AdvancedDataGrid - Adventures in Binding
Written on 18 September 2008 by JoshuaQuick post on AdvancedDataGrid dataProviders.
If your using a HierarchicalData provider for you AdvancedDataGrid (Flex) binding changes may (will) not be picked up by the AdvancedDataGrid.
For example
<mx:AdvancedDataGrid id="grid" bottom="10" top="40" left="10"
designViewDataType="tree" width="379">
<mx:dataProvider>
<mx:HierarchicalData source="{grades}"
childrenField="assignments"/>
</mx:dataProvider>
<mx:columns>
<mx:AdvancedDataGridColumn headerText="Course" dataField="title"/>
<mx:AdvancedDataGridColumn headerText="Score" dataField="scoreString" width="80"/>
</mx:columns>
</mx:AdvancedDataGrid>
Won’t pickup the update to ‘grades’. Instead you’ll need to update the dataProvider itself…
var hd:HierarchicalData = new HierarchicalData();
hd.childrenField = "assignments";
hd.source = grades;
grid.dataProvider = hd;
Bindable Read-Only Getters
Written on 8 September 2008 by JoshuaI had the opportunity to clear up some confusion on ‘bindable’ read-only ‘getters’ so I thought I’d post.
If you mark your ActionScript class [Bindable], the compiler will generate propertyChange events for the class’s public variables and properties exposed through getters and setters.
When a property exposed through a get / set pair is modified, a propertyChange event will be dispatched (from the setter). Use the comiplers -keep flag to inspect this for yourself.
If you have a property exposed through a getter but no matching setter, data binding will not detect changes to the ‘get’ value.
For example, you might have a getter value that is calculated from two other fields. To enable data binding on the ‘getter’ value, simply dispatch an event whenever the fields in the calculation are updated. You can then mark the getter function Bindable on those event names.
Here’s a working example
package
{
import flash.events.Event;
[Bindable]
public class BindingDemo
{
private var _numerator:Number = 0;
private var _denominator:Number = 1;
public function get numerator():Number
{
return _numerator;
}
public function set numerator(value:Number):void
{
if(value != _numerator)
{
_numerator = value;
this.dispatchEvent(new Event('numeratorChanged'));
}
}
public function get denominator():Number
{
return _denominator;
}
public function set denominator(value:Number):void
{
if(value != denominator)
{
_denominator = value;
this.dispatchEvent(new Event('denominatorChanged'));
}
}
[Bindable(event=’numeratorChanged’)]
[Bindable(event=’denominatorChanged’)]
public function get ratio():Number
{
if(_denominator == 0)
return 0;
return _numerator / _denominator;
}
}
}
And some MXML to try it out
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
[Bindable] public var bdemo:BindingDemo = new BindingDemo();
]]>
</mx:Script>
<mx:Button x="193" y="23" label="Update" click="bdemo.numerator=Number(nvalue.text)"/>
<mx:Label x="20" y="25" text="Numerator"/>
<mx:Label x="20" y="51" text="Denominator"/>
<mx:Label x="30" y="90" text="Numerator" fontWeight="bold"/>
<mx:Label x="17" y="116" text="Denominator" fontWeight="bold"/>
<mx:Label x="62" y="142" text="Ratio" fontWeight="bold"/>
<mx:Label x="105" y="90" text="{bdemo.numerator}" id="num"/>
<mx:Label x="105" y="116" text="{bdemo.denominator}" id="den"/>
<mx:Label x="105" y="142" text="{bdemo.ratio}" id="ratio"/>
<mx:TextInput x="105" y="23" width="80" id="nvalue"/>
<mx:TextInput x="105" y="49" width="80" id="dvalue"/>
<mx:Button x="193" y="49" label="Update" click="bdemo.denominator=Number(dvalue.text)"/>
</mx:Application>
Try it out below.
PHP ODBC across networked drives
Written on 20 August 2008 by JoshuaWhile integrating some backend services needed by our RIA I ran across a small hiccup that was easily fixed but I thought I’d post in case someone else get’s stumped by this (apparently some already have ).
Problem:
PHP needed access to and ODBC connection that pointed to a dBase III database on a remote server. While local applications could use this ODBC connection flawlessly, connection via PHP failed.
Symptons:
Warning: odbc_connect() [function.odbc-connect]: SQL error: [Microsoft][ODBC dBase Driver] ‘(unknown)’ is not a valid path.
Solution:
You need to enable rights for the Apache Service to have access to the remote directory.
For my particluar situation the server running apache and php was not part of the domain, so I simply right clicked on the apache service, navigated to the Log On tab and selected “This Account” (and filled in the administrator credentials) as opposed to the default “Local System Account.”
Flex Modules, Watch Your Scope!!
Written on 14 August 2008 by JoshuaHere’s another help hint for those working with Modules in Flex: Watch your variable scope!!
When loading modules, you have a number of options for loading the SWF including the ModuleLoader and ModuleManager. If neither of those fit your needs you always have access to Flash’s Loader class. ModuleManger can be used for fine grained control of the loading process. Either way, variable scope plays a crucial roll in the loading process.
Here’s an example using ModuleLoader…
public function loadSWFModule(swfURL:String):void
{
var moduleLoader:ModuleLoader = new ModuleLoader();
moduleLoader.url = swfURL;
moduleLoader.addEventListener(ModuleEvent.READY,onModuleLoaded);
moduleLoader.addEventListener(ModuleEvent.ERROR,onModuleError);
moduleLoader.addEventListener(ModuleEvent.PROGRESS,onProgress);
moduleLoader.loadModule();
}
The moduleLoader is declared as a local variable. As it turns out this will cause problems, even with the ’strong’ event listeners. For those not wanting to read the technical details to follow, simply use avoid using a locally scoped variable.
The following are some of the symptoms you may run into using the latter locally scoped variable:
To help those searching the net, I’ll be a bit redundant in the ’symptom’ descriptions so hopefully you’ll find this post if you’ve stumbled upon this problem
Symptons
The problem comes in when the Loader finishes loading the SWF. ModuleInfo’s internal listener list (listeners attached during ModuleInfoProxy’s constructor) are lost (i.e. null) when ModuleInfo finally reaches it’s readyHandler( ) method. At the end of the readyHandler( ), a ModuleEvent.READY event is dispatched.
dispatchEvent(new ModuleEvent(ModuleEvent.READY));
With the listener list being null, the event is never picked up by the ModuleInfoProxy and the initial load fails.
On subsequent loads (i.e. the second time) ModuleInfoProxy’s load( ) method checks to see if the info has already been loaded and dispatches the ModuleEvent.READY event directly.
else if (info.loaded)
{
//trace("Module[", url, "] load is already loaded");
if (info.setup)
{
...
if (info.ready)
{
...
dispatchEvent(new ModuleEvent(ModuleEvent.READY));
}
}
}
Causing the load to ‘work’ the second time.
My understanding is that Garbage Collection is often invoked when a module is loaded. It looks like it’s the cause of this behavior (the listeners being lost). I assumed that the ’strong’ listeners would be enough to keep the GC away, oh well.
Again the solution is simple, make sure your not using a locally scoped variable when loading modules.
Flex, Java Remoting, and JMS [null message body]
Written on 7 August 2008 by JoshuaSo I was pounding out some code this afternoon, ran into a small snag and thought I’d post. Neuro-physiologists tell us that we better remember what we write down so here goes.
Similar to my post a few months ago, I made a simple omission in my coding flurry.
I was working with a backend Java class that published messages to [ActiveMQ] JMS. I wrote up a simple VO class to publish via JMS.
package com.dl.sifagents.vo;
import java.io.Serializable;
public class ZISEventVO implements Serializable
{
public String eventType = "";
public String payloadPackage = "";
public String payloadElement = "";
public String xml = "";
}
On the Flex side, I wrote up an AS3 implementation
package com.dl.sifagents.vo
{
[RemoteClass(alias="com.dl.sifagents.vo.ZISEventVO")]
[Bindable]
public class ZISEventVO
{
public var eventType:String;
public var payloadPackage:String;
public var payloadElement:String;
public var xml:String;
}
}
I published the VO to JMS…
public void publishObjectToJMS(Serializable o)
{
try {
ObjectMessage message = _pubSession.createObjectMessage();
message.setObject(o);
_publisher.publish(message, Message.DEFAULT_DELIVERY_MODE, Message.DEFAULT_PRIORITY, 5 * 60 * 1000);
} catch (JMSException e1) {
e1.printStackTrace();
}
}
I’d received the JMS message in Flex (via BlazeDS) but the message body was null. I checked and doubled checked my Java VO implementation vs AS3 VO implementation and couldn’t find any naming conflicts or errors.
Then it hit me, in my haste I’d forgotten to upload the Java VO class to BlazeDS (i.e. to the WEB-INF/classes folder)!
That’s my piece of humble pie for the week 
Back to work.
Dashboards… Flex’s ‘Sweet Spot’
Written on 6 August 2008 by JoshuaThanks Adobe!!!
I’ve taken on a number of Flex projects over the past 2-3 years. In that time I’ve used Flex to meet many types of business needs. I’ve spent the last few months working on a enterprise dashboard application built with Flex. This past week the time came for the executives’ ’sneek peek’ of the project’s progress. The feedback, in their words,
“Beyond all expectation.”
I can’t remember having more fun architecting and implementing a project. Dashboards seem to be Flex’s ’sweet spot’, IMHO. Adobe [Flex] provides so rich a toolset for this type of project, one can’t help but have fun working on dashboards with Flex. Talking with other local Flex developers only resonates the view that Flex + Dashboards are a perfect fit. So once again, thanks to Adobe for this great product, it’s been an absolute joy to work with.
FYI, the project is using Flex, AMFPHP 1.9, ActiveMQ JMS + BlazeDS, Multicore PureMVC, PureMVC’s Pipes, MySQL to name a few (i.e. a mouthful of open source technologies). BTW, it scales beautifully with dynamic modules using PureMVC Pipes. Thanks too, to Cliff Hall for PureMVC!!
For those pessimists our there, I can post again once I’ve developed the printouts (Printing is notoriously painful in Flex :)).
[Tunkey] BlazeDS + JMS + ActiveMQ
Written on 1 August 2008 by JoshuaI spent some time this week with BlazeDS and JMS. I wanted to integrate a Flex RIA with some [existing] backend Java classes. One goal was to interface the two in a loosely coupled fashion, enter Java Message Service (JMS).
The RIA uses a mx:producer to publish messages to a JMS topic which the backend Java class is listening in on [consuming] elsewhere in the enterprise. I used an ‘external install’ of ActiveMQ.
I downloaded the turnkey BlazeDS server to get things rolling.
I came across a few great posts in looking into this…
Michael Martin’s Simplified BlazeDS and JMS
Christophe Coenraets
Flex and JMS: Portfolio Viewer (LCDS jRun)
30 Minutes Flex Test-Drive for Java Developers (FDS)
To be helpful, I’ve included some error messages and their causes:
Flex Runtime Error:
There was an unhandled failure on the server. MessageClient has been invalidated.
Cause: ActiveMQ not running.
Flex Runtime Error:
Client.Message.Encoding
Type ‘com.dl.samples.PersonVO’ not found.
Cannot create class of type ‘com.dl.samples.PersonVO’.
Cause: Java classes not on server.
Java Runtime Error
javax.naming.NameNotFoundException: messageTopic
at org.apache.activemq.jndi.ReadOnlyContext.lookup(ReadOnlyContext.java:225)
at javax.naming.InitialContext.lookup(Unknown Source)
at Chat.
at Chat.main(Chat.java:27)
Cause: jndi.properties not present for java class
Java Runtime [BlazeDS] Error
[BlazeDS] JMS consumer for JMS destination ‘[destinationName]’ is being removed from the JMS adapter due to the following error: Name jms is not bound in this Context
[BlazeDS] JMS consumer for JMS destination ‘[destinationName]’ is stopping.
[BlazeDS] The corresponding MessageClient for JMS consumer for JMS destination ‘[destinationName]’ is being invalidated
Cause: context.xml Resource names do not match messaging-config.xml connection-factory / destination-jndi-name tags. (i.e. the ‘org.apache.activemq.ActiveMQConnectionFactory’ resource name in context.xml should match the connection-factory value in messaging-config and the ‘org.apache.activemq.command.ActiveMQTopic’ resource name in context.xml should match the destination-jndi-name value in messaging-config).
Adding the logging pattern ‘Service.Message.JMS’ to your services-config.xml can be very helpful in debugging BlazeDS JMS problems.
Here are the config files
C:/blazeds/tomcat/webapps/MyApp/WEB-INF/flex/services-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<services-config>
<services>
<service-include file-path="messaging-config.xml" />
</services>
<security/>
<channels>
<channel-definition id="my-amf" class="mx.messaging.channels.AMFChannel">
<endpoint url="http://localhost:8400/BlazeTest/messagebroker/amf" class="flex.messaging.endpoints.AMFEndpoint"/>
</channel-definition>
</channels>
<logging>
<target class="flex.messaging.log.ConsoleTarget" level="Debug">
<properties>
<prefix>[BlazeDS] </prefix>
<includeDate>false</includeDate>
<includeTime>false</includeTime>
<includeLevel>false</includeLevel>
<includeCategory>false</includeCategory>
</properties>
<filters>
<pattern>Endpoint.*</pattern>
<pattern>Service.*</pattern>
<pattern>Configuration</pattern>
<pattern>Service.Message.JMS</pattern>
</filters>
</target>
</logging>
</services-config>
C:/blazeds/tomcat/webapps/MyApp/WEB-INF/flex/messaging-config.xml
<?xml version="1.0" encoding="UTF-8"?>
<service id="message-service" class="flex.messaging.services.MessageService">
<adapters>
<adapter-definition id="actionscript" class="flex.messaging.services.messaging.adapters.ActionScriptAdapter" default="true" />
<adapter-definition id="jms" class="flex.messaging.services.messaging.adapters.JMSAdapter"/>
</adapters>
<default-channels>
<channel ref="my-amf"/>
</default-channels>
<destination id="simpleJMS">
<properties>
<jms>
<destination-type>Topic</destination-type>
<!--<message-type>javax.jms.TextMessage</message-type>-->
<message-type>javax.jms.ObjectMessage</message-type>
<connection-factory>java:comp/env/TopicConnectionFactory</connection-factory>
<destination-jndi-name>java:comp/env/messageTopic</destination-jndi-name>
<delivery-mode>NON_PERSISTENT</delivery-mode>
<message-priority>DEFAULT_PRIORITY</message-priority>
<acknowledge-mode>AUTO_ACKNOWLEDGE</acknowledge-mode>
<initial-context-environment>
<property>
<name>Context.INITIAL_CONTEXT_FACTORY</name>
<value>org.apache.activemq.jndi.ActiveMQInitialContextFactory</value>
</property>
<property>
<name>Context.PROVIDER_URL</name>
<value>tcp://localhost:61616</value>
</property>
</initial-context-environment>
</jms>
</properties>
<channels>
<channel ref="my-amf"/>
</channels>
<adapter ref="jms"/>
</destination>
</service>
C:/blazeds/tomcat/webapps/MyApp/WEB-INF/web.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>BlazeDS</display-name>
<description>BlazeDS Application</description>
<!-- Http Flex Session attribute and binding listener support -->
<listener>
<listener-class>flex.messaging.HttpFlexSession</listener-class>
</listener>
<!-- MessageBroker Servlet -->
<servlet>
<servlet-name>MessageBrokerServlet</servlet-name>
<display-name>MessageBrokerServlet</display-name>
<servlet-class>flex.messaging.MessageBrokerServlet</servlet-class>
<init-param>
<param-name>services.configuration.file</param-name>
<param-value>/WEB-INF/flex/services-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>MessageBrokerServlet</servlet-name>
<url-pattern>/messagebroker/*</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
C:/blazeds/tomcat/webapps/MyApp/META-INF/context.xml
<?xml version="1.0" encoding="UTF-8"?>
<Context path="/BlazeTest">
<Resource name="TopicConnectionFactory"
type="org.apache.activemq.ActiveMQConnectionFactory"
description="JMS Connection Factory"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
brokerURL="tcp://localhost:61616"
brokerName="myBroker"/>
<Resource name="messageTopic"
type="org.apache.activemq.command.ActiveMQTopic"
description="a simple topic"
factory="org.apache.activemq.jndi.JNDIReferenceFactory"
physicalName="messageTopic"/>
</Context>
Using the above messaging-config’s destination the message will come across as an ObjectMessage in Java
Ensuring Windows Services can access Novell NetWare directories
Written on 1 August 2008 by JoshuaEnded up spending some time getting this to get this to work last week. We had some Windows services running on a Windows Server (Server 2003) that needed to access data on a NetWare volume. While a logged in user could access the data on the NetWare server, the windows service could not (or was intermittent at best).
Here’s what I found - hope someone finds it helpful.
Per Microsoft - Windows services should use UNC paths not Mapped Drives
http://support.microsoft.com/kb/180362/EN-US/
Novell’s direction on getting MS Service applications to access NetWare volumes if the service was written in a non-novell-aware manner.
http://www.novell.com/support/viewContent.do?externalId=7000312
After following the latter directions everything is working great.
Time to get back to some RIA development
AMFPHP Class Mapping Primer [1.9 beta]
Written on 1 July 2008 by JoshuaThought I’d post a simple AMFPHP class mapping primer.
I ran into a wall after re-arranging my VO / DAO package structure on the server, learned a few things in the process and thought I’d post .
I’m assuming your using AMFPHP 1.9 beta.
Class mapping allows your php backend and actionscript frontend to pass strongly typed variables back and forth. The benefits are obvious so I won’t cover them here.
If your not after any detailed information here’s a quick set of samples classes to get you going.
PHP
// LoginVO.php is saved as {$voPath}/com/dl/app/LoginVO.php
class LoginVO
{
var $_explicitType="com.dl.app.LoginVO";
public $username;
public $password;
}
AS
package com.dl.common.Login.model.vo
{
[RemoteClass(alias="com.dl.app.LoginVO")]
public class LoginVO
{
public var username:String;
public var password:String;
}
}
That’s it. If your after more options and detailed info, keep reading.
Sending Strongly Typed Objects from PHP to ActionScript via AMFPHP
In PHP
You have a few options (choose one).
The most common approach is to use the $_explicitType class member:
class LoginVO
{
var $_explicitType="com.dl.app.LoginVO";
public $username;
public $password;
}
e.g.
$GLOBALS['amfphp']['outgoingClassMappings']['myclass'] = "com.dl.myapp.MyClass";
Note that the local class name associative key (’myclass’ above) must be in lowercase with the current release of AMFPHP.
If your install of PHP has the ReflectionAPI you can let AMFPHP do the work *for* you. I found a few cavets using this approach on servers who’s OS uses backslashes natively. If this is the case, AMFPHP will only send the name of the class and not include any package info. There are two simple code changes you can make in AMFPHP to get around this, just drop me a line if your interested (hopefully they’ll be commited in the next release of AMFPHP).
In actionscript
Here to, you have a some options,
package com.dl.common.Login.model.vo
{
[RemoteClass(alias="com.dl.app.LoginVO")]
public class LoginVO
{
public var username:String;
public var password:String;
}
}
registerClassAlias(”com.dl.app.LoginVO”,LoginVO);
Make sure your actionscript project contains a reference to the class. See my previous post for more info.
Sending Strongly Typed Objects from ActionScript to PHP via AMFPHP
In PHP
Rely on the class having been registed in ActionScript with the server’s correct package [directory] structure (relative to AMFPHP’s VO base path $GLOBALS[’amfphp’][’customMappingsPath’]). If this is the case you, your all set.
Define $GLOBALS[’amfphp’][’incomingClassMappings’][’remoteclassAlias‘] = ‘localclassPackage‘. (e.g. $GLOBALS[’amfphp’][’incomingClassMappings’][’com.dl.as3.userVO’] = ‘com.dl.userVO’);
In ActionScript
Again, you’ll need to use one of the two following…
For more info check out
AMFBaseSerializer.php’s getClassName() function
AMFBaseDeserializer.php’s mapClass() function
AMFPHP Complex Classes - Yeah I knew that
Written on 19 June 2008 by JoshuaJust blew half an hour tracking down something I *knew* I’d done before. Thought I’d post here for future ‘lapses.’
To return a typed object from PHP to the flashplayer the process is simple, declare a variable called $_expicitType in your PHP class
e.g.
class SummaryVO
{
var $_explicitType = "com.dl.SummaryVO";
$standards = array();
$levels = array()
}
In your corresponding ActionScript class use the RemoteClass metadata tag
package com.dl
{
[RemoteClass(alias="com.dl.SummaryVO")]
public class SummaryVO
{
public var standards:Array;
public var levels:Array;
}
}
Note the values for $_explicitType and alias are arbitrary, they can be what ever you’d like, as long as their the same in AS and PHP (provided your only conerned with PHP=>AS mapping).
Okay, so what happens when you have ‘complex classes’ you’d like to return? Complex meaning a class who’s members are made up of other ‘custom’ class instances.
Let’s say, for example, that in our later code example ’standards’ was an array of ‘StandardVO.’ The problem I ran into was that I was getting a typed ‘SummaryVO’ back from AMFPHP, however my class members were not typed, just generic objects. I checked and I had taken the necessary steps to use strongly typed SummaryVO and StandardVO classes, yet the StandardVO was coming back as a plain old Object.
We’ll it turned out in my development flurry I hadn’t used a reference to the ‘StandardVO’ class yet!! Simply declaring an instance of StandardVO did the trick (i.e. var placeHolder:StandardVO). You could also you the includes class […] compiler option.
Moral of the story, be sure the complier includes a reference to any class you want strongly typed from your RPCs.
Pipe Demo: Mortgage App
Written on 17 June 2008 by JoshuaI’ve posted a pipes version of the mortgage app.
Things to note:
You can load / unload the modules dynamically.
A junction mediator is defined for each ‘player.’ In the mortgage app context that’s a mediator for the application itself, the Acme widget and the Foo widget.
ApplicationJunctionMediator
ModuleJunctionMediator (Acme)
ModuleJunctionMediator (Foo)
To make our lives easier when it comes time to unload the module, the module caches the app’s pipe fitting it’s connected to. This allows the module to easily ‘cleanup’ (disconnect our fittings) should we want to unload the module. You may find a cleaner approach to this, feel free to post in comments - the ‘caching approach’ was simple and thus the road taken for the demo.
Understanding PureMVC Pipes
Written on 15 June 2008 by JoshuaDisclaimer: This a bit of a longer post!!
The pipes utility is newer to PureMVC and as such, I’ve seen questions on the blogosphere regarding it’s use.
The plumbing metaphor should help wrap you head around this utility and it’s use. Keep in mind that a pipe allows for one-way message flow.
So let’s take a look at how the utility can be used.
One great features of ‘Pipes’ is that they can use used on top of an existing app. That is, you’ll simply need to define a JunctionMediator at/for each integration point.
Let’s look at the simplest case, an application that loads and communicates with a module. We’ll assume that at some point you’ll want to use this same app to use multiple modules down the road. You’ll need to create a JunctionMediator for the application and a JunctionMediator for the module. We’ll dive into the details for those mediators but at a high level, that’s it - we simply define a ‘JunctionMediator’ for each ‘player.’
Here’s a simple diagram
Our JunctionMediator’s will be connected together with pipes. We’ll have one pipe that allows for application-to-module message flows and another pipe that allows for module-to-application flows.
On the receiving end of a pipe, we’ll want a pipe listener (you’ll have only one pipe listener for a given pipe). We’ll use pipe listeners to handle incoming pipe messages.
To send messages down a pipeline, we’ll normally use the Junction’s ’sendMessage’ function.
Back to our simple example, our app’s JunctionMediator would be responsible for creating the app’s pipe fittings, creating pipes to connect to those fittings to the module.
So the first thing our app’s JunctionMediator would do would be to create a new junction at creation.
public class ApplicationJunctionMediator extends JunctionMediator
{
public function ApplicationJunctionMediator()
{
super(NAME, new Junction());
}
Once this mediator is registered with our facade, we’d want to create the PipeFittings. We’ll use a TeeSplit for outgoing and TeeMerge for incoming. The TeeSplit will allow us to connect to multiple modules for outbound messages. The TeeMerge will allow multiple modules to send messages up to our main app. We’ll also want to add a pipe listener on our TeeMerge. This listener will allow us to handle the messages being sent up from the modules to the app.
override public function onRegister():void
{
junction.registerPipe( PipeAwareModule.APP_TO_MODULE_PIPE, Junction.OUTPUT, new TeeSplit() );
junction.registerPipe( PipeAwareModule.MODULE_TO_APP_PIPE, Junction.INPUT, new TeeMerge() );
junction.addPipeListener( PipeAwareModule.MODULE_TO_APP_PIPE, this, handlePipeMessage );
}
Our handlePipeMessage function is responsible for handling the messages coming up from our modules to our app.
function handlePipeMessage(message:IPipeMessage):void
Being a Mediator, we can define what application-level notifications we’re interested in and how to handle those notifications. That is, we’ll want to utilize listNotificationInterests() and handleNotification(note:INotification). We’ll use these to listen for notifications and turn desired notifications into messages to pass down our pipes.
For example, our Mortgage App would listens for request for loan notifications and turn those notifications into messages.
override public function handleNotification(note:INotification):void
{
switch( note.getName() )
{
case MortgageAppEventNames.REQUEST_FOR_LOAN:
var loanMessage:Message = new Message(MortgageAppEventNames.REQUEST_FOR_LOAN,null,note);
junction.sendMessage(PipeAwareModule.APP_TO_MODULE_PIPE,loanMessage);
break;
}
}
Our application JunctionMediator will also typically listen for a notification that a module has been loaded. Our app’s JunctionMediator will then create new pipes to connect the app’s junctionMediator to the modules junctionMediator. Something along the lines of…
override public function handleNotification(note:INotification):void
{
switch( note.getName() )
{
case MortgageAppEventNames.REQUEST_FOR_LOAN:
var loanMessage:Message = new Message(MortgageAppEventNames.REQUEST_FOR_LOAN,null,note);
junction.sendMessage(PipeAwareModule.APP_TO_MODULE_PIPE,loanMessage);
break;
case ModuleEvents.CONNECT_MODULE_JUNCTION:
var module:IPipeAwareModule = note.getBody() as IPipeAwareModule;
// Create the pipe
var moduleToApp:Pipe = new Pipe();
// Connect the pipe to our module
module.acceptOutputPipe(PipeAwareModule.MODULE_TO_APP_PIPE, moduleToApp);
// Connect the pipe to our app
var appIn:TeeMerge = junction.retrievePipe(PipeAwareModule.MODULE_TO_APP_PIPE) as TeeMerge;
appIn.connectInput(moduleToApp);
// Create the pipe
var appToModule:Pipe = new Pipe();
// Connect the pip to our module
module.acceptInputPipe(PipeAwareModule.APP_TO_MODULE_PIPE,appToModule);
// Connect the pipe to our app
var appOut:TeeSplit = junction.retrievePipe(PipeAwareModule.APP_TO_MODULE_PIPE) as TeeSplit;
appOut.connect(appToModule);
break;
// And let super handle the rest (ACCEPT_OUTPUT_PIPE, ACCEPT_INPUT_PIPE, SEND_TO_LOG)
default:
super.handleNotification(note);
}
}
Finally our application’s JunctionMediator will handle the incoming pipe messages.
override public function handlePipeMessage(message:IPipeMessage):void
{
// Handle our Module->Application integration
trace(message);
var note:INotification = message.getBody() as INotification;
switch(note.getName())
{
case MortgageAppEventNames.LOAN_QUOTE_READY:
sendNotification(note.getName(),note.getBody(),note.getType());
break;
default:
sendNotification(note.getName(),note.getBody(),note.getType());
break;
}
}
That covers the basic responsibilities for our app’s JunctionMediator.
Our module’s JunctionMediator would listen for messages coming in on the APP_TO_MODULE named pipe and send [outbound] messages on the MODULE_TO_APP pipe.
override public function handleNotification(note:INotification):void
{
// Handle our Module->Application integration
switch( note.getName() )
{
case ModuleFacade.QUOTE_GENERATED:
// convert our *local* notification into the application format
var quoteMessage:Message = new Message(MortgageAppEventNames.LOAN_QUOTE_READY,null,
new Notification(MortgageAppEventNames.LOAN_QUOTE_READY,note.getBody(),note.getType()));
junction.sendMessage(PipeAwareModule.MODULE_TO_APP_PIPE,quoteMessage);
break;
}
}
override public function handlePipeMessage( message:IPipeMessage ):void
{
// Handle our Application->Module integration
var note:INotification = message.getBody() as INotification;
switch(note.getName())
{
case MortgageAppEventNames.REQUEST_FOR_LOAN:
sendNotification(ModuleFacade.QUOTE_REQUESTED,note.getBody(),note.getType());
break;
}
}
If the app was to load another module our diagram would become…
If your still have questions - just ask
Loaded Module Dimensions - Width / Height
Written on 13 June 2008 by JoshuaRan across a problem regarding the display size of dynamically loaded modules today. The module was a subclass of ModuleLoader. The module would size to the minWidth / minHeight I had specified but would ignore width=”100%” for height=”100%”.
This Adobe Tech note states that your module should use ‘percentWidth’ and ‘percentHeight.’ I set that for the module and still no luck (probably because I subclassed ModuleLoader not Module for the time being).
What did work was to set the percentWidth / percentHeight in actionscript before I call addChild().
module.percentHeight = 100;
module.percentWidth = 100;
this.addChild(module);
Pipe Architecture
Written on 13 June 2008 by JoshuaHere’s a working architecture for modular applications utilizing PureMVC pipes.
This allows you to have modules that load modules that load modules, etc. The modules communicate to each other via Pipes.
The sample diagram illustrates a parent, child, grandchild relationship (An app that loads a module that loads module). You can of course, have multiple siblings.
PureMVC Pipes
Written on 12 June 2008 by JoshuaI had a chance to work with Cliff Hall’s PureMVC ‘Pipes’ utility this week. Highly recommended.
If your interested in utilizing modules in your PureMVC projects, you owe it to yourself to take a look at the Pipes utility.
What’s needed to integrate a module?
The requirements are very light. You module should:
Implement IPipeAware
Create a JunctionMediator.
Thats it.
I took some time and refactored the Mortgage app to use the Pipes utility.
I ran into a small bump after unloading widgets. If I unloaded a widget and then clicked “Quotes”, I still received a loan quote from what should have been an unloaded module. I ended up subclassing the ‘TeeSplit’ class to allow disconnecting a single known IPipeFitting. This allowed me to ‘cleanup’ the dynamic modules properly.
That aside, the utility was very easy to work with - the plumbing metaphors really make things clear.
I found the utility to be quite flexible as well. I just wrapped up working on some utility classes that allow modules to load modules that load modules etc. Getting this to work with direct core to core communications was at best ‘messy.’ Using the pipes made this very clean and simple.
PureMVC + Lazily [late] Instantiated Components
Written on 6 June 2008 by JoshuaOne small caveat when working with PureMVC - If your [view] component is defined at design time, but not created at application startup you’ll need to defer the
facade.registerMediator( )
This might happen, for example, when your component resides in a viewstack.
A simple work around is to dispatch an event (make sure it bubbles) on the component’s creationCompelete.
creationComplete="dispatchEvent(new Event(CommonEvents.COMPONENT_INITIALIZED,true))"
In the ‘application level’ mediator, create an event listener for this event
viewComponent.addEventListener(
CommonEvents.COMPONENT_INITIALIZED,onComponentReady,false,0,true);
When the event is picked up you’ll have to determine which [lazy] component is ready
public function onComponentReady(event:Event):void
{
var comp:UIComponent = event.target as UIComponent;
switch(comp.id)
{
case "userSearch":
facade.registerMediator(new UserSearchMediator(comp));
break;
case "serviceRecord":
facade.registerMediator(new ServiceRecordMediator(comp));
break;
case "appToolbar":
facade.registerMediator(new AppToolbarMediator(comp));
break;
}
}
So, in short, we simply defer creating the component’s mediator until the view component is ready
Securing AMFPHP 1.9 via Authentication
Written on 3 June 2008 by JoshuaWith the loss of the methodTable in AMFPHP 1.9, comes a loss of the easily defined ‘roles.’
Background
Roles, for those of you who aren’t familiar, allow you to ‘protect’ who can invoke your AMFPHP services. For example, you probably wouldn’t want the following function accessible to everyone
public function SetEmployeeSalary($amount)
Users are ‘authenticated’ in AMFPHP via a call to
Authenticate::login($username,$roles);
Where $roles is a comma delimited set of roles for the user. If you open up \core\shared\util\Authenticate.php you’ll find the login method
function login($name, $roles) {
if(!session_id())
{
session_start();
}
$_SESSION['amfphp_username'] = $name;
$_SESSION['amfphp_roles'] = $roles;
}
Authentication in AMFPHP 1.9
To utilize authentication in 1.9, create a function with the following signature in your service (class).
public function beforeFilter($function_called)
A quick peek in /core/shared/app/BasicActions.php and you’ll see that, should your service (class) define this function, AMFPHP will call it before invoking your function. If beforeFilter returns true, the function is invoked, otherwise a security error is thrown.
Here’s the simple approach I’ve taken..
public function beforeFilter($function_called)
{
$memberName = $function_called."Roles";
return (@$this->$memberName) ? Authenticate::isUserInRole($this->$memberName) : true;
}
So to secure any function, I simply define a member variable with the roles required.
var $SetEmployeeSalaryRoles = "admin,hr";
public function SetEmployeeSalary($amount)
My beforeFilter function looks to see if functionNameRoles exists, if it does, than the user must have a role found in functionNameRoles. If functionNameRoles does not exist, no authentication is required.
Two must haves for those ‘rigorous’ developers out there.
Written on 2 June 2008 by JoshuaI’ve come across two [free] tools I find indispensable when working under the Windows platform.
Task arrange
Task arrange allows you to change up, on the fly, the order of programs listed on the taskbar.
Aqua Dock
I’ve moved all of my desktop icons off my desktop and onto the dock. No need to worry about my icons being shuffled around after hooking up to a digital projector for presentations
AS3 PureMVC Dynamic Modules
Written on 24 May 2008 by JoshuaOkay, I’ve had some questions on refactoring my PureMVC dynamic modules classes to support AS3 projects (i.e. no flex).
I’ve posted a sample app that does just that.
I threw this together off the cuff, so don’t expect too much
The app (10K) simply loads 6 modules dynamically, 3 “RedTint” modules and 3 “GreenTint” modules (4k each). The app sends a notification every second containing a random color. The loaded modules pick up on this notification and display the color - each with their corresponding tint.
Keep a close eye on Cliff’s Pipe utility as these classes may soon be obsolete Until that time, I hope you might find this useful - if you do, drop me a line and let me know.
I’ve got some time between projects if anyone is looking for some RIA development…
Adobe AIR on MAC
Written on 23 May 2008 by JoshuaWhile wrapping up a project for a client, I ran into a problem that one of my AIR apps didn’t work on the client’s Mac. This particular project consisted of a ’suite’ of applications, two AIR apps and one Flex app. The other two apps in the suite worked great, however the problematic AIR app just displayed a gray screen. In case anyone else runs into this - it turned out to be due to the omission of the ‘height’ parameter in the WindowedApplication tag.
