private BacklogStatus getBacklogStatus()

in src/main/java/org/apache/sling/discovery/commons/providers/spi/base/OakBacklogClusterSyncService.java [180:260]
54 lines of code
11 McCabe index (conditional complexity)

    private BacklogStatus getBacklogStatus(BaseTopologyView view) {
        logger.trace("getBacklogStatus: start");
        ResourceResolver resourceResolver = null;
        try{
            resourceResolver = getResourceResolver();
            DiscoveryLiteDescriptor descriptor =
                    DiscoveryLiteDescriptor.getDescriptorFrom(resourceResolver);

            // backlog-free means:
            // 1) 'deactivating' must be empty
            //     (otherwise we indeed have a backlog)
            // 2) all active ids of the descriptor must have a mapping to slingIds
            //     (otherwise the init failed or is pending for some instance(s))
            // 3) all 'active' instances must be in the view
            //     (otherwise discovery lite might not yet consider
            //     an instance dead but discovery-service does)
            // instead what is fine from a backlog point of view
            // * instances in the view but listed as 'inactive'
            //     (this might be the case for just-started instances)
            // * instances in the view but not contained in the descriptor at all
            //     (this might be the case for just-started instances)

            int[] activeIds = descriptor.getActiveIds();
            int[] deactivatingIds = descriptor.getDeactivatingIds();
            // we're not worried about 'inactive' ones - as that could
            // be a larger list filled with legacy entries too
            // plus once the instance is inactive there's no need to
            // check anything further - that one is then backlog-free

            // 1) 'deactivating' must be empty
            if (deactivatingIds.length!=0) {
                logSilencer.infoOrDebug("getBacklogStatus-hasBacklog-" + view.toShortString(),
                        "getBacklogStatus: there are deactivating instances: "+Arrays.toString(deactivatingIds));
                return BacklogStatus.HAS_BACKLOG;
            }

            ClusterView cluster = view.getLocalInstance().getClusterView();
            LocalClusterView localCluster = null;
            if (cluster instanceof LocalClusterView) {
                localCluster = (LocalClusterView)cluster;
            }
            Set<String> slingIds = new HashSet<>();
            for (InstanceDescription instance : cluster.getInstances()) {
                slingIds.add(instance.getSlingId());
            }

            for(int i=0; i<activeIds.length; i++) {
                int activeId = activeIds[i];
                if (localCluster != null && localCluster.isPartiallyStarted(activeId)) {
                    // ignore this one then
                    continue;
                }
                String slingId = idMapService.toSlingId(activeId, resourceResolver);
                // 2) all ids of the descriptor must have a mapping to slingIds
                if (slingId == null) {
                    logSilencer.infoOrDebug("getBacklogStatus-undefined-" + view.toShortString(),
                            "getBacklogStatus: no slingId found for active id: "+activeId);
                    return BacklogStatus.UNDEFINED;
                }
                // 3) all 'active' instances must be in the view
                if (!slingIds.contains(slingId)) {
                    logSilencer.infoOrDebug("getBacklogStatus-hasBacklog-" + view.toShortString(),
                            "getBacklogStatus: active instance's ("+activeId+") slingId ("+slingId+") not found in cluster ("+cluster+")");
                    return BacklogStatus.HAS_BACKLOG;
                }
            }

            logSilencer.infoOrDebug("getBacklogStatus-" + view.toShortString(),
                    "getBacklogStatus: no backlog (anymore)");
            return BacklogStatus.NO_BACKLOG;
        } catch(Exception e) {
            logSilencer.infoOrDebug("getBacklogStatus-undefined-" + view.toShortString(),
                    "getBacklogStatus: failed to determine backlog status: "+e);
            return BacklogStatus.UNDEFINED;
        } finally {
            logger.trace("getBacklogStatus: end");
            if (resourceResolver!=null) {
                resourceResolver.close();
            }
        }
    }