Yes, it is for the same reason, to management resource leaking in a better way. Java 7 finally has added this long-waited language feature. I’ve been using JRE 7 with CloudStack for a while and didn’t see any alerted issues.
Kelven On 1/6/14, 3:34 PM, "Chiradeep Vittal" <chiradeep.vit...@citrix.com> wrote: >Yes, there was another discussion here: >http://markmail.org/thread/uf6bxab6u4z4fmrp > > > >On 1/6/14 3:18 PM, "Kelven Yang" <kelven.y...@citrix.com> wrote: > >>Java 7 has been around for some time now. I strongly suggest CloudStack >>to adopt Java 7 as early as possible, the reason I feel like to raise the >>issue is from the some of practicing with the new DB transaction pattern, >>as following example shows. The new Transaction pattern uses anonymous >>class to beautify the code structure, but in the mean time, it will >>introduce a couple runtime costs >> >> 1. Anonymous class introduces a ³captured context², information >>exchange between the containing context and the anonymous class >>implementation context has either to go through with mutable passed-in >>parameter or returned result object, in the following example, without >>changing basic Transaction framework, I have to exchange through returned >>result with an un-typed array. This has a few implications at run time, >>basically with each call of the method, it will generate two objects to >>the heap. Depends on how frequently the involved method will be called, >>it may introduce quite a burden to java GC process >> 2. Anonymous class captured context also means that there will be more >>hidden classes be generated, since each appearance of the anonymous class >>implementation will have a distance copy of its own as hidden class, it >>will generally increase our permanent heap usage, which is already pretty >>huge with current CloudStack code base. >> >>Java 7 has a language level support to address the issues in a cheaper >>way that our current DB Transaction code pattern is trying to solve. >>http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceCl >>o >>se.html. So, time to adopt Java 7? >> >> public Outcome<VirtualMachine> startVmThroughJobQueue(final String >>vmUuid, >> final Map<VirtualMachineProfile.Param, Object> params, >> final DeploymentPlan planToDeploy) { >> >> final CallContext context = CallContext.current(); >> final User callingUser = context.getCallingUser(); >> final Account callingAccount = context.getCallingAccount(); >> >> final VMInstanceVO vm = _vmDao.findByUuid(vmUuid); >> >> >> Object[] result = Transaction.execute(new >>TransactionCallback<Object[]>() { >> @Override >> public Object[] doInTransaction(TransactionStatus status) { >> VmWorkJobVO workJob = null; >> >> _vmDao.lockRow(vm.getId(), true); >> List<VmWorkJobVO> pendingWorkJobs = >>_workJobDao.listPendingWorkJobs(VirtualMachine.Type.Instance, >> vm.getId(), VmWorkStart.class.getName()); >> >> if (pendingWorkJobs.size() > 0) { >> assert (pendingWorkJobs.size() == 1); >> workJob = pendingWorkJobs.get(0); >> } else { >> workJob = new VmWorkJobVO(context.getContextId()); >> >> >>workJob.setDispatcher(VmWorkConstants.VM_WORK_JOB_DISPATCHER); >> workJob.setCmd(VmWorkStart.class.getName()); >> >> workJob.setAccountId(callingAccount.getId()); >> workJob.setUserId(callingUser.getId()); >> workJob.setStep(VmWorkJobVO.Step.Starting); >> workJob.setVmType(vm.getType()); >> workJob.setVmInstanceId(vm.getId()); >> >>workJob.setRelated(AsyncJobExecutionContext.getOriginJobContextId()); >> >> // save work context info (there are some duplications) >> VmWorkStart workInfo = new >>VmWorkStart(callingUser.getId(), callingAccount.getId(), vm.getId(), >>VirtualMachineManagerImpl.VM_WORK_JOB_HANDLER); >> workInfo.setPlan(planToDeploy); >> workInfo.setParams(params); >> workJob.setCmdInfo(VmWorkSerializer.serialize(workInfo)); >> >> _jobMgr.submitAsyncJob(workJob, >>VmWorkConstants.VM_WORK_QUEUE, vm.getId()); >> } >> >> return new Object[] {workJob, new Long(workJob.getId())}; >> } >> }); >> >> final long jobId = (Long)result[1]; >> AsyncJobExecutionContext.getCurrentExecutionContext().joinJob(jobId); >> >> return new VmStateSyncOutcome((VmWorkJobVO)result[0], >> VirtualMachine.PowerState.PowerOn, vm.getId(), null); >> } >> >> >>Kelven >
