private void doUpdate()

in common/src/main/java/org/mvndaemon/mvnd/common/DaemonRegistry.java [165:252]
84 lines of code
15 McCabe index (conditional complexity)

    private void doUpdate(Runnable updater) {
        if (!Files.isReadable(registryFile)) {
            throw new DaemonException("Registry became unaccessible");
        }

        synchronized (lck) {
            try (FileLock l = tryLock()) {
                channel.position(0);
                DataInputStream is = new DataInputStream(new BufferedInputStream(Channels.newInputStream(channel)));
                infosMap.clear();
                int nb = is.available() < 4 ? 0 : is.readInt();
                for (int i = 0; i < nb; i++) {
                    String daemonId = is.readUTF();
                    String javaHome = is.readUTF();
                    String mavenHome = is.readUTF();
                    int pid = is.readInt();
                    String address = is.readUTF();

                    byte[] token = new byte[DaemonInfo.TOKEN_SIZE];
                    is.read(token);

                    String locale = is.readUTF();
                    List<String> opts = new ArrayList<>();
                    int nbOpts = is.readInt();
                    for (int j = 0; j < nbOpts; j++) {
                        opts.add(is.readUTF());
                    }
                    DaemonState state = DaemonState.values()[is.readByte()];
                    long lastIdle = is.readLong();
                    long lastBusy = is.readLong();
                    DaemonInfo di = new DaemonInfo(
                            daemonId, javaHome, mavenHome, pid, address, token, locale, opts, state, lastIdle,
                            lastBusy);
                    infosMap.putIfAbsent(di.getId(), di);
                }
                stopEvents.clear();
                nb = is.available() < 4 ? 0 : is.readInt();
                for (int i = 0; i < nb; i++) {
                    String daemonId = is.readUTF();
                    long date = is.readLong();
                    int ord = is.readByte();
                    DaemonExpirationStatus des = ord >= 0 ? DaemonExpirationStatus.values()[ord] : null;
                    String reason = is.readUTF();
                    DaemonStopEvent se = new DaemonStopEvent(daemonId, date, des, reason);
                    stopEvents.add(se);
                }

                if (updater != null) {
                    updater.run();
                    channel.truncate(0);
                    DataOutputStream os =
                            new DataOutputStream(new BufferedOutputStream(Channels.newOutputStream(channel)));
                    os.writeInt(infosMap.size());
                    for (DaemonInfo di : infosMap.values()) {
                        String id = di.getId();
                        os.writeUTF(id);
                        os.writeUTF(di.getJavaHome());
                        os.writeUTF(di.getMvndHome());
                        os.writeInt(di.getPid());
                        os.writeUTF(di.getAddress());
                        os.write(di.getToken());
                        os.writeUTF(di.getLocale());
                        os.writeInt(di.getOptions().size());
                        for (String opt : di.getOptions()) {
                            os.writeUTF(opt);
                        }
                        os.writeByte((byte) di.getState().ordinal());
                        os.writeLong(di.getLastIdle());
                        os.writeLong(di.getLastBusy());
                    }
                    os.writeInt(stopEvents.size());
                    for (DaemonStopEvent dse : stopEvents) {
                        os.writeUTF(dse.getDaemonId());
                        os.writeLong(dse.getTimestamp());
                        os.writeByte((byte)
                                (dse.getStatus() == null ? -1 : dse.getStatus().ordinal()));
                        os.writeUTF(dse.getReason());
                    }
                    os.flush();
                }
            } catch (DaemonException e) {
                throw e;
            } catch (Exception e) {
                LOGGER.warn("Invalid daemon registry info at [{}], trying to recover.", registryFile, e);
                this.reset();
            }
        }
    }