Model-Glue is a very powerful and robust ColdFusion Framework. When solving application problems with Model-Glue there are recurring solutions that work well for particular problems. Up until now, one would have to troll the various blogs hoping the right keywords unlocked google to reveal a proper solution. While effective, this method is also time consuming.

Todd Sharp has developed and released the Model-Glue cookbook. Following the common cookbook format, this timely and relevant application will hold collective wisdom on how to use the Model-Glue framework for fun and profit.

If you want to learn more about Model-Glue, please check the Model-Glue cookbook for interesting tips and solutions for everyday programming. It even has an RSS feed for you!

If you are a Model-Glue expert, or you have found some interesting solutions with Model-Glue, share them with the simple Entry Form. Adding an entry to the Model-Glue Cookbook is easier than blogging and you get full credit.

I admire Todd Sharp. He is an effective community leader, generous with his time and efforts. I mean, look at what he has done in just the last 3 months:

• CFEmmys
• Snip-a-thon contest
• PPTUtils Project
• cfsnippets.org
• Model-Glue Cookbook

Todd gets my vote for Most Deserving of Adobe Community Expert Status

Duplicating code is Bad! When designing software, take great pains to avoid duplication of code. After all, if an application has a lot of duplicated logic, or cut/pasted processes, it is very easy for parts of the system to get out of wack. A small tweak here, a short change there and next thing you know there are bugs and inconsistencies galore.

As software engineers, we are trained to spot and avoid this duplication. There are whole mantras dedicated toward this end (DRY Don't Repeat Yourself). There are whole books dedicated towards refactoring out commonalities for the goal of improving software quality. This is a very important topic and duplication is one of the easier Code Smells to uncover.

Sometimes the same warning flags will pop into mind when working with an XML driven framework. "Should I really duplicate this line of XML repeatedly in my application?" and "Am I designing my application effectively?" are thoughts the reasonable programmer has. After all, if duplicating code is such a poor idea, why is duplicating XML configuration any different?

The reason it is different is what the underlying XML represents. It represents Code! Code that has been written and tested and debugged Code that performs vital purpose in your application. We aren't duplicating this code, we are duplicating a reference to the code. A type of shorthand, if you will.

If, for example, you have functionality for checking for an authorized user, and such code is wrapped into an XML snippet like this:

Properly designed XML configurations represent complex processes in a syntactically simple manner. So feel good about duplicating your lines of XML. Happy Coding!

Previously, we connected Transfer ORM into our ContactOMatic application. Now, we will use it to get some things done! The completed files for this exercise are included at the bottom of the post, just click on the 'Download' link.

Using Transfer with MG:U is quite different than hand coding all the data access instructions so I separated out the new Transfer enabled code from the old hand coded bits to help compare similar operations between the two styles. This means the ContactOMatic is not an example of Architectural Purity! Shock! Horror! Gasp!

To make the separation, I added another ModelGlue configuration file, named ContactAction.xml, to the main ModelGlue.xml file through the use of the include tag as follows:

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Today we will install the Transfer ORM inside our Contact-O-Matic application. To complete this tutorial, you should have the Contact-O-Matic installed and running. If you have not completed this step, please create the database described at the bottom of Series 6 and install the files at Series 10 download link. Test the application by manually adding several ContactTypes to the ContactType table in your database (I chose Co-Worker, Enemy, Friend). Then use the Contact Form in the ContactOMatic application to enter a few contacts.

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I am going to continue the 'So You Wanna Create a Model Glue Application series. (Thanks Lola ;) For those just tuning in, the Contact-O-Matic is a simple example of a mini-application using ModelGlue and ColdSpring. The tutorials on the Contact-O-Matic go through the code line by line showing how to perform such tasks as:

1. Set up the frameworks
2. Build a View
3. Place your CSS and JS files
4. Create a form
5. Validate a submitted form and persist the data
6. Return success/error messages
7. Resolve CFC dependancies with ColdSpring
8. Create Instance Objects with factories
9. Refactor, as needed

The Contact-O-Matic is not an example of a Best Practices- Enterprise application. This is due to the simple nature of the program. We simply have a list of contacts, a mechanism to add and edit contacts, and a way to remove contacts. As Object Models grow complex in complex applications, it is important to note that there is no perfect Object Model, only the least annoying set of tradeoffs. I want the code in the Contact-O-Matic to remain simple, and so it shall.

Our next move is to integrate Transfer ORM into our application. The next set of posts will cover installation and testing of the Transfer ORM Framework, the inclusion of another 'Contact-O-Feature' in our application as well as some Architectural Techniques.

Sean Corfield pointed out that using ColdSpring to make instance (throwaway) components is quite a heavyweight approach for a simple form bean. He is, of course, correct. Our ContactFormBean is currently created by ColdSpring. In this series, we will add a factory object that will make our instance beans for us. The factory itself will be configured through ColdSpring as well as the configuration for our objects.

This is a very simple factory. It has three methods, GetConfig, SetConfig and getBean. In turn:

1. getConfig() returns a struct with keys = objectnames, and values = paths
2. setConfig() provides an interface for ColdSpring to set the configuration struct.
3. getBean() gets the path for a specific object from the configuration struct and returns a created object.

To use this instance factory, add the following ColdSpring xml snippet to the ColdSpring.xml file.

Now remove the original ContactFormBean configuration.

Next, open the Controller.cfc file and change each instance (getContactForm, handleContactForm and removeContact) of getModelGlue().getBean("ContactFormBean") to getModelGlue().getBean("InstanceFactory").getBean("ContactFormBean") .

Finally, reinitialize your application and click on the ContactForm tab. You should see your form as before.

A factory might seem like overkill right now, since this is a simple application. However, Factory objects are a good pattern to learn. Our motivation for the factory in this case was to reduce the amount of unnecessary processing incurred by using ColdSpring to make a simple form bean. We could however, expand our factory to take additional parameters and create all sorts of dynamic objects for us.

In a later series, we'll do just that.

In our last segment we built the functionality to store our contacts to the database. Now we need a way to edit the information because after all, friends can become enemies, and enemies can become co-workers. We have a good structure in place and these changes will be simple.

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In our last series, we moved the ContactTypes from a ColdSpring configured struct, to a database table. This set the stage to move the rest of our persisted data to the database.

As we begin this series our main goal is to have our contacts and lists of contacts stored in our database. Originally, we used in-memory storage as it allowed us a functional application without a database.

In this series, we will introduce two new files, ContactDAO and ContactGW (GW = Gateway). Both components will reside in the *ContactManagerMG.model directory. The ContactDAO will handle the DB work for Creating, Reading, Updating and Deleting our Contacts. Incidentally, this group of functionality is commonly referred to as C.R.U.D. The ContactGW will handle the database work for pulling queries of Contacts. We'll have a function called getContactQuery().

Here is a look at the ContactDAO. Note: we reference the AppConfig inside our ContactDAO so we can use the Application Configuration defined in ColdSpring. While we mostly care about the DSN for now, the flexibility to pull other configuration parameters will come in handy later.

Here is a look at the ContactGW. Once again we reference the AppConfig.

Now we add each component to our ColdSpring configuration. Each component takes one Property, the AppConfig object. Add both beans as new property tags to the existing ContactService bean definition. We will also remove the references to the old Array based ContactList. Let's do a little housecleaning on our ColdSpring file shall we?

Add the definitions for the components

Remove the following lines from the existing ContactService definition:

Add in the property tags for our new components.

Once complete, ColdSpring will run setContactDAO() and setContactGW() on the ContactService component and stuff the proper object in our service for us. We need to change the service a little now to account for this new functionality. Open up the ContactService and make the following changes:

Remove the getContactList() and setContactList() functions. These functions used to manage our Array based contact list from ColdSpring, with our new Database driven Contact-O-Matic, we won't need them any longer.

Remove:

Now add in the get/set functions for each component. While we are in here, also add in a new function to get our ContactList from our new ContactGW. The function on the ContactGW is called getContactQuery(). When complete, you'll have removed two functions and added five. Examples of the new functions are below:

Now our service has references to the ContactDAO and the ContactGW, in turn both the ContactDAO and ContactGW have references to our AppConfig. All the plumbing for the database interaction is complete.

Previously, we stored the ContactType in our ContactFormBean. This was acceptable when referential integrity was not on our list. Now, we need to modify the Contact Form and the Contact Form Bean to refer to the ContactTypeID instead of simply the ContactType. In the form itself, all we need to do is switch the reference. Inside the Bean there is a tiny bit more to it. We will start with the form.

The select tag block should be changed as follows

Now open the ContactFormBean and change all the ContactType references to ContactTypeID. A find and replace would be nice here. A simply Find and Replace should make 11 changes...

There are two references in the Init() function, one in the validate function and also a get/set block at the bottom. Each of these should be changed to ContactTypeID.

The completed ContactFormBean is here:

Finally, we need to change how the contacts are saved. In the beginning, we simply appended the ContactFormBean object into an Array of ContactFormBean object and iterated over the array for our ContactList. Now, we need to change the controller function to call the service. We will let the service decide how to handle the save. In the controller located at *ContactManagerMG.controller modify the isvalid branch to call a ContactService method called saveContact()

Now add the saveContact() function into your ContactService. This function will accept a Contact object, being our ContactFormBean, and check to see if the ContactID has been assigned. If so, we will update the record, if not, we will create the record. Your saveContact() function should look like this:

After changing the save contact flow, we have closed the circle for adding / updating the individual contacts. Remaining, is the ContactList page.

We will now be returning a query and ourcontact list page used to operate on an array. Thus, we must adjust.

Change your dspContactList.cfm page to use a query. Your completed list page will look as follows:

Reset your application and run your new Database Powered Contact-O-Matic. If you've followed all the steps, (and I haven't left any out) you now have a proper application.

We touched a good chunk of the application and I trust this has been a good refresher into the inner workings of our Contact-O-Matic. In our next series, we will include the mechanics to delete contacts from the database.

We are going to break this up into phases starting with the contact types. At the end of this series, our contact types will come from the database and we will have an even greater appreciation for ModelGlue and ColdSpring.

The last article gave the spec for your database tables, Contact and ContactType. Add in 3 dummy records to the ContactType table. I used Friend, Enemy and Co-worker.

Set up your datasource in the ColdFusion administrator. I used the data source name of 'ContactOMatic'. Test the connection and move on.

Now we will need this datasource name inside of our cfqueries. Can anyone guess where we will keep the DSN? Thats right, in ColdSpring. Give yourself a cookie if you got that one right.

Before we begin, change the ColdSpring.xml ModelGlueConfiguration reload setting to true.

ModelGlue has a standard component called a SimpleConfig. The purpose of the simple config is to hold on to a collection of values and this component is easily configured in ColdSpring. The path for SimpleConfig is ModelGlue.bean.CommonBeans.SimpleConfig, so add a configuration to ColdSpring for this. We will refer to this as AppConfig and it will hold our DSN and an AppTitle.

Run your application. If you have an error at this point, check the exact path to the SimpleConfig component. No errors? Perfect!

Simple enough so far, right? Now we shall write our ContactTypeGW. This component will pull a query of ContactTypes from the database. There are three functions in the ContactTypeGW.

1. setAppConfig - this function provides the way for ColdSpring to stick the AppConfig component in the ContactTypeGW
2. getAppConfig - this function provides a way for us to reference the AppConfig component inside the ContactTypeGW
3. getContactTypeQuery - this function returns the ContactTypes from the database

Your ContactTypeGW should look like this:

Note for the DSN we used 'getAppConfig().getConfig().dsn', when we want to access the AppTitle later, we'll use 'getAppConfig().getConfig().AppTitle'. (If you haven't seen this syntax before, getAppConfig() returns a reference to the AppConfig Object, which has a getConfig() function returning a struct. Then we access a property of the struct using dot notation.)

Now, adjust the ContactService to call ContactTypeGW. Remove the following functions: init, getContactTypes and setContactTypes. Add get and set functions for our ContactTypeGW. Then add the proper function for getContactTypes. It should return a query so be sure to adjust the returntype to 'query'

Your ContactManangerService should look like this:

Now adjust ColdSpring to account for the new gateway functionality. Configure the bean definition for ContactTypeGW and add the AppConfig property. Replace the ContactType map with the ContactTypeGW bean The changed lines should look like this:

Finally, our contact form was expecting a struct, it will now get a query so adjust the ContactType section accordingly

Remember to reinitialize your application and now run your code. You should now see the ContactTypes defined in your database

It seems like we touched a few files to make this change. We altered the ColdSpring.xml file to have an application configuration object, added in our ContactTypeGW and then stitched them together. We also had to adjust our form to account for a query in place of the struct. Note we did not touch our Controller nor our ModelGlue.xml file. Since the flow of the application did not change, those files remain the same and happily work with the new functionality of the application. This is an example of the benefits of compartmentalized, or encapsulated, code.

A zip of all files is included with this article.

Next, we will create the contact persistance and write our contacts to the database

In the next few series, our Contact-O-Matic will persist data in a database. The queries and relationships are simple and should translate over to any database. Our code will be organized into two types of components the DAO (Data Access Object) and the Gateway. These two components are common structures used in many Object Oriented systems and a quick google search will land you on endless descriptions for each. For our purposes, all we need to know is the DAO and Gateway will help us organize our code into sections. The DAO is for pulling back a single object, the Gateway for a query of objects.

Another architectural feature of our Contact-O-Matic is our ContactService.cfc component. Service components help tie your other components together. Note how simple it will be to add in new database functionality.

At the end of series 5 of our Contact-O-Matic, we had a ContactService component which returned the ContactType data , a single contact object and a list of contact objects. Even though we are going to add a DAO component as well as a Gateway component, they will be tied together within the service component.

Some of you might be asking yourselves why we have all of these components. After all, there are huge and complex ColdFusion applications written without a single component. Couldn't we just put our queries in the Controller and be done with it? That is a very valid question to ask. You should be proud of thinking of it. Question Everything!!!

The main point of these separations in our code is to isolate variability. Meaning, when the application needs a feature, or a new data column, the affected sections in our code are compartmentalized and perhaps only one section of code needs to change in order for the entire application to be upgraded with the newest feature.

The complete source code up to the end of series 5 is attached to this article. It will be easier to follow along if you use this code.

A few quick notes before we begin:

1. Remember that the application files will be cached if the ModelGlue reload setting is 'false'. Any changes to Controllers, components created with ColdSpring, or stored in the Controllers will NOT change until you reload the application. This trips me up sometimes and my first step is to ALWAYS reload the framework
2. The <include /> tag is processed by BlogCFC as a cfinclude. Thus, whenever I paste in an event-handler section with an <include tag, I always have to use the entity symbol '& lt;' or i'll get an error when I post it. I try to leave a small note at the end of the code block about changing this in your code. If I forget, just know an XML tag will never actually start with '& lt;'
3. I am writing this tutorial with MSSQL server (delete derogatory note about Microsoft Products). Your database might have a slightly different syntax and I trust you to convert it over

Lastly, our database will have two tables:

Without further ado, let us get to the next piece in our Series, database support.