StateMachineExecutionState.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / WF / Activities / StateMachineExecutionState.cs / 1305376 / StateMachineExecutionState.cs
                        
                        
                            #region Using directives 

using System;
using System.Collections;
using System.Collections.Generic; 
using System.Collections.Specialized;
using System.Reflection; 
using System.Diagnostics; 
using System.Runtime.Remoting.Messaging;
using System.Workflow.ComponentModel; 
using System.Workflow.ComponentModel.Design;
using System.Workflow.Runtime;
using System.Workflow.Runtime.Hosting;
 
#endregion Using directives
 
namespace System.Workflow.Activities 
{
    [Serializable] 
    internal class StateMachineExecutionState
    {
        #region Member Variables
 
        internal const string StateMachineExecutionStateKey = "StateMachineExecutionState";
        private StateMachineSubscriptionManager _subscriptionManager; 
        private Queue _actions; 
        private string _currentStateName;
        private string _previousStateName; 
        private string _nextStateName;
        private bool _completed = false;
        private bool _queueLocked = false;
        private bool _schedulerBusy = false; 

        #endregion Member Variables 
 
        #region Properties
 
        internal StateMachineSubscriptionManager SubscriptionManager
        {
            get
            { 
                return _subscriptionManager;
            } 
        } 

        private Queue Actions 
        {
            get
            {
                if (_actions == null) 
                    _actions = new Queue();
                return _actions; 
            } 
        }
 
        internal bool SchedulerBusy
        {
            get
            { 
                return _schedulerBusy;
            } 
            set 
            {
                _schedulerBusy = value; 
            }
        }

        internal string CurrentStateName 
        {
            get 
            { 
                return _currentStateName;
            } 
            set
            {
                _currentStateName = value;
            } 
        }
 
        internal string PreviousStateName 
        {
            get 
            {
                return _previousStateName;
            }
            set 
            {
                _previousStateName = value; 
            } 
        }
 
        internal string NextStateName
        {
            get
            { 
                return _nextStateName;
            } 
            set 
            {
                _nextStateName = value; 
            }
        }

        internal bool Completed 
        {
            get 
            { 
                return _completed;
            } 
            set
            {
                _completed = value;
            } 
        }
 
        internal bool HasEnqueuedActions 
        {
            get 
            {
                return this.Actions.Count > 0;
            }
        } 

        #endregion Properties 
 
        #region Constructors
 
        internal StateMachineExecutionState(Guid instanceId)
        {
            _subscriptionManager = new StateMachineSubscriptionManager(this, instanceId);
        } 

        #endregion 
 
        internal void LockQueue()
        { 
            _queueLocked = true;
        }

        internal void EnqueueAction(StateMachineAction action) 
        {
            Debug.Assert(!this._queueLocked); 
            this.Actions.Enqueue(action); 
        }
 
        internal StateMachineAction DequeueAction()
        {
            StateMachineAction action = this.Actions.Dequeue();
            if (this.Actions.Count == 0) 
                _queueLocked = false;
            return action; 
        } 

        internal void ProcessActions(ActivityExecutionContext context) 
        {
            if (context == null)
                throw new ArgumentNullException("context");
 
            if (this.SchedulerBusy)
                return; 
 
            StateActivity state = (StateActivity)context.Activity;
 
            if (this.Actions.Count == 0)
            {
                this.SubscriptionManager.ProcessQueue(context);
                return; 
            }
 
            StateMachineAction action = this.Actions.Peek(); 
            while (action.StateName.Equals(state.QualifiedName))
            { 
                action = DequeueAction();
                action.Execute(context);

                // If the previous action just 
                // requested something to the runtime
                // scheduler, then we quit, since 
                // the scheduler takes precedence. 
                // we'll pick up the processing of actions
                // after the scheduler return the control to us. 
                if (this.SchedulerBusy)
                    return;

                if (this.Actions.Count == 0) 
                    break;
 
                action = this.Actions.Peek(); 
            }
 
            if (this.Actions.Count > 0)
            {
                StateActivity rootState = StateMachineHelpers.GetRootState(state);
                StateActivity nextActionState = StateMachineHelpers.FindDynamicStateByName(rootState, action.StateName); 
                if (nextActionState == null)
                    throw new InvalidOperationException(SR.GetInvalidStateMachineAction(action.StateName)); 
 
                nextActionState.RaiseProcessActionEvent(context);
            } 
            else
            {
                this.SubscriptionManager.ProcessQueue(context);
            } 
        }
 
 
        internal void ProcessTransitionRequest(ActivityExecutionContext context)
        { 
            if (String.IsNullOrEmpty(this.NextStateName))
                return;

            StateActivity currentState = StateMachineHelpers.GetCurrentState(context); 
            CalculateStateTransition(currentState, this.NextStateName);
            LockQueue(); 
            this.NextStateName = null; 
        }
 
        internal void CalculateStateTransition(StateActivity currentState, string targetStateName)
        {
            if (currentState == null)
                throw new ArgumentNullException("currentState"); 
            if (String.IsNullOrEmpty(targetStateName))
                throw new ArgumentNullException("targetStateName"); 
 
            while (currentState != null && (currentState.QualifiedName.Equals(targetStateName) || !StateMachineHelpers.ContainsState(currentState, targetStateName)))
            { 
                CloseStateAction action = new CloseStateAction(currentState.QualifiedName);
                this.Actions.Enqueue(action);
                currentState = currentState.Parent as StateActivity;
            } 
            if (currentState == null)
                throw new InvalidOperationException(SR.GetUnableToTransitionToState(targetStateName)); 
 
            while (!currentState.QualifiedName.Equals(targetStateName))
            { 
                foreach (Activity childActivity in currentState.EnabledActivities)
                {
                    StateActivity childState = childActivity as StateActivity;
                    if (childState != null) 
                    {
                        // 
                        if (StateMachineHelpers.ContainsState(childState, targetStateName)) 
                        {
                            ExecuteChildStateAction action = new ExecuteChildStateAction(currentState.QualifiedName, childState.QualifiedName); 
                            this.Actions.Enqueue(action);
                            currentState = childState;
                            break;
                        } 
                    }
                } 
            } 
            if (!StateMachineHelpers.IsLeafState(currentState))
                throw new InvalidOperationException(SR.GetInvalidStateTransitionPath()); 
        }

        #region Static Methods
 
        internal static StateMachineExecutionState Get(StateActivity state)
        { 
            Debug.Assert(StateMachineHelpers.IsRootState(state)); 
            StateMachineExecutionState executionState = (StateMachineExecutionState)state.GetValue(StateActivity.StateMachineExecutionStateProperty);
            Debug.Assert(executionState != null); 
            return executionState;
        }

        #endregion 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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StateMachineExecutionState.cs source code in C# .NET

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