/// <summary>
/// Second part of the rule declaration; specifies the function that will compute the value of the target property
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="valueComputer"></param>
/// <returns></returns>
public static FluentToken <TParent, TTargetProperty> With <TParent, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, Expression <Func <TParent, TTargetProperty> > valueComputer)
{
token.ValueComputer = valueComputer.Compile();
return(token);
}
/// <summary>
/// Specifies an optional applicability condition as a predicate; if false the rule will not be triggered
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="ifPredicate"></param>
/// <returns></returns>
public static FluentToken <TParent, TTargetProperty> If <TParent, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, Predicate <TParent> ifPredicate)
{
token.IfPredicate = ifPredicate;
return(token);
}
/// <summary>
/// Specifies an extra trigger property. Multiple statements may be chained
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TProperty"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="propertySelector"></param>
/// <returns></returns>
public static FluentToken <TParent, TTargetProperty> Or <TParent, TProperty, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, Expression <Func <TParent, TProperty> > propertySelector)
{
token.PropertyNames.Add(ExpressionTreeHelper.PropertyName(propertySelector));
return(token);
}
/// <summary>
/// Second part of the rule declaration; specifies the function that will compute the value of the target property
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="valueComputer"></param>
/// <param name="manualExplain">optionally provide a human readable description</param>
/// <returns></returns>
public static FluentToken <TParent, TTargetProperty> With <TParent, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, Expression <Func <TParent, TTargetProperty> > valueComputer, string manualExplain = null)
{
token.ValueComputerExplained = manualExplain ?? valueComputer.TryExplain();
token.ValueComputer = valueComputer.Compile();
return(token);
}
/// <summary>
/// Specifies an optional applicability condition as a predicate; if false the rule will not be triggered
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="ifPredicate"></param>
/// <param name="manualExplain">optionally provide a human readable description</param>
/// <returns></returns>
public static FluentToken <TParent, TTargetProperty> If <TParent, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, Expression <Func <TParent, bool> > ifPredicate, string manualExplain = null)
{
token.IfPredicate = ifPredicate.Compile();
token.IfExplained = manualExplain ?? ifPredicate.TryExplain();
return(token);
}
/// <summary>
/// Specifies the first trigger property
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
/// <param name="propertySelectors"></param>
/// <returns></returns>
public static void OnChanged <TParent, TTargetProperty>(
this FluentToken <TParent, TTargetProperty> token, params Expression <Func <TParent, object> >[] propertySelectors)
{
foreach (var propertySelector in propertySelectors)
{
token.PropertyNames.Add(ExpressionTreeHelper.PropertyName(propertySelector));
}
var propertyName = ExpressionTreeHelper.PropertyName(token.TargetPropertySelector);
bool Updater(TParent parent)
{
if (token.IfPredicate != null)
{
if (!token.IfPredicate(parent))
{
return(false);
}
}
var newValue = token.ValueComputer(parent);
var oldValue = RuntimeCompiler <TParent, TTargetProperty> .Getter(token.TargetPropertySelector)(parent);
if (Equals(oldValue, newValue))
{
return(false);
}
RuntimeCompiler <TParent, TTargetProperty> .SetterFromGetter(token.TargetPropertySelector)(parent,
newValue);
return(true);
}
var rule = new Rule <TParent>
{
TriggerProperties = token.PropertyNames,
Updater = Updater,
TargetPropertyName = propertyName,
IfExplained = token.IfExplained,
ValueComputerExplained = token.ValueComputerExplained
};
token.MappingRulesContainer.Rules.Add(rule);
foreach (var name in token.PropertyNames)
{
if (!token.MappingRulesContainer.RulesByTrigger.TryGetValue(name, out var rules))
{
rules = new List <Rule <TParent> >();
token.MappingRulesContainer.RulesByTrigger.Add(name, rules);
}
rules.Add(rule);
}
}
/// <summary>
/// Always the last NON OPTIONAL statement in a rule declaration
/// Internally produces an instance of <see cref="Rule{TParent}" /> and adds it into the rules engine
/// </summary>
/// <typeparam name="TParent"></typeparam>
/// <typeparam name="TTargetProperty"></typeparam>
/// <param name="token"></param>
public static void EndRule <TParent, TTargetProperty>(this FluentToken <TParent, TTargetProperty> token)
{
if (token.MappingRulesContainer == null)
{
throw new NotSupportedException("Error in fluent syntax. Start with a Set() statement");
}
var propertyName = ExpressionTreeHelper.PropertyName(token.TargetPropertySelector);
bool Updater(TParent parent)
{
if (token.IfPredicate != null)
{
if (!token.IfPredicate(parent))
{
return(false);
}
}
var newValue = token.ValueComputer(parent);
var oldValue = RuntimeCompiler <TParent, TTargetProperty> .Getter(token.TargetPropertySelector)(parent);
if (Equals(oldValue, newValue))
{
return(false);
}
RuntimeCompiler <TParent, TTargetProperty> .SetterFromGetter(token.TargetPropertySelector)(parent,
newValue);
return(true);
}
var rule = new Rule <TParent>
{
TriggerProperties = token.PropertyNames,
Updater = Updater,
TargetPropertyName = propertyName
};
foreach (var name in token.PropertyNames)
{
if (!token.MappingRulesContainer.RulesByTrigger.TryGetValue(name, out var rules))
{
rules = new List <Rule <TParent> >();
token.MappingRulesContainer.RulesByTrigger.Add(name, rules);
}
rules.Add(rule);
}
}