Thanks!
> Date: Wed, 17 Sep 2008 08:01:01 -0400
> From: [EMAIL PROTECTED]
> To: users@tomcat.apache.org
> Subject: Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keep
> increasing....
>
> A static method can't have access to class instance variables. You
> could make it static, but it shouldn't reference any variables it didn't
> locally declare:
>
> /**
> * Gets a [EMAIL PROTECTED] DataSource} for database connection usage.
> * @return The datasource for database connection.
> * @throws SQLException
> */
> public static DataSource getDataSource() throws SQLException {
> Datasource ds = null ;
> try {
> Context initContext = new InitialContext();
> ds = (DataSource)initContext.lookup("java:/comp/env/jdbc/myDB");
> initContext.close();
> return ds;
> } catch (final NamingException e) {
> e.printStackTrace();
> throw new RuntimeException("Java naming exception when
> getting connection from tomcat pool: " + e.getMessage());
> }
> }
>
> --David
>
>
> sinoea kaabi wrote:
> > Just a question here,
> > I am using a Data class to retrieve the datasource
> >
> > public class Data {
> >
> > /**
> > * Gets a [EMAIL PROTECTED] DataSource} for database connection usage.
> > * @return The datasource for database connection.
> > * @throws SQLException
> > */
> > public static DataSource getDataSource() throws SQLException {
> > if (ds == null) {
> > DATASOURCE.info("DataSource is NULL ");
> > MANY_CONNECTIONS.info("DataSource is NULL ");
> > try {
> > final Context initContext = new
> > InitialContext();
> > ds =
> > (BasicDataSource)initContext.lookup("java:/comp/env/jdbc/myDB");
> > initContext.close();
> > logDataSource(ds);
> > return ds;
> > } catch (final NamingException e) {
> > e.printStackTrace();
> > throw new RuntimeException("Java naming
> > exception when getting connection from tomcat pool: " + e.getMessage());
> > }
> > } else {
> > logDataSource(ds);
> > return ds;
> > }
> > }
> >
> > }
> >
> >
> > Collection branches = new BranchData().loadBranches(Data.getDataSource(),
> > 1);
> >
> >
> > Can the getDataSource method be static?
> >
> > Thanks,
> > Sinoea
> >
> >
> >> From: [EMAIL PROTECTED]
> >> To: users@tomcat.apache.org
> >> Subject: Re: Tomcat 5.5, JNDI Connection Pooling, Active connections keep
> >> increasing....
> >> Date: Wed, 17 Sep 2008 12:25:17 +0200
> >>
> >>
> >> ----- Original Message -----
> >> From: "sinoea kaabi"
> >> To: "Tomcat Users List"
> >> Sent: Wednesday, September 17, 2008 11:31 AM
> >> Subject: RE: Tomcat 5.5, JNDI Connection Pooling, Active connections keep
> >> increasing....
> >>
> >>
> >>
> >> Thanks,
> >> First I will try to close resources before returning.
> >>
> >> Although I am sure that the finally blocks are reached, since I use logging
> >> in the last finally block and the log is
> >> outputted.
> >>
> >> try {
> >>
> >> } finally {
> >> connection.close();
> >> Data.logConnection(connection); // this is logged
> >> }
> >>
> >> But I'll give it a try anyway.
> >>
> >> Object object = null;
> >> try {
> >>
> >> } finally {
> >> close resources..
> >> }
> >> return object;
> >>
> >>
> >> The static methods are not thread-safe you say!
> >>
> >> So, what exactly does it mean when we say that Tomcat is thread safe for
> >> requests.
> >> Tomcat creates a new thread for each request, so somehow my static methods
> >> are then thread safe (incdirectly, since it is managed by Tomcat).
> >>
> >> Request A> new Thread A> using my static method for loadBranches(...)
> >> Request B> new Thread B> using my static method for loadBranches(...)
> >>
> >> Thread B must wait until Thread A is done.
> >>
> >> Since threads are managed by tomcat, no thread should be able to use a
> >> static method that is used by another thread.
> >>
> >> Or in fact, you must be right, should I declare them synchronized?
> >>
> >> public static synchronized loadBranches(...)
> >>
> >> Thanks,
> >> Sinoea
> >>
> >> =====================================
> >>
> >> Yes your finally blocks are working.... I checked that... the book is right
> >> ;)
> >>
> >>
> >> On threading..... No.... just make the class *non* static....
> >>
> >> Collection branches = *NEW*
> >> BranchData().loadBranches(Data.getDataSource(), 1);
> >>
> >> so now each thread has its own class.....
> >>
> >> I imagine thats tomcats pool is already thread safe...
> >>
> >> synchronized will work... but its a bottle neck... it will make tomcat Q...
> >> and there is a setting in tomcat somewhere where one can make it single
> >> threaded... but again it will slow it down... you only use that when a
> >> coder
> >> has cocked up ;)
> >>
> >> In threading the thing to watch is those global variables... so without
> >> seeing your actual code its difficult to spot problems...
> >> Thread safety is more of an art than a science...
> >>
> >> New should do it because every thread is getting its own class... so a
> >> class
> >> is isolated, the connection and everything else is inside it... and they
> >> cant mess with each other... in theory... if there are no shared globals...
> >>
> >> So I think whats happening in your static class is something like this...
> >>
> >> Thread 1 opens connection 1.... inside class
> >> Thread 2 open connection 2.... also inside class
> >>
> >> Close connection 2
> >> Close connection 2
> >>
> >> ie same connection is no closed twice and connection 1 slips out... that
> >> wont happen if the class in not static...
> >>
> >> .... I think ;)
> >>
> >> have fun...
> >> ---------------------------------------------------------------------------
> >> HARBOR : http://www.kewlstuff.co.za/index.htm
> >> The most powerful application server on earth.
> >> The only real POJO Application Server.
> >> See it in Action : http://www.kewlstuff.co.za/cd_tut_swf/whatisejb1.htm
> >> ---------------------------------------------------------------------------
> >>
> >>
> >> ---------------------------------------------------------------------
> >> To start a new topic, e-mail: users@tomcat.apache.org
> >> To unsubscribe, e-mail: [EMAIL PROTECTED]
> >> For additional commands, e-mail: [EMAIL PROTECTED]
> >>
> >>
> >
> > _________________________________________________________________
> > Win New York holidays with Kellogg’s & Live Search
> > http://clk.atdmt.com/UKM/go/111354033/direct/01/
> > ---------------------------------------------------------------------
> > To start a new topic, e-mail: users@tomcat.apache.org
> > To unsubscribe, e-mail: [EMAIL PROTECTED]
> > For additional commands, e-mail: [EMAIL PROTECTED]
> >
> >
>
>
> ---------------------------------------------------------------------
> To start a new topic, e-mail: users@tomcat.apache.org
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
_________________________________________________________________
Make a mini you and download it into Windows Live Messenger
http://clk.atdmt.com/UKM/go/111354029/direct/01/
