StateMachine.java

package com.bell.arc.rerateorchestrator.service;

import com.bell.arc.rerateorchestrator.model.dto.request.RerateUsageRequestWrapper;
import com.bell.arc.rerateorchestrator.model.dto.request.StateHistory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class StateMachine {
    static RerateUsageRequestWrapper wrapper = new RerateUsageRequestWrapper();
    static {
        wrapper.setStateHistory(new StateHistory());
    }
    
    public State getStateHandler(String state) {
        return null; // use the getBean approach or something
    }

    public void execute(State s) {
        String result = s.doWork(wrapper);
        String nextState = s.nextState(result);

        if (wrapper.getStateHistory().getStateList().size() > 100 /* TODO: This could be smarter and take account of last update timestamp */) {
            throw new RuntimeException("infinite loop");
        }
        
        if (s.saveToAudit()) {
            // save to audit DB
        }
        
        if (s.saveToLocal()) {
            // save to local DB
        }
        
        if (s.saveToRedis()) {
            // save to Redis
        }
        
        execute(getStateHandler(nextState));
    }

    abstract static class State {
        private static final Logger LOG = LoggerFactory.getLogger(State.class);

        public abstract boolean isReady(RerateUsageRequestWrapper w);
        public abstract String doWork(RerateUsageRequestWrapper w);
        public abstract String nextState(String result);
        public abstract String getName();

        public abstract boolean saveToAudit();
        public abstract boolean saveToRedis();
        public abstract boolean saveToLocal();

        public static State create(String name, String result, String nextState, boolean a, boolean r, boolean l) {
            return new State() {
                @Override
                public String doWork(RerateUsageRequestWrapper w) {
                    LOG.info("doing work");
                    return result;
                }

                @Override
                public String nextState(String result) {
                    return nextState;
                }

                @Override
                public String getName() {
                    return name;
                }

                @Override
                public boolean saveToAudit() {
                    return a;
                }

                @Override
                public boolean saveToRedis() {
                    return r;
                }

                @Override
                public boolean saveToLocal() {
                    return l;
                }
            }
        }
    }
}