Composite PK auto-generation (compound identity support)

[andyjefferson]

The org.datanucleus.enhancer.asm.primarykey.PrimaryKeyGenerator class has several TODOs that indicate support for compound identity is missing. This would be nice to have so I'm just opening a bug to request/track the additional feature.

If this isn't liable to coming anytime soon, I'd recommend that an error/warning be spit out during enhancement to mention that these classes aren't supported. As things stand now, this looks like it works up until runtime, when an exception similar to the following is thrown:
java.lang.NoSuchFieldError: thresholdRule
at com.knowledgecc.cxmlchecker.threshold.ThresholdRuleValidator_PK.hashCode(Unknown Source)
at java.util.HashMap.put(HashMap.java:418)
at org.datanucleus.util.ReferenceValueMap.put(ReferenceValueMap.java:145)
at org.datanucleus.cache.SoftRefCache.put(SoftRefCache.java:51)
at org.datanucleus.ObjectManagerImpl.putObjectIntoCache(ObjectManagerImpl.java:3874)
at org.datanucleus.ObjectManagerImpl.replaceObjectId(ObjectManagerImpl.java:3821)
at org.datanucleus.jdo.state.JDOStateManagerImpl.setIdentity(JDOStateManagerImpl.java:941)
at org.datanucleus.jdo.state.JDOStateManagerImpl.initialiseForPersistentNew(JDOStateManagerImpl.java:470)
at org.datanucleus.state.StateManagerFactory.newStateManagerForPersistentNew(StateManagerFactory.java:151)
at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1427)
at org.datanucleus.ObjectManagerImpl.persistObject(ObjectManagerImpl.java:1241)
at org.datanucleus.jdo.JDOPersistenceManager.jdoMakePersistent(JDOPersistenceManager.java:655)
at org.datanucleus.jdo.JDOPersistenceManager.makePersistent(JDOPersistenceManager.java:680)
at com.knowledgecc.entity.ThresholdRuleValidatorModelTest.saveValidator(ThresholdRuleValidatorModelTest.java:333)
at com.knowledgecc.entity.ThresholdRuleValidatorModelTest.testModelForSavedInstance(ThresholdRuleValidatorModelTest.java:94)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)