LiveCycle Data Services Introduction

Part 2

Part 2?

• This is the second in our series on LiveCycle Data Services. If you missed our first presentation, it can be found at:– http://www.theFlexGroup.org/presentations.cf

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• Last time, we covered what LDS is, and some on LDS Messaging

Data Management

• Data Management is the component of the LiveCycle Data Services suite of services that allows for LDS to help you communicate and control the data to your end user

• Allows for Data Synchronization, Data Caching, Data Pagination, and Conflict Resolution.

Data Management

How it works:• Data is packaged up

into ‘Value Objects’, or packages of data.– This usually consists

of a “row” of data from a database

• Each VO is tracked separately as to who is viewing, editing, etc.

Data Management

• Users then Subscribe to a set of data.– LDS will then keep track

of the state of that data, and send it from the Application Server to the Flex Application.

• LDS will ‘listen’ to any changes made to the data in the Flex Client.

Data Management

• If the Collection that holds the data is changed in the client, LDS will take that change, change the Value Object in memory, send the change to the App server, and update all clients in real-time.

Data Management

• When an update is sent to the other clients, it will check its local copy, to make sure that record has not changed. If it has, it will issue a “Conflict” event, and allow the Client to choose what to do.

Data Management

• On the Client, 95% of your work is handled by any of the Collection classes, such as the ArrayCollection

• Handles updating LDS with Changes, and notifying other visual components of changes.

Data Management

• When a DataGrid, or InputBox broadcast the Change event, the ArrayCollection hears it, and updates its own data, and passes the change to other components that subscribe to its change event.

Building an Application

• We will be building a quick “CMS” application utilizing a simple DataGrid and some buttons…– Backend will be ColdFusion and Microsoft

Access– LiveCycle 2.5 will be used– Flex SDK 2.0.1 will be used inside Flex

Builder 3 beta 2.

Building an App

• First, we will want to create a new database file in Access. We will be using the “Contacts” template to create the file.– Normally, we would create a custom database

file for this purpose.– If using Access 2007, make sure to save the

file as an Access 2003 or Access 2000 file.

Building an App

• Next, we will want to add the new Database as a ‘Datasource’ in ColdFusion– Named “ug_contacts”, using the Access

Unicode Driver

• Load up Flex Builder, and create a new Flex Project– Web Application, ColdFusion App Server,

LiveCycle Data Services

Building an App

• Create a new folder on the server for the ‘Value Objects’, \bin\cfcs\

• Create a new AS Class folder : \src\ascript

• Open the RDS view, and find the Contacts table

• Right-Click on Table, ColdFusion Wizards, Create CFC

Building an App

• CFC Folder:– /contact_cms/bin/cfcs

• CFC Package Name:– contact_cms-debug.cfcs

• CFC Type:– LiveCycle DS Assembler

• Create AS-VO– AS Folder: \src\ascript

Building an App

• Next, we need to modify the LDS configuration files to tell LDS about the components we just created.– File is in the wwwroot\WEB-INF\Flex\

directory, named data-management-config.xml

• Add a new entry (Destination) to represent the component we just created.

Building an App

• Destination.properties.component– Component dot path on the CF server

• Destination.properties.scope– Application or request

• Destination.properties.metadata.identity– Set this to the key field in your table

• Destination.properties.metadata.query-row-type– This is the path to the ActionScript Value Object

we created.

Building an App

• Restart LiveCycle Data Services, and make sure there are no errors– If using the bundled LDS with ColdFusion,

restart the CF Application Service

• Now, we just need to create the client, and we are done!

Building an App

• Open your MXML document, and add a <mx:DataService> tag– Give it an ID, and the Destination that we

used in the last step

• Add a new ArrayCollection variable (to hold your data)

• Add a new function to execute the DataService.fill(arrayCollection);

Building an App

• Next, add a DataGrid and at the very least, a button to trigger the fill() command.

• Bind this DataGrid to your ArrayCollection, and set the editable property to true.

• Also, open up the Contacts.as file, and notice the [Managed] metadata. This code tells the AS to broadcast its changes to outside components.

RUNNING THE APPLICATIONConnect to http://kwiatk27.msu.edu:8500

Running the Application

• If you update the data in one application, the data becomes updated in any other instances of the Flex Client, in real time!

• What if you wanted to queue the changes, or allow the user to back out of the changes before they occur?

Turning off AutoCommit

• In order to allow the clients to queue changes, and control when they commit the changes, we need to turn off the AutoCommit feature of the DataService

• Add the autoCommit=“false” declaration to the DataService component.

• We will now need to add two buttons to allow the user to commit their changes.

Turning off AutoCommit

• Add two additional buttons:– Name one Apply, with a click event of :

dataService.commit();– Name the second Cancel, with a click event of

: dataService.revertChanges();

AUTO-COMMIT DEMOhttp://kwiatk27.msu.edu:8500

Adding and Removing Items

• Adding and removing items to the database is as trivial as adding a new item to the ArrayCollection.– Remember when adding an item, you may

need to turn off the AutoCommit feature, as your database may not allow null values.

• ArrayCollection.addItem(new className());• DataService.deleteItem(dgContacts.selecte

dItem);

Conflicts

• Another nice thing about Data Management is the ability to have Conflict Resolution built right into your application.

• LDS can trigger an event when another user updates a record you are currently updating

• Add the “conflict” event handler to the DataService to create your own conflict handler.

Conflict

• When handling a conflict, you have the option to update with your version, take the server’s version, or to let the user choose what version to keep.

• Lets show how to detect a conflict in data sets, notify the end user, overwrite the client’s data with the server’s version.

CONFLICT RESOLUTIONhttp://kwiatk27.msu.edu:8500

Fill Queries

• Using the ‘out of the box’ data management is great if you want to return full sets of data– But what happens if you want to return only a

portion of your full table; for example a search result?

• You can customize your fill parameters by modifying your assembler’s Fill() function and passing the fill as the second parameter of the call.

Fill Queries

• For example:– DataService.fill(ArrayCollection,SearchString:

string);

• Translates to:– <cffunction name=“fill”>

• <cfargument name=“searchString”…./>

– </cffunction>

Paging

• What happens if you have too much data returned from a query to send down to the clients?– For example, do you really want to send

50,000 records down the pipe?

• LDS has a built in Paging mechanism!

Paging

• To configure it, edit your data-management-config.xml file.– Destination.properties.network

• <paging enabled=“true” pageSize=“xxx”/>

• That is all you have to do!

PAGING & QUERIEShttp://kwiatk27.msu.edu:8500

Questions?

kwiatk27@msu.edu