Re: Object references... Fetched in a separate thread?
Hello, Rainer. I believe that you misunderstand. The behaviour that I described is exactly the opposite of what you seem to suggest. I don't suffer my productCategory reference becoming null because I sleep for 50 milliseconds. Just the opposite... I have to sleep for 50 milliseconds before my productCategory reference becomes valid. Rainer Klute [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hm, reminds me of the problem I encounter with the cache. Depending on which cache implementation I use my application behaves differently. In your case, could it be the garbage collector removes your ProductCategory instance while your main thread is asleep? Best regards Rainer Klute Rainer Klute IT-Consulting GmbH Dipl.-Inform. Rainer Klute E-Mail: [EMAIL PROTECTED] Körner Grund 24 Telefon: +49 172 2324824 D-44143 Dortmund Telefax: +49 231 5349423 On Sat, 21 Feb 2004 00:18:55 -0700 Sean Dockery [EMAIL PROTECTED] wrote: Hello there. I've had a curious experience recently with OJB, and I was wondering if someone could confirm my speculations about the behaviour. Suppose I have two objects... Product and ProductCategory. The Product object carries both a productCategoryId field as well as a reference field productCategory which is declared as auto-retrieve in my class descriptor. Consider the following code segment... Transaction tx = implementation.newTransaction(); tx.begin(); PersistenceBroker broker = ((HasBroker) tx).getBroker(); Product template = new Product(); template.setId(productId); Identity identity = new Identity(template, broker); Product result = (Product) broker.getObjectByIdentity(identity); tx.commit(); // Thread.sleep(50); System.out.println(result.getProductCategory().getName()); Curiously, I sometimes experience a null pointer exception because result.getProductCategory() return null. When I uncomment the Threat.sleep() call, the null pointer exception never happens. This seems to suggest that the productCategory reference is being loaded by another thread. Is this the case or can someone explain why Product.getProductCategory returns null for me sometimes when I first retrieve the Product object? Thanks for your time... - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Object references... Fetched in a separate thread?
Hi Sean, I'm nearly sure that OJB never starts new threads by its own. AFAIK only the commons-DBCP api starts a new thread (if you enable it) to monitor/manage the used connections (used in a ConnectionFactory implementation, but per default OJB use it's own connection pool). maintaining uses an opaque persistence framework that extends OJB; it Do this framework use unchanged OJB sources? regards, Armin Sean Dockery wrote: Unfortunately, I'm stuck on version 0.9.8. The application that I'm maintaining uses an opaque persistence framework that extends OJB; it creates classes explicitly which have disappeared between 0.9.8 and 1.0RC4. But because I'm using PB calls directly, I'm certain that this problem has nothing to do with the opaque persistence framework. (The value of this software company's persistence framework is dubious; I'll be glad when we can rid ourselves of it.) Antonio Gallardo [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hi Sean: AFAIK, this would not happen. BTW, what version are you using? Best Regards, Antonio Gallardo Sean Dockery dijo: Hello there. I've had a curious experience recently with OJB, and I was wondering if someone could confirm my speculations about the behaviour. Suppose I have two objects... Product and ProductCategory. The Product object carries both a productCategoryId field as well as a reference field productCategory which is declared as auto-retrieve in my class descriptor. Consider the following code segment... Transaction tx = implementation.newTransaction(); tx.begin(); PersistenceBroker broker = ((HasBroker) tx).getBroker(); Product template = new Product(); template.setId(productId); Identity identity = new Identity(template, broker); Product result = (Product) broker.getObjectByIdentity(identity); tx.commit(); // Thread.sleep(50); System.out.println(result.getProductCategory().getName()); Curiously, I sometimes experience a null pointer exception because result.getProductCategory() return null. When I uncomment the Threat.sleep() call, the null pointer exception never happens. This seems to suggest that the productCategory reference is being loaded by another thread. Is this the case or can someone explain why Product.getProductCategory returns null for me sometimes when I first retrieve the Product object? Thanks for your time... - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Object references... Fetched in a separate thread?
Armin Waibel [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hi Sean, Hello, Armin. I'm nearly sure that OJB never starts new threads by its own. AFAIK only the commons-DBCP api starts a new thread (if you enable it) to monitor/manage the used connections (used in a ConnectionFactory implementation, but per default OJB use it's own connection pool). I looked in the OJB.properties file and found the following... ConnectionFactoryClass=org.apache.ojb.broker.accesslayer.ConnectionFactoryP ooledImpl ...and the line with DBCP is commented out, so it doesn't look like DBCP is the culprit. maintaining uses an opaque persistence framework that extends OJB; it Do this framework use unchanged OJB sources? I can't know for sure, but I doubt it. The framework was licensed with the application that was produced by this consulting company (that is, the same company that produced this framework wrote a custom software application based on their framework). Having worked with their source code for the application, I don't think that they would be capable of that. I've been working on this problem off and on for about a week now; if anyone knows of a solution, please post it here. If I find the solution, I'll do the same. Thanks. regards, Armin Sean Dockery wrote: Unfortunately, I'm stuck on version 0.9.8. The application that I'm maintaining uses an opaque persistence framework that extends OJB; it creates classes explicitly which have disappeared between 0.9.8 and 1.0RC4. But because I'm using PB calls directly, I'm certain that this problem has nothing to do with the opaque persistence framework. (The value of this software company's persistence framework is dubious; I'll be glad when we can rid ourselves of it.) Antonio Gallardo [EMAIL PROTECTED] wrote in message news:[EMAIL PROTECTED] Hi Sean: AFAIK, this would not happen. BTW, what version are you using? Best Regards, Antonio Gallardo Sean Dockery dijo: Hello there. I've had a curious experience recently with OJB, and I was wondering if someone could confirm my speculations about the behaviour. Suppose I have two objects... Product and ProductCategory. The Product object carries both a productCategoryId field as well as a reference field productCategory which is declared as auto-retrieve in my class descriptor. Consider the following code segment... Transaction tx = implementation.newTransaction(); tx.begin(); PersistenceBroker broker = ((HasBroker) tx).getBroker(); Product template = new Product(); template.setId(productId); Identity identity = new Identity(template, broker); Product result = (Product) broker.getObjectByIdentity(identity); tx.commit(); // Thread.sleep(50); System.out.println(result.getProductCategory().getName()); Curiously, I sometimes experience a null pointer exception because result.getProductCategory() return null. When I uncomment the Threat.sleep() call, the null pointer exception never happens. This seems to suggest that the productCategory reference is being loaded by another thread. Is this the case or can someone explain why Product.getProductCategory returns null for me sometimes when I first retrieve the Product object? Thanks for your time... - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Object references... Fetched in a separate thread?
Hi Sean: AFAIK, this would not happen. BTW, what version are you using? Best Regards, Antonio Gallardo Sean Dockery dijo: Hello there. I've had a curious experience recently with OJB, and I was wondering if someone could confirm my speculations about the behaviour. Suppose I have two objects... Product and ProductCategory. The Product object carries both a productCategoryId field as well as a reference field productCategory which is declared as auto-retrieve in my class descriptor. Consider the following code segment... Transaction tx = implementation.newTransaction(); tx.begin(); PersistenceBroker broker = ((HasBroker) tx).getBroker(); Product template = new Product(); template.setId(productId); Identity identity = new Identity(template, broker); Product result = (Product) broker.getObjectByIdentity(identity); tx.commit(); // Thread.sleep(50); System.out.println(result.getProductCategory().getName()); Curiously, I sometimes experience a null pointer exception because result.getProductCategory() return null. When I uncomment the Threat.sleep() call, the null pointer exception never happens. This seems to suggest that the productCategory reference is being loaded by another thread. Is this the case or can someone explain why Product.getProductCategory returns null for me sometimes when I first retrieve the Product object? Thanks for your time... - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Object references... Fetched in a separate thread?
Hm, reminds me of the problem I encounter with the cache. Depending on which cache implementation I use my application behaves differently. In your case, could it be the garbage collector removes your ProductCategory instance while your main thread is asleep? Best regards Rainer Klute Rainer Klute IT-Consulting GmbH Dipl.-Inform. Rainer Klute E-Mail: [EMAIL PROTECTED] Körner Grund 24 Telefon: +49 172 2324824 D-44143 Dortmund Telefax: +49 231 5349423 On Sat, 21 Feb 2004 00:18:55 -0700 Sean Dockery [EMAIL PROTECTED] wrote: Hello there. I've had a curious experience recently with OJB, and I was wondering if someone could confirm my speculations about the behaviour. Suppose I have two objects... Product and ProductCategory. The Product object carries both a productCategoryId field as well as a reference field productCategory which is declared as auto-retrieve in my class descriptor. Consider the following code segment... Transaction tx = implementation.newTransaction(); tx.begin(); PersistenceBroker broker = ((HasBroker) tx).getBroker(); Product template = new Product(); template.setId(productId); Identity identity = new Identity(template, broker); Product result = (Product) broker.getObjectByIdentity(identity); tx.commit(); // Thread.sleep(50); System.out.println(result.getProductCategory().getName()); Curiously, I sometimes experience a null pointer exception because result.getProductCategory() return null. When I uncomment the Threat.sleep() call, the null pointer exception never happens. This seems to suggest that the productCategory reference is being loaded by another thread. Is this the case or can someone explain why Product.getProductCategory returns null for me sometimes when I first retrieve the Product object? Thanks for your time... - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
