validation rules across entities

Is it possible and if so how would I add validation rules that span across entities:

for example ie have a Product and it can have many child ProductAttributes - one attribute may be a startdate and another enddate - can I validate that the enddate is > startdate in my Product? (or maybe the Service??)

TIA

swin

There are currently a few ways you can do this.  The most instinctual way would be to create a validation rule in the Product entity that checks against' it's product types. But  are the product Attributes just an entity with Key Value pairs?  It sounds like it since your are saying it could or could not have those attributes, so it sounds to me like you would have a Key Value Pair. 

If so, then you could find those attributes:

        private bool ValidateAttributeDateRange(object target, Validation.ValidationRuleArgs e)
        {

	    //This will only get set if you return false, so you can define your error message early.
            e.Message = "Product Attributes End Date must be before Start Date";
            
            int start = this.ProductAttributeCollection.Find(ProductAttributeColumns.Key, "StartDate");
            int end = this.ProductAttributeCollection.Find(ProductAttributeColumns.Key, "EndDate");
            if (start < 0 || end < 0)  
                return false;
            
            DateTime paStart = this.ProductAttributeCollection[start].Value ?? DateTime.MinValue;
            DateTime paEnd = this.ProductAttributeCollection[end].Value ?? DateTime.MinValue;
            if (paStart > paEnd)
                return false;
            return true;
        }

I assume that for this to work though I will have had to DeepLoad my ProductAttributes first?  This is not generally a problem where I can control everything, but aren't there places in the depths of NetTiers where the an entity is checked to be valid but won't necessarily be DeepLoaded? i.e. on Update in an EntityDataSource? and so the validation will fail?

You are right in saying that I won't necesarily always have both "start" and "end" dates.  Unfortunately the nature of our (financial) Products is such that they have a wide variety of attributes and so restricting to a fixed column format is difficult as we'd be forever changing our structure.  So we decided to put the dynamic attributes into a child table but this poses it own problems as well!

swin

I'm facing an issue similar to the one swin describes. Let's say I have a Salary entity. When a Salary is added or updated, the standard validation rules are applied (no nulls, proper date format, etc) but there's a custom business rule I'd like to apply: the new or updating Salary can't have a StartDate that is between an existing Salary's StartDate and EndDate. To apply that rule I need to retrieve the other Salary entities and do some comparing. Here's how I've handled it (using the ServiceLayer):

I wrote a processor that compares the new or updating Salary to existing ones. I'm inserting the processor into the service pipeline in the SalaryService class like so:

 public override bool Insert(Salary entity)
        {
            ProcessorList.Add(new App_Code.Processors.NewSalaryAdjustmentProcessor(ref entity));
            Execute();
            return base.Insert(entity);
        }

Now, the problems. When the processor sees a violation of the rule, I'm not sure what to do. Since I'm not using the Entity ValidationRules, I can't copy a BrokenRulesList into the ProcessResult. As a result, I have no meaningful way let the user know that a rule was violated. I'm leery of adding a ValidationRuleHandler to the SalaryEntity that calls the SalaryService to retrieve a TList<Salary>...it seems wrong, but maybe I've smoked too much smack. I'm guessing I may be approaching this completely bass ackwards.

Is there an elegant/preferred solution?

Cheers,

Evan

 

I should have elaborated a little more on what I'm thinking about doing to make the Service/Processor route fit my needs:

*Manually create a BrokenRule and BrokenRuleList inside the processor when a custom business rule is broken and append the BrokenRuleList to the processor's  ProcessResult via the AddBrokenRulesList method

*Create a custom ProcessorResult  (that inherits IProcessorResult) that provides a way to add information about rule violations.

 Any thoughts?
 

Those are both fine ideas that could work so that you don't have to maintain the logic inside of the entity.  Personally, i like to inject my rules dependant on the processor, but, again, this requires you to expose a method that allows this.  Your way is non-intrusive, which is good.

Thanks for the reply, Robert. A quick followup question: I'm doing these inserts and updates from an EntityDataSource. I'm not really a huge fan of inserting custom processors inside the Update and Insert methods of the EntityService itself. Is my only other option to insert them in the GridView_Inserting or _Deleting events?

Cheers (and thanks!)

Evan 

Hi Evan,

 What did you do in the end regarding your processor and datasource/form/service?

Cheers

swin

Hi swin,

I'm sorry I neglected to make good on my promise to post my method. Deadlines are a killer :) Those deadlines also prevented me from implementing this *exactly* like I wanted to, but I had to settle for good enough.

The meat of this solution is in the EntityDataSourceEventAdapter:

using System;
using System.Collections.Generic;
using System.Text;


namespace SBRILD.Web.App_Code
{
    public class EntityDataSourceEventAdapter
    {
        public void RegisterDataSource<D, P>(D ds, P provider)
            where D : SBRILD.Web.Data.IDataSourceEvents, SBRILD.Web.Data.ILinkedDataSource
            where P : SBRILD.Services.IComponentService
        {
            MessageAdapter<D, P> ma = new MessageAdapter<D, P>();
            ma.RegisterIndividualDataSource(ds, provider);
            ma.DataSourceMessageEvent += new MessageAdapter<D, P>.DataSourceMessageReport(DataSourceMessageReported);
        }

        void DataSourceMessageReported(Object sender, string message)
        {
            MessageReported(sender, message);
        }

        public delegate void MessageRaised(Object sender, String message);
        public event MessageRaised MessageReported;
    }

    class MessageAdapter<D, P>
        where D : SBRILD.Web.Data.IDataSourceEvents, SBRILD.Web.Data.ILinkedDataSource
        where P : SBRILD.Services.IComponentService
    {
        //Service provider
        private SBRILD.Services.IComponentService service;
        private String messages = String.Empty;

        /// <summary>
        /// Register a datasource's Inserted and Updated events
        /// </summary>
        /// <param name="ds"></param>
        /// <param name="provider"></param>
        public void RegisterIndividualDataSource(D ds, P provider)
        {
            //Register Inserted and AfterInserted event handles
            ds.Inserted += new System.Web.UI.WebControls.ObjectDataSourceStatusEventHandler(ds_Inserted);
            //ds.AfterInserted += new SBRILD.Web.Data.LinkedDataSourceEventHandler(ds_AfterInserted);
           
            //Register Updated and AfterUpdated event handlers
            ds.Updated += new System.Web.UI.WebControls.ObjectDataSourceStatusEventHandler(ds_Updated);
            //ds.AfterUpdated += new SBRILD.Web.Data.LinkedDataSourceEventHandler(ds_AfterUpdated);

            //Register service provider
            service = provider;
        }

        /// <summary>
        /// Occurs when a DataSource's Inserted event is fired
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void ds_Inserted(object sender, System.Web.UI.WebControls.ObjectDataSourceStatusEventArgs e)
        {
            //Iterate through each of the service's processors
            foreach (SBRILD.Services.ProcessorBase proc in service.ProcessorList)
            {
                //Get the result associated with this processor
                SBRILD.Services.IProcessorResult result = proc.ProcessResult;

                //Get each BrokenRulesList from the processor
                foreach (KeyValuePair<Type, SBRILD.Entities.Validation.BrokenRulesList> kvp in result.BrokenRulesLists)
                {
                    //Get each BrokenRule from the BrokenRulesList
                    foreach (SBRILD.Entities.Validation.BrokenRule br in kvp.Value)
                    {
                        //Report broken rule
                        //MessageEvent(br.Description.ToString());
                        messages += br.Description;
                    }
                }

                //Define an IWarningProcessorResult
                SBRILD.Services.App_Code.IWarningProcessorResult warningResult = proc.ProcessResult as SBRILD.Services.App_Code.IWarningProcessorResult;

                //If it exists
                if (warningResult != null)
                {
                    //Get each warning message in the list
                    foreach (String warning in warningResult.WarningList)
                    {
                        messages += warning;
                    }
                }

            }

            //Handle any EntityNotValidExceptions
            if (e.Exception != null && e.Exception.GetType() == typeof(SBRILD.Entities.EntityNotValidException))
            {
                e.ExceptionHandled = true;
            }

            if (messages != String.Empty)
            {
                DataSourceMessageEvent(sender, messages);
            }
        }

        /// <summary>
        /// Occurs when a DataSource's Updated event is fired
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void ds_Updated(object sender, System.Web.UI.WebControls.ObjectDataSourceStatusEventArgs e)
        {
            //Iterate through each of the service's processors
            foreach (SBRILD.Services.ProcessorBase proc in service.ProcessorList)
            {
                //Get the result associated with this processor
                SBRILD.Services.IProcessorResult result = proc.ProcessResult;

                //Get each BrokenRulesList from the processor
                foreach (KeyValuePair<Type, SBRILD.Entities.Validation.BrokenRulesList> kvp in result.BrokenRulesLists)
                {
                    //Get each BrokenRule from the BrokenRulesList
                    foreach (SBRILD.Entities.Validation.BrokenRule br in kvp.Value)
                    {
                        //Report broken rule
                        //MessageEvent(br.Description.ToString());
                        messages += br.Description;
                    }
                }

                //Define an IWarningProcessorResult
                SBRILD.Services.App_Code.IWarningProcessorResult warningResult = proc.ProcessResult as SBRILD.Services.App_Code.IWarningProcessorResult;

                //If it exists
                if (warningResult != null)
                {
                    //Get each warning message in the list
                    foreach (String warning in warningResult.WarningList)
                    {
                        messages += warning;
                    }
                }

            }

            //Handle any EntityNotValidExceptions
            if (e.Exception != null && e.Exception.GetType() == typeof(SBRILD.Entities.EntityNotValidException))
            {
                e.ExceptionHandled = true;
            }

            if (messages != String.Empty)
            {
                DataSourceMessageEvent(sender, messages);
            }
        }

        public delegate void DataSourceMessageReport(Object sender, String message);
        public event DataSourceMessageReport DataSourceMessageEvent;
    }
}

//END

I'm using the ServiceLayer model. Even more specifically, the processor results returned from the service's execution implement a custom interface (IWarningProcessorResult) in addition to extending nettier's GenericProcessorResult. The idea here is that I have a number of processors that modify entities that would otherwise be invalid. These modifications prevent some entities from being flagged as invalid (and thus providing information in the BrokenRulesList), but I still need to notify the user that the adjustments were made (an example here is a percentage entity that is increased by, say, 7%, and this increase makes the sum of some related entities = 103%...the processor would reduce the 7% to 4% so the total was 100%, and then inform the user of the automatic reduction) . That's where the IWarningProcessorResult came in:

    /// <summary>
    /// The interface that processors implement if they report warnings in addition to the
    /// BrokenRules reported by entity validation
    /// </summary>
    public interface IWarningProcessorResult
    {
        /// <summary>
        /// List of strings describing each warning
        /// </summary>
        List<String> WarningList { get;}
    }

//END 

The Inserted and Updated event handlers iterate through the BrokenRulesLists and WarningLists and fires an event reporting the messages. I've hooked up to that event in the asp page (also, here's where I register the DataSources):

    private void RegisterDataSourceEventHandlers()
    {
        //Create new EntityDataSourceEventAdapter
        SBRILD.Web.App_Code.EntityDataSourceEventAdapter edsa = new SBRILD.Web.App_Code.EntityDataSourceEventAdapter();

        //Register data sources
        edsa.RegisterDataSource(DefaultDistributionDataSource, DefaultDistributionDataSource.Provider as SBRILD.Services.IComponentService);
        edsa.RegisterDataSource(SalaryDataSource, SalaryDataSource.Provider as SBRILD.Services.IComponentService);
       
        //Register event handler will write messages to page that  that will
        edsa.MessageReported += new SBRILD.Web.App_Code.EntityDataSourceEventAdapter.MessageRaised(edsa_MessageReported);      
    }

    /// <summary>
    /// Handle messages sent from the EntityDataSourceEventAdapter
    /// </summary>
    /// <param name="message"></param>
    void edsa_MessageReported(Object sender, string message)
    {
        DataSourceEventsText = message;
    }
 

I wish I had time to make the implementation more generic, but then again, I wish I had more time for alot of things :) I'm absolutely positive there are better ways to accomplish this, but alas, I needed a concrete implementation and fast. Please do let me know if there's anything that doens't make sense or isn't helpful.

Cheers,

Evan

 

Hi Evan,

Will you be able to guide me how you implemented the IWarningProcessorResult.

I want to send the warning and not the Broken Rule. I am using your above said class. Just not able to fiqure out how I hook it in my processor class.

 Can you please show me some code where you implemented where you added the warning

thank you very much

Vijay

Hi Vijay,

Good question. What I did was create a custom ProcessorResult class that implements the NetTiers GenericProcessorResult class and the IWarningProcessorResult interface, like so:

using System;
using System.Collections.Generic;
using System.Text;

    /// <summary>
    /// A custom processor result
    /// </summary>
    public class CustomProcessorResult : Services.GenericProcessorResult, IWarningProcessorResult
    {
        private System.Collections.Generic.List<String> warningList;
       
        public List<String> WarningList
        {
            get
            {
                if (warningList == null)
                {
                    warningList = new System.Collections.Generic.List<String>();
                }
                return warningList;
            }
        }

        public bool HasWarnings
        {
            get
            {
                if (WarningList.Count == 0)
                {
                    return false;
                }
                else
                {
                    return true;
                }
            }
        }
    }

Then, in my service class I reference the CustomProcessorResult and add message to the List<String> WarningList:

using System;
using System.Collections.Generic;
using System.Text;

    /// <summary>
    /// Example class
    /// </summary>
    public class CustomProcessor : ProcessorBase
    {
        /// <summary>
        /// Process
        /// </summary>
        /// <returns></returns>
        public override IProcessorResult Process()
        {
           if(true)
           {
               ReportWarning("Some warning text");
           }
  
            return ProcessResult;
        }


        /// <summary>
        /// Report an error
        /// </summary>
        /// <param name="message"></param>
        private void ReportWarning(String warningMessage)
        {
           processorResult.WarningList.Add(warningMessage);
        }

        /// <summary>
        /// ProcessResult for this process
        /// </summary>
        public override IProcessorResult ProcessResult
        {
            get
            {
                if (processorResult == null)
                {
                    processorResult = new CustomProcessorResult ();
                }
                return processorResult;
            }
        }

        private CustomProcessorResult processorResult;
    }
 

 I haven't compiled any of the above code, but hopefully it gives you an idea. Please let me know if you have any more questions!

Cheers,

 Evan

Hi Evan,

Thanks a lot. It works perfectly, but I am getting strange problem. Sorry I am bit new to this.

In the aspx page where I am using it, what we are doing if the Insert is successful then we are redirecting it to same page in updae mode. Basically we are using FormUtil class for that.

So if we have a successful insert it come up with a blank, but if there is an error it shows the error message. I feel it looses the Datasource current entity after successful insert and the Forutil class is not able to create the querystring.

Hi Evan,

Don't worry, I found a way to redirect after a successful insert. I write that part of code in After_Inserted event.

Thanks a lot of your output.

Cheers

Vijay

 Can you share with us what you did for the benefit of others.

Thanks

swin