public void handleTopologyEvent()

in src/main/java/org/apache/sling/discovery/oak/TopologyWebConsolePlugin.java [587:725]
130 lines of code
28 McCabe index (conditional complexity)

    public void handleTopologyEvent(final TopologyEvent event) {
        if (getBundleContext() == null) {
            logger.info("handleTopologyEvent: ignoring event when not activated: " + event);
            return;
        }
        if (event.getType() == Type.PROPERTIES_CHANGED) {
            this.currentView = event.getNewView();

            StringBuilder sb = new StringBuilder();
            InstancesDiff instanceDiff = new InstancesDiff(event.getOldView(), event.getNewView());

            // there shouldn't be any instances added, but for paranoia reason:
            Collection<InstanceDescription> added = instanceDiff.added().get();
            if (!added.isEmpty()) {
                sb.append("instances were added:");
                for (InstanceDescription instance : added) {
                    sb.append(" ");
                    sb.append(instance.getSlingId());
                }
                sb.append(".");
            }

            // there shouldn't be any instances removed as well, but again for paranoia reason:
            Collection<InstanceDescription> removed = instanceDiff.removed().get();
            if (!removed.isEmpty()) {
                sb.append("instances were removed:");
                for (InstanceDescription instance : added) {
                    sb.append(" ");
                    sb.append(instance.getSlingId());
                }
                sb.append(".");
            }

            Set<InstanceDescription> newInstances = event.getNewView()
                    .getInstances();
            for (Iterator<InstanceDescription> it = newInstances.iterator(); it
                    .hasNext();) {
                final InstanceDescription newInstanceDescription = it.next();
                InstanceDescription oldInstanceDescription = findInstance(
                        event.getOldView(), newInstanceDescription.getSlingId());
                if (oldInstanceDescription == null) {
                    logger.error("handleTopologyEvent: got a property changed but did not find instance "
                            + newInstanceDescription
                            + " in oldview.. event="
                            + event);
                    sb.append("did not find instance in old view: " + newInstanceDescription.getSlingId() + ".");
                    continue;
                }

                Map<String, String> oldProps = oldInstanceDescription
                        .getProperties();
                Map<String, String> newProps = newInstanceDescription
                        .getProperties();
                StringBuilder diff = diff(oldProps, newProps);
                if (diff.length() > 0) {
                    if (sb.length() != 0) {
                        sb.append(", ");
                    }
                    sb.append("on instance "
                            + newInstanceDescription.getSlingId() + (newInstanceDescription.isLeader() ? " [isLeader]" : "")
                            + ": " + diff + ". ");
                }
            }

            addEventLog(event.getType(), "details: "+sb.toString());
        } else if (event.getType() == Type.TOPOLOGY_INIT) {
            this.currentView = event.getNewView();
            StringBuilder details = new StringBuilder();
            for (Iterator<InstanceDescription> it = event.getNewView()
                    .getInstances().iterator(); it.hasNext();) {
                InstanceDescription newInstance = it.next();
                if (details.length() != 0) {
                    details.append(", ");
                }
                details.append(newInstance.getSlingId());
                if (newInstance.isLeader()) {
                    details.append(" [isLeader]");
                }
            }
            addEventLog(event.getType(),
                    "view: " + shortViewInfo(event.getNewView()) + ". "
                            + details);
        } else if (event.getType() == Type.TOPOLOGY_CHANGING) {
            this.currentView = event.getOldView();
            addEventLog(event.getType(),
                    "old view: " + shortViewInfo(event.getOldView()));
        } else {
            this.currentView = event.getNewView();
            if (event.getOldView() == null) {
                addEventLog(event.getType(),
                        "new view: " + shortViewInfo(event.getNewView()));
            } else {
                StringBuilder details = new StringBuilder();
                for (Iterator<InstanceDescription> it = event.getNewView()
                        .getInstances().iterator(); it.hasNext();) {
                    InstanceDescription newInstance = it.next();
                    if (findInstance(event.getOldView(),
                            newInstance.getSlingId()) == null) {
                        if (details.length() != 0) {
                            details.append(", ");
                        }
                        details.append(newInstance.getSlingId() + " joined");
                    }
                }
                for (Iterator<InstanceDescription> it = event.getOldView()
                        .getInstances().iterator(); it.hasNext();) {
                    InstanceDescription oldInstance = it.next();
                    if (findInstance(event.getNewView(),
                            oldInstance.getSlingId()) == null) {
                        if (details.length() != 0) {
                            details.append(", ");
                        }
                        details.append(oldInstance.getSlingId() + " left");
                    }
                }
                final InstanceDescription li = event.getNewView().getLocalInstance();
                if (li!=null) {
                    ClusterView clusterView = li.getClusterView();
                    if (clusterView!=null) {
                        final InstanceDescription leader = clusterView.getLeader();
                        if (leader!=null) {
                            if (details.length() !=0) {
                                details.append(", ");
                            }
                            details.append("[isLeader: "+leader.getSlingId()+"]");
                        }
                    }
                }

                addEventLog(
                        event.getType(),
                        "old view: " + shortViewInfo(event.getOldView())
                                + ", new view: "
                                + shortViewInfo(event.getNewView()) + ". "
                                + details);
            }
        }
        updateDiscoveryLiteHistory();
    }