A .NET State Machine Toolkit - Part I

/*
 * Created by: Leslie Sanford
 * 
 * Contact: jabberdabber@hotmail.com
 * 
 * Last modified: 11/05/2005
 */

using System;
using System.CodeDom;
using System.Collections;

namespace StateMachineToolkit
{
	/// <summary>
	/// Builds the methods that make up the state machine.
	/// </summary>
	internal class MethodBuilder
	{
        #region MethodBuilder Members

        #region Fields

        private string stateMachineName = string.Empty;

        private string initialState = string.Empty;

        // The state machine's states.
        private ICollection states;

        // The state machine's guards.
        private ICollection guards;

        // The state machine's actions.
        private ICollection actions;

        // Builds initializing methods.
        private InitializeMethodBuilder initializeMethodBuilder;        

        // The collection of built methods.
        private ArrayList methods = new ArrayList();

        #endregion

        #region Construction

        /// <summary>
        /// Initializes a new instance of the MethodBuilder class with all
        /// of the tables necessary to build the state machine methods.
        /// </summary>
        /// <param name="states">
        /// The state machine's states.
        /// </param>
        /// <param name="evets">
        /// The state machine's events.
        /// </param>
        /// <param name="guards">
        /// The state machine's guards.
        /// </param>
        /// <param name="actions">
        /// The state machine's actions.
        /// </param>
        /// <param name="stateTransitions">
        /// The state transitions.
        /// </param>
        /// <param name="stateRelationships">
        /// The substate/superstate relationships.
        /// </param>
        /// <param name="stateHistoryTypes">
        /// The state history types.
        /// </param>
        /// <param name="stateInitialStates">
        /// The states' initial states.
        /// </param>
		public MethodBuilder(ICollection states, ICollection events, 
            ICollection guards, ICollection actions, IDictionary stateTransitions,
            IDictionary stateRelationships, IDictionary stateHistoryTypes,
            IDictionary stateInitialStates)
		{
            this.states = states;
            this.guards = guards;
            this.actions = actions;
            
            initializeMethodBuilder = new InitializeMethodBuilder(states, events, 
                guards, actions, stateTransitions, stateRelationships, 
                stateHistoryTypes, stateInitialStates);
		}

        #endregion

        #region Methods

        /// <summary>
        /// Builds the methods for the state machine.
        /// </summary>
        public void Build()
        {
            methods = new ArrayList();

            // 
            // Builds initializing methods.
            //
           
            BuildInitializeMethod();
            initializeMethodBuilder.StateMachineName = StateMachineName;
            initializeMethodBuilder.Build();
            methods.AddRange(initializeMethodBuilder.Result);

            //
            // Build entry and exit actions.
            //

            BuildMethods(states, "Entry", MemberAttributes.Family, null, 
                typeof(void));
            BuildMethods(states, "Exit", MemberAttributes.Family, null, 
                typeof(void));

            CodeParameterDeclarationExpression args = 
                new CodeParameterDeclarationExpression(typeof(object[]), "args");

            // Build guard methods.
            BuildMethods(guards, string.Empty, 
                MemberAttributes.Family | MemberAttributes.Abstract, args, 
                typeof(bool));

            // Build action methods.
            BuildMethods(actions, string.Empty,
                MemberAttributes.Family | MemberAttributes.Abstract, args, 
                typeof(void));            
        }

        // Builds methods.
        private void BuildMethods(ICollection col, string methodPrefix, 
            MemberAttributes attributes, 
            CodeParameterDeclarationExpression args, Type returnType)
        {
            CodeMemberMethod method;

            foreach(string name in col)
            {
                method = new CodeMemberMethod();
                method.Name = methodPrefix + name;
                method.Attributes = attributes;
                method.ReturnType = new CodeTypeReference(returnType);

                if(args != null)
                {
                    method.Parameters.Add(args);
                }

                methods.Add(method);
            }
        }

        // Builds the initialize method.
        private void BuildInitializeMethod()
        {
            CodeThisReferenceExpression thisReference = 
                new CodeThisReferenceExpression();
            CodeMemberMethod initializeMethod = new CodeMemberMethod();

            initializeMethod.Name = "Initialize";
            initializeMethod.Attributes = MemberAttributes.Private;

            CodeMethodInvokeExpression methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeStates";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeGuards";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeActions";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeTransitions";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeRelationships";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeHistoryTypes";

            initializeMethod.Statements.Add(methodInvoke);

            methodInvoke = new CodeMethodInvokeExpression();

            methodInvoke.Method.TargetObject = thisReference;
            methodInvoke.Method.MethodName = "InitializeInitialStates";

            initializeMethod.Statements.Add(methodInvoke);

            CodeExpression[] parameters = 
                {
                    new CodeFieldReferenceExpression(thisReference,
                    "state" + InitialState) 
                };

            CodeMethodInvokeExpression initializeInvoke = 
                new CodeMethodInvokeExpression(thisReference,
                "Initialize", parameters);

            initializeMethod.Statements.Add(initializeInvoke);

            methods.Add(initializeMethod);
        }

        #endregion

        #region Properties

        /// <summary>
        /// Gets the collection of built methods.
        /// </summary>
        public ICollection Result
        {
            get
            {
                return methods;
            }
        }

        public string StateMachineName
        {
            get
            {
                return stateMachineName;
            }
            set
            {
                stateMachineName = value;
            }
        }

        /// <summary>
        /// Gets or sets the state machine's initial state.
        /// </summary>
        public string InitialState
        {
            get
            {
                return initialState;
            }
            set
            {
                initialState = value;
            }
        }

        #endregion

        #endregion
	}
}