1 to 1 Mapping using Indirection is causing a StackOverflowError exception

Question

I am trying to map a database column that contains a BLOB (i.e. PDF) to a persistent object's attribute that will contain the BLOB as a "1 to 1 mapping" utilizing "Indirection".
The type of the persistent object's attribute is ValueHolderInterface and it is initialized as ValueHolder in the object's constructor.
The column that contains the BLOB is not a primary key therefore in the "Table Reference" tab of the TopLink Workbench I use the database table's primary key for the "Source Field" and "Target Field".
The mapping seems find until I test the code. When the code is executed a java.lang.StackOverflowError exception is thrown in the following method ServerSession(DatabaseSession).initializeDescriptors(Hashtable).
In this scenario I am using "indirection" for obvious reasons. I want to have the ability to retrieve all the data in the row(s) except the PDF(s) so I can build a list for the user to choose from. If the user makes a selection I want to then go and retrieve the PDF via the persistent object's get/set methods that utilize the ValueHolder's interface methods getValue/setValue.
Does anyone have any idea why this exception is being thrown and anyway to fix it? ANY help would be greatly appreciated. I included the stack trace below.
The IDE our company is using at the moment is IBM's VisualAge for Java 4.0....don't ask.
Debugger Stack Trace Report:
Thread[P=359251:O=0:CT,5,main] (Alive)
Uncaught exception (java.lang.StackOverflowError)
     ServerSession(DatabaseSession).initializeDescriptors(Hashtable)
          this=(oracle.toplink.threetier.ServerSession) ServerSession(
     DatabaseAccessor(connected)
     OraclePlatform)
          arg_1=(java.util.Hashtable) {class com.nwprov.provconnect.qss.domain.QssStatementTypes=Descriptor(com.nwprov.provconnect.qss.domain.QssStatementTypes --> [DatabaseTable(QSS_STATEMENT_TYPES)]), class com.nwprov.provconnect.qss.domain.QssTransactionTypes=Descriptor(com.nwprov.provconnect.qss.domain.QssTransactionTypes --> [DatabaseTable(QSS_TRANSACTION_TYPES)]), class com.nwprov.provconnect.qss.domain.QssTransactions=Descriptor(com.nwprov.provconnect.qss.domain.QssTransactions --> [DatabaseTable(QSS_TRANSACTIONS)]), class com.nwprov.provconnect.qss.domain.QssPolicyStatements=Descriptor(com.nwprov.provconnect.qss.domain.QssPolicyStatements --> [DatabaseTable(QSS_POLICY_STATEMENTS)]), class com.nwprov.provconnect.qss.domain.QssSubaccountPerformance=Descriptor(com.nwprov.provconnect.qss.domain.QssSubaccountPerformance --> [DatabaseTable(QSS_SUBACCOUNT_PERFORMANCE)])}
     ServerSession(DatabaseSession).initializeDescriptors()
          this=(oracle.toplink.threetier.ServerSession) ServerSession(
     DatabaseAccessor(connected)
     OraclePlatform)
     ServerSession(DatabaseSession).login()
          this=(oracle.toplink.threetier.ServerSession) ServerSession(
     DatabaseAccessor(connected)
     OraclePlatform)
     SessionManager.getSession(XMLLoader, String, ClassLoader, boolean, boolean)
          this=(oracle.toplink.tools.sessionmanagement.SessionManager) oracle.toplink.tools.sessionmanagement.SessionManager@5172
          arg_1=(oracle.toplink.tools.sessionconfiguration.XMLLoader) oracle.toplink.tools.sessionconfiguration.XMLLoader@146c
          arg_2=(java.lang.String) qss
          arg_3=(java.lang.ClassLoader) sun.misc.Launcher$AppClassLoader@51e4
          arg_4=(boolean) true
          arg_5=(boolean) false
     SessionManager.getSession(XMLLoader, String, ClassLoader)
          this=(oracle.toplink.tools.sessionmanagement.SessionManager) oracle.toplink.tools.sessionmanagement.SessionManager@5172
          arg_1=(oracle.toplink.tools.sessionconfiguration.XMLLoader) oracle.toplink.tools.sessionconfiguration.XMLLoader@146c
          arg_2=(java.lang.String) qss
          arg_3=(java.lang.ClassLoader) sun.misc.Launcher$AppClassLoader@51e4
     SessionManager.getSession(String)
          this=(oracle.toplink.tools.sessionmanagement.SessionManager) oracle.toplink.tools.sessionmanagement.SessionManager@5172
          arg_1=(java.lang.String) qss
     SessionSingleton.initializeSession(String)
          this=(com.nwprov.toplink.SessionSingleton) com.nwprov.toplink.SessionSingleton@4e0
          projectName=(java.lang.String) qss
     SessionSingleton.getSession(String)
          this=(com.nwprov.toplink.SessionSingleton) com.nwprov.toplink.SessionSingleton@4e0
          projectName=(java.lang.String) qss
          serverSession=(oracle.toplink.threetier.ServerSession) null
     PerformancePdfRetriever(TopLinkPdfAccessor).queryForPdf(Expression)
          this=(com.nwprov.provconnect.qss.statement.PerformancePdfRetriever) [email protected]
          topLinkExpression=(oracle.toplink.expressions.Expression)
Logical operator AND
Logical operator AND
Relation operator =
Query Key legacyProductCode
Base QUERY OBJECT
Constant 00001
Relation operator =
Query Key statementPerformanceDate
Base QUERY OBJECT
Constant 2003-07-01
Relation operator =
Query Key legacyCoCode
Base QUERY OBJECT
Constant 01
     PerformancePdfRetriever.getPdf(String, Date, String)
          this=(com.nwprov.provconnect.qss.statement.PerformancePdfRetriever) [email protected]
          legacyProdCode=(java.lang.String) 00001
          stmntPrfmncDate=(java.sql.Date) 2003-07-01
          legacyCoCode=(java.lang.String) 01
          pdfTopLinkObject=(com.nwprov.provconnect.qss.domain.IPdf) com.nwprov.provconnect.qss.domain.QssSubaccountPerformance@28ea
          expression=(oracle.toplink.expressions.Expression)
Logical operator AND
Logical operator AND
Relation operator =
Query Key legacyProductCode
Base QUERY OBJECT
Constant 00001
Relation operator =
Query Key statementPerformanceDate
Base QUERY OBJECT
Constant 2003-07-01
Relation operator =
Query Key legacyCoCode
Base QUERY OBJECT
Constant 01
     Object.Doit()
          retrievePerformancePdfHelper=(com.nwprov.provconnect.qss.statement.PerformancePdfRetriever) [email protected]
          legacyProdCode=(java.lang.String) 00001
          statementPerfDate=(java.sql.Date) 2003-07-01
          legacyCoCode=(java.lang.String) 01

Answer 1

Hello Don,
Let me preface by saying thanks for being a brave soul to assist with this.
Is there anything in the output leading up to the exception? No. There isn't any other output because the part of the code that I am unit testing just performs the function of retrieving the BLOB (i.e. PDF) from the database. I used hard coded values for the multi-value primary key in the driver.
Is there some sort of obvious recursive query going on? No, not from what I can tell.
Stack overflows usually result from bi-directional relationships where caching is turned off. If this is the case, use a Weak cache.This is not a bi-directinal relationship so let me provide you with details that lead up to the stack overflow.
Details:
- An expression is built using the hard coded values for the primary key:
     Expression exp1 = builder.get(LEGACY_PRODUCT_CODE).equal(legacyProdCode);
     Expression exp2 = builder.get(STATEMENT_PERFORMANCE_DATE).equal(stmntPrfmncDate);
     Expression exp3 = builder.get(LEGACY_CO_CODE).equal(legacyCoCode);
     Expression finalExp = exp1.and(exp2);
     finalExpression = finalExpression.and(exp3);
- Expression is being executed:
Session session = SessionSingleton.getInstance().getSession(SESSION_NAME);
Collection pdfTopLinkObjects = new Vector();
          pdfTopLinkObjects = session.readAllObjects(queryObject.getClass(), topLinkExpression);
- Returned Collection is investigated & utilized for values using Iterator
BTW, in my first post there was an error. Here is the correction:
The column that contains the BLOB is not a primary key therefore in the "Table Reference" tab of the TopLink Workbench I tried both os these situations:
1. Used the database table's primary key for the "Source Field" and "Target Field".
2. Used the database table's column that stores the BLOB (i.e. PDF) for the "Source Field" and "Target Field".
Am I using the write type of mapping for this? As stated before I am currently using "one to one with Indirection" or should I be using something else.
Dan, is this enough info to help diagnose the problem? I hope so :-(