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/ConnectionPool.java?rev=790684&r1=790683&r2=790684&view=diff
==============================================================================
---
tomcat/trunk/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/ConnectionPool.java
(original)
+++
tomcat/trunk/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/ConnectionPool.java
Thu Jul 2 17:08:50 2009
@@ -48,17 +48,28 @@
*/
public class ConnectionPool {
+ /**
+ * Prefix type for JMX registration
+ */
public static final String POOL_JMX_TYPE_PREFIX = "tomcat.jdbc:type=";
- //logger
+ /**
+ * Logger
+ */
protected static Log log = LogFactory.getLog(ConnectionPool.class);
//===============================================================================
// INSTANCE/QUICK ACCESS VARIABLE
//===============================================================================
+ /**
+ * Carries the size of the pool, instead of relying on a queue
implementation
+ * that usually iterates over to get an exact count
+ */
private AtomicInteger size = new AtomicInteger(0);
+
/**
* All the information about the connection pool
+ * These are the properties the pool got instantiated with
*/
private PoolProperties poolProperties;
@@ -76,12 +87,12 @@
/**
* The thread that is responsible for checking abandoned and idle threads
*/
- private PoolCleaner poolCleaner;
+ private volatile PoolCleaner poolCleaner;
/**
* Pool closed flag
*/
- private boolean closed = false;
+ private volatile boolean closed = false;
/**
* Since newProxyInstance performs the same operation, over and over
@@ -95,7 +106,7 @@
private ThreadPoolExecutor cancellator = new
ThreadPoolExecutor(0,1,1000,TimeUnit.MILLISECONDS,new
LinkedBlockingQueue<Runnable>());
/**
- * reference to mbean
+ * reference to the JMX mbean
*/
protected org.apache.tomcat.jdbc.pool.jmx.ConnectionPool jmxPool = null;
@@ -119,6 +130,14 @@
}
+ /**
+ * Retrieves a Connection future. If a connection is not available, one
can block using future.get()
+ * until a connection has become available.
+ * If a connection is not retrieved, the Future must be cancelled in order
for the connection to be returned
+ * to the pool.
+ * @return
+ * @throws SQLException
+ */
public Future<Connection> getConnectionAsync() throws SQLException {
if (idle instanceof FairBlockingQueue) {
Future<PooledConnection> pcf =
((FairBlockingQueue<PooledConnection>)idle).pollAsync();
@@ -130,7 +149,7 @@
/**
* Borrows a connection from the pool
- * @return Connection - a java.sql.Connection reflection proxy, wrapping
the underlying object.
+ * @return Connection - a java.sql.Connection/javax.sql.PooledConnection
reflection proxy, wrapping the underlying object.
* @throws SQLException
*/
public Connection getConnection() throws SQLException {
@@ -180,6 +199,10 @@
return busy.size();
}
+ /**
+ * Returns the number of idle connections
+ * @return
+ */
public int getIdle() {
return idle.size();
}
@@ -197,7 +220,11 @@
//===============================================================================
+ /**
+ * configures a pooled connection as a proxy
+ */
protected Connection setupConnection(PooledConnection con) throws
SQLException {
+ //fetch previous interceptor proxy
JdbcInterceptor handler = con.getHandler();
if (handler==null) {
//build the proxy handler
@@ -252,6 +279,10 @@
return proxyClassConstructor;
}
+ /**
+ * If the connection pool gets garbage collected, lets make sure we clean
up
+ * and close all the connections
+ */
@Override
protected void finalize() throws Throwable {
close(true);
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