protected int run()

in core/src/main/java/hudson/cli/BuildCommand.java [102:221]
99 lines of code
31 McCabe index (conditional complexity)

    protected int run() throws Exception {
        job.checkPermission(Item.BUILD);

        ParametersAction a = null;
        if (!parameters.isEmpty()) {
            ParametersDefinitionProperty pdp = job.getProperty(ParametersDefinitionProperty.class);
            if (pdp==null)
                throw new IllegalStateException(job.getFullDisplayName()+" is not parameterized but the -p option was specified.");

            //TODO: switch to type annotations after the migration to Java 1.8
            List<ParameterValue> values = new ArrayList<>();

            for (Entry<String, String> e : parameters.entrySet()) {
                String name = e.getKey();
                ParameterDefinition pd = pdp.getParameterDefinition(name);
                if (pd==null) {
                    String nearest = EditDistance.findNearest(name, pdp.getParameterDefinitionNames());
                    throw new CmdLineException(null, nearest == null ?
                            String.format("'%s' is not a valid parameter.", name) :
                            String.format("'%s' is not a valid parameter. Did you mean %s?", name, nearest));
                }
                ParameterValue val = pd.createValue(this, Util.fixNull(e.getValue()));
                if (val == null) {
                    throw new CmdLineException(null, String.format("Cannot resolve the value for the parameter '%s'.",name));
                }
                values.add(val);
            }

            // handle missing parameters by adding as default values ISSUE JENKINS-7162
            for(ParameterDefinition pd :  pdp.getParameterDefinitions()) {
                if (parameters.containsKey(pd.getName()))
                    continue;

                // not passed in use default
                ParameterValue defaultValue = pd.getDefaultParameterValue();
                if (defaultValue == null) {
                    throw new CmdLineException(null, String.format("No default value for the parameter '%s'.",pd.getName()));
                }
                values.add(defaultValue);
            }

            a = new ParametersAction(values);
        }

        if (checkSCM) {
            SCMTriggerItem item = SCMTriggerItem.SCMTriggerItems.asSCMTriggerItem(job);
            if (item == null)
                throw new AbortException(job.getFullDisplayName()+" has no SCM trigger, but checkSCM was specified");
            // preemptively check for a polling veto
            if (SCMDecisionHandler.firstShouldPollVeto(job) != null) {
                return 0;
            }
            if (!item.poll(new StreamTaskListener(stdout, getClientCharset())).hasChanges())
                return 0;
        }

        if (!job.isBuildable()) {
            String msg = Messages.BuildCommand_CLICause_CannotBuildUnknownReasons(job.getFullDisplayName());
            if (job instanceof ParameterizedJobMixIn.ParameterizedJob && ((ParameterizedJobMixIn.ParameterizedJob) job).isDisabled()) {
                msg = Messages.BuildCommand_CLICause_CannotBuildDisabled(job.getFullDisplayName());
            } else if (job.isHoldOffBuildUntilSave()){
                msg = Messages.BuildCommand_CLICause_CannotBuildConfigNotSaved(job.getFullDisplayName());
            }
            throw new IllegalStateException(msg);
        }

        Queue.Item item = ParameterizedJobMixIn.scheduleBuild2(job, 0, new CauseAction(new CLICause(Jenkins.getAuthentication().getName())), a);
        QueueTaskFuture<? extends Run<?,?>> f = item != null ? (QueueTaskFuture)item.getFuture() : null;
        
        if (wait || sync || follow) {
            if (f == null) {
                throw new IllegalStateException(BUILD_SCHEDULING_REFUSED);
            }
            Run<?,?> b = f.waitForStart();    // wait for the start
            stdout.println("Started "+b.getFullDisplayName());
            stdout.flush();

            if (sync || follow) {
                try {
                    if (consoleOutput) {
                        // read output in a retry loop, by default try only once
                        // writeWholeLogTo may fail with FileNotFound
                        // exception on a slow/busy machine, if it takes
                        // longish to create the log file
                        int retryInterval = 100;
                        for (int i=0;i<=retryCnt;) {
                            try {
                                b.writeWholeLogTo(stdout);
                                break;
                            }
                            catch (FileNotFoundException | NoSuchFileException e) {
                                if ( i == retryCnt ) {
                                    Exception myException = new AbortException();
                                    myException.initCause(e);
                                    throw myException;
                                }
                                i++;
                                Thread.sleep(retryInterval);
                            }
                        }
                    }
                    f.get();    // wait for the completion
                    stdout.println("Completed "+b.getFullDisplayName()+" : "+b.getResult());
                    return b.getResult().ordinal;
                } catch (InterruptedException e) {
                    if (follow) {
                        return 125;
                    } else {
                        // if the CLI is aborted, try to abort the build as well
                        f.cancel(true);
                        Exception myException = new AbortException();
                        myException.initCause(e);
                        throw myException;
                    }
                }
            }
        }

        return 0;
    }