public RemoteInvocation createRemoteInvocation()

in support/spring/src/main/java/org/apache/shiro/spring/remoting/SecureRemoteInvocationFactory.java [79:143]
50 lines of code
15 McCabe index (conditional complexity)

    public RemoteInvocation createRemoteInvocation(MethodInvocation mi) {

        Serializable sessionId = null;
        String host = null;
        boolean sessionManagerMethodInvocation = false;

        //If the calling MI is for a remoting SessionManager delegate, we need to acquire the session ID from the method
        //argument and NOT interact with SecurityUtils/subject.getSession to avoid a stack overflow
        Class miDeclaringClass = mi.getMethod().getDeclaringClass();
        if (SessionManager.class.equals(miDeclaringClass) || NativeSessionManager.class.equals(miDeclaringClass)) {
            sessionManagerMethodInvocation = true;
            //for SessionManager calls, all method calls except the 'start' methods require a SessionKey
            // as the first argument, so just get it from there:
            if (!mi.getMethod().getName().equals("start")) {
                SessionKey key = (SessionKey) mi.getArguments()[0];
                sessionId = key.getSessionId();
            }
        }

        //tried the delegate. Use the injected session id if given
        if (sessionId == null) {
            sessionId = this.sessionId;
        }

        // If sessionId is null, only then try the Subject:
        if (sessionId == null) {
            try {
                // HACK Check if can get the securityManager - this'll cause an exception if it's not set
                SecurityUtils.getSecurityManager();
                if (!sessionManagerMethodInvocation) {
                    Subject subject = SecurityUtils.getSubject();
                    Session session = subject.getSession(false);
                    if (session != null) {
                        sessionId = session.getId();
                        host = session.getHost();
                    }
                }
            } catch (Exception e) {
                LOGGER.trace("No security manager set. Trying next to get session id from system property");
            }
        }
        //No call to the sessionManager, and the Subject doesn't have a session.  Try a system property
        //as a last result:
        if (sessionId == null) {
            if (LOGGER.isTraceEnabled()) {
                LOGGER.trace("No Session found for the currently executing subject via subject.getSession(false).  "
                        + "Attempting to revert back to the 'shiro.session.id' system property...");
            }
            sessionId = System.getProperty(SESSION_ID_SYSTEM_PROPERTY_NAME);
            if (sessionId == null && LOGGER.isTraceEnabled()) {
                LOGGER.trace("No 'shiro.session.id' system property found.  Heuristics have been exhausted; "
                        + "RemoteInvocation will not contain a sessionId.");
            }
        }

        RemoteInvocation ri = new RemoteInvocation(mi);
        if (sessionId != null) {
            ri.addAttribute(SESSION_ID_KEY, sessionId);
        }
        if (host != null) {
            ri.addAttribute(HOST_KEY, host);
        }

        return ri;
    }