/// <summary>
/// Returns total number of times current promotion has been used by current customer. The results are cached.
/// </summary>
/// <value>The customer used count.</value>
public int GetCustomerUsageCount(Guid customerId)
{
DataTable usage = null;
// Load customer specific
string cacheKey = MarketingCache.CreateCacheKey("MarketingHelper-customer", customerId.ToString());
object cachedObject = MarketingCache.Get(cacheKey);
if (cachedObject != null)
{
usage = (DataTable)cachedObject;
}
else
{
usage = PromotionManager.GetPromotionUsageStatistics(customerId);
MarketingCache.Insert(cacheKey, usage, MarketingConfiguration.Instance.CacheConfig.PromotionCollectionTimeout);
}
System.Data.DataRow[] rows = usage.Select(String.Format("PromotionId = {0}", DataRow.PromotionId));
if (rows != null && rows.Length > 0)
{
return((int)rows[0]["TotalUsed"]);
}
return(0);
}
/// <summary>
/// Evals the specified expression against the context passed in the dictionary.
/// </summary>
/// <param name="key">The key. Must be a unique key identifying the current expression. It might be used for caching purpose by the engine.</param>
/// <param name="expr">The expr.</param>
/// <param name="context">The context, which consists of object that will be accessible during expression evaluation.</param>
/// <returns></returns>
public ValidationResult Eval(string key, string expr, IDictionary <string, object> context)
{
string cacheKey = MarketingCache.CreateCacheKey("Expression-engine", key);
// check cache first
object cachedObject = MarketingCache.Get(cacheKey);
RuleEngine ruleEngine = null;
// Return true if empty
if (String.IsNullOrEmpty(expr))
{
return(new ValidationResult(true, String.Empty));
}
if (cachedObject != null)
{
ruleEngine = (RuleEngine)cachedObject;
}
else
{
lock (MarketingCache.GetLock(cacheKey))
{
ruleEngine = (RuleEngine)MarketingCache.Get(cacheKey);
if (ruleEngine == null)
{
// Try to deserialize rules
RuleSet ruleSet = DeserializeRuleSet(expr);
// If empty, return false
if (ruleSet == null)
{
return(new ValidationResult(false, String.Empty));
}
ruleEngine = new RuleEngine(ruleSet, new RuleValidation(typeof(RulesContext), null));
// Save in cache
MarketingCache.Insert(cacheKey, ruleEngine, MarketingConfiguration.Instance.CacheConfig.ExpressionCollectionTimeout);
}
}
}
// Initialize context object
RulesContext rulesContext = new RulesContext(context);
if (ruleEngine == null)
{
throw new NullReferenceException("RuleEngine object can not be null");
}
try
{
ruleEngine.Execute(rulesContext);
}
catch (RuleSetValidationException ex)
{
string errorMessage = String.Empty;
foreach (ValidationError error in ex.Errors)
{
errorMessage += "\n\r" + error.ToString();
}
throw new ApplicationException(errorMessage, ex);
}
catch (RuleEvaluationException ex)
{
//If runtime error then skip promotion
System.Diagnostics.Trace.WriteLine(String.Format("evaluation error {0} ... skip promotion", ex.Message));
}
catch (TargetInvocationException ex)
{
//If runtime error then skip promotion
System.Diagnostics.Trace.WriteLine(String.Format("evaluation error {0} ... skip promotion", ex.Message));
}
// Return result
return(rulesContext.ValidationResult);
}