Brad's Blog

May 4th

Arrived in San Francisco after a smooth flight, this flight is so quick from So Cal, you get a little reading in and before you know it you're on the ground again. Grabbed a shuttle to the hotel, Serrano Hotel, got my room and headed out for a little stroll to find some grub before I get an early start on Monday. Grabbed a tuna melt at TAD's which is a few blocks away. Never been, food wasn't bad and they seemed to have a big breakfast menu. Considerably cheaper than the Ponzu

which is running about 30.00 a meal (maybe I'll check it out before I leave). 

I must say, there is something about San Francisco, cool air hitting your face, homeless asking for money every corner, street musicians playing saxophone/guitar and what else they have, cable cars going by, people on the move, that's really enjoyable. Every time I come here, there is some real character to this place that is like no other place I've been. Quite nice to walk the streets, to see the hustle and bussel moving through the streets being apart of it for a week is a nice change. The weather is cool jacket weather that feels great from the heat of the south lately.

After my walk, I headed back to the hotel, prepared myself for the day to come, set the alarm and hit the hay.

May 5th - Cinco de Mayo

Got up at the break of dawn, 6:10 am (that's early for me), headed over to Moscone North, grabbed my registration and went to the lower level to pick up my materials for the conference. It's been since 2004 since I've visited Moscone and JavaOne, it looks similar to previous years, it always looked good and ready to deliver. This year is no exception. I guess I was so anxious to get over to the center and get my learn on that I had about two hours before my first Session, Developing Enterprise Applications with the Spring Framework, with two backpacks in tow I headed back to the hotel to drop some of this mess off.

Headed back, I grab a coffee and a piece of Banana Nut Bread from Starbucks, then it's over to the Intercontinental Hotel (Nice hotel) for the session.

Spring Framework by Chris Richardson

Since I've used Spring Framework with uPortal and some of the other projects at work, the first half of this session was simply a reminder of configuration possibilities and reasons why to use the framework, like the removal of DRY (Don't Repeat Yourself) code, easy testing with Mock Objects (Chris used JMock 2), removal of dependancies. Chris also covered xml configuration and annotation based configuration, even covered Java Config for configuring Spring. I guess I must have skipped the Bean Scopes somewhere along the way because Chris' explanation of them eye opening, kind of woke me up (hey you know you can do this?)

Bean Scopes

Singleton

• The default and most common
• Only create a single instance
• Use for stateless beans

Prototype

• Create a new instance each time you need one
• When its injected or requested by getBean()
• Use for stateful beans

 
Request and Session

• Use in web applications for request/session-specfic state
• The bean lives for the lifetime of request or session
• Referencing beans are injected with a proxy

Next, he
covered Transactional Services in Spring. Transactional services offered by
Spring simplify user’s code by removing the repeated code. Spring allows you to
write metadata to create transactional POJOs. Via the help of Aspect Oriented
Programming (AOP) and Spring your code can be greatly reduced. Before I get
into the Spring AOP I’d like to cover a few AOP basics.

AOP Basics

Joinpoint

● Well-defined point during the execution of your application

● You can insert additional logic at Joinpoint's

● Examples of Jointpoint's

– Method invocation

– Class initialization

– Object initialization

Advice

● The code that is executed at a particular joinpoint

● Types of Advice

– before advice, which excutes before joinpoint

– after advice, which executes after joinpoint

– around advice, which executes around joinpoint

 

Pointcuts

● A collection of joinpoints that you use to define when advice
should be executed

● By creating pointcuts, you gain fine-grained control over how
you apply advice to the components

● Example

– A typical joinpoint is a method invocation.

– A typical pointcut is a collection of all method invocations in
a particular class

● Pointcuts can be composed in complex relationships to further
constrain when advice is executed

Aspects

● An aspect is the combination of advice and pointcuts

 

 

For more on Spring AOP see
http://www.javapassion.com/j2ee/springaopbasics.pdf.

 

Spring wraps objects with
proxies that can execute extra advice before method invocation, after invoking
a method, or instead of a method. Transactions are managed through TransactionInterceptor.
This class manages transactions and intercepts method calls then delegates to
the PlatformTransactionManager.

 

By wrapping objects, your
components are unaware of the transactional code that is executed when your
object interact with other objects what are using Spring’s AOP Transaction
Management. Management is configured through an xml
configuration or via Spring Annotations. Check out <context:annotation-config/>
for
annotation
configuration.

Spring allows programmers to remove tightly coupled, duplicated and tangled code with code that is easier to maintain, test, and develop.

  Chris did a good job of explain how Spring can help. The AOP/Transaction management was a real eye opener and features that I don’t currently use. The dependency injection part of spring has been something I’ve been using for quite some time. I’m not going to cover every aspect of the session but I’ve tried to highlight some of the key points that Chris when over in the session. Additional projects that Chris is involved with are:

http://code.google.com/p/aop-ood

http://code.google.com/p/projecttrack

http://code.google.com/p/aridpojos

http://code.google.com/p/ormunit

http://code.google.com/p/umangite

http://code.google.com/p/cloudtools

 

Web 2.0 Leveraging the Project jMaki and Google Web Toolkits for
Rapid Website Development

 

jMaki

 

This session started with
Evan Troyka discussing jMaki. jMaki is
a wrapper for different ajax libraries like dojo and Yahoo ui. jMaki uses jsp
tags, JSF components, php libraries, and phobos implementations for different
deployments. A jMaki component consists of three different files, component.js,
component.htm, and a component.css. An optional file is the config.json. This
is a central location for configuration of javascript libraries, API keys, CSS
dependencies, jmaki Glue handler mappings, mapping extensions, and theme
information. jMaki glue lets you wire together jMaki widgets via a
publish/subscribe event model. This was interesting to see how you can use
different components from ajax libraries via one technology like JSF or JSP tags.
Some additional information on jMaki can be found at:

 

http://forums.java.net/jive/forum.jspa?forumID=96

http://weblogs.java.net/blog/carlavmott

http://weblogs.java.net/blog/gmurray71

http://weblogs.java.net/blog/arungupta

 

GWT

 

The real value (for me) in
this session was the second half where David Geary went over GWT Toolkit. I’ve messed with
this a little but I haven’t really dug into the project much. Wow was this
helpful to see the possibilities with GWT. GWT is a java library that allows
you to compile Swing like code into JavaScript. This eliminates the need to
test code for cross browser compatibility or learn JavaScript altogether. Some
of the features of GWT:

 

·        
Debug client-side UI in Java code

·        
Make remote method calls to a servlet

·        
Incorporate Javascript with native methods

·        
Use widgets and implement new ones

·        
Use the browser history mechanism

·        
Integration with JUnit

·        
Internationalization

 

More on GWT later. You can
also look at http://cooland usefulgwt.com.

I’ve been trying finish
this damn entry the last two days, there was just so much information at
JavaOne, it make it difficult to cover all that was there. To think I’m still
on Monday, Java University, before the conference session really started.

 

Really today was jammed with
material, each session was 3 hours long and we stopped after 8pm. I was toast,
tons of information and it's only the beginning. I really hope to finish the
blog but I'd like to get some sleep for tomorrow is another day of learning.

Really today was jammed with material, each session was 3 hours long and we stopped after 8pm. I was toast, tons of information and it's only the beginning. I really hope to finish the blog but I'd like to get some sleep for tomorrow is another day of learning.

JavaOne 2008

Without actually thinking anyone would read this, I've been trying to spend a little more time writing in my blog. But work and life in general seem to get in the way.

Good News is on the horizon! I'm about to close on a new home with my squeeze, Lisa, and I'm off to JavaOne this week. I know, can't get much better than that! It's been since 05, the last time I went to San Fran to visit Duke and the city by the bay, so I'm going to try to make the most of it. Major changes to Java and other languages based on the JVM have arrived so the goal is to check some of those languages out (Grails, JRuby). Also I want to get more information on JSR 296. I've started a development in that area and I'm curious to see what is going on with that. I will for sure check out some Spring session as it's moving to 2.5 release, so I'm sure there is valuable information there. As I'll need that because I've been messing with the new Spring Web Flow 2.0.0 RC1 release. I also have a session on jMaki, not to sure what to expect, but it should be interesting as I haven't been messing much with the Ajax stuff, so this seem like a good time to check it out of some hot clam chowder. Other notables are a session on JXTA which I haven't seen nor heard much from in years (I did my thesis using this technology). I'm quite interested to see if anything changed there (Wait as I'm getting the link, I see there is a new version 2.5 that has been released in November 07).

So as I prepare for my trip, I'm looking forward to all the information I can cram into my brain for the week and feel comfortable knowing that all the paperwork is in place for the new pad, for when I return, we can have a smooth transition from our current location to the new one. (Let's hope these damn gas prices give)

MAVEN DEPENDENCIES

Dependency scope is used to limit the transitivity of a depedency, and also
to affect the classpath used for various build tasks.

There are 5 scopes available:

• compile
  This is the default scope, used if none is specified.
  Compile dependencies are available in all classpaths of a project. Furthermore,
  those dependencies are propagated to dependent projects.
  
• provided
  This is much like compile , but indicates you
  expect the JDK or a container to provide the dependency at runtime. For example,
  when building a web application for the Java Enterprise Edition, you would set
  the dependency on the Servlet API and related Java EE APIs to scope
  provided because the web container provides those classes. This scope
  is only available on the compilation and test classpath, and is not transitive.
  
• runtime
  This scope indicates that the dependency is not required
  for compilation, but is for execution. It is in the runtime and test classpaths,
  but not the compile classpath.
  
• test
  This scope indicates that the dependency is not required for
  normal use of the application, and is only available for the test compilation
  and execution phases.
  
• system
  This scope is similar to provided except that you
  have to provide the JAR which contains it explicitly. The artifact is always
  available and is not looked up in a repository.
  
• import
  This scope is only used on a dependency of type
  pom in the <dependencyManagement> section. It indicates
  that the specified POM should be replaced with the dependencies in that POM's
  <dependencyManagement> section. Since they are replaced,
  dependencies with a scope of import do not actually participate in
  limiting the transitivity of a dependency.

For more

Ok after years of procrastination, I've finally broken down and gotten a new phone, but not just any phone, I got an iPhone. After hearing all the hype and the expense I've fought the urge the purchase a new phone for some time. My previous phone was the Treo 650. Now I guess this phone serviced its purpose, but the interface had issues and I could never really tell how many voice messages were in my inbox without calling. The internet of the phone, was pretty much unusable.

Now for the iPhone, this thing is cool. Really cool! I can tell when people call, leave voicemail, sms, and the internet with the 802.11b/g capability, forget it! This thing rocks! I didn't think one little device would be so much help and distraction all in one little package. I mean I really don't spend that much time away from the computer, and now with this little device, its really difficult to not take it to lunch and dinner and read what's up in the world wide web.

I'd really like to write some code for this thing, but I don't own a mac, but this thing may just cause me to breakdown an purchase yet another Apple product.

Random Note:

Luminis IV is built on top of uPortal 2.5.3.

ForFiles

Just a quick note to self, deleting Apache files older than 60 days:

forfiles /p f:\Apache\Apache\logs\ /s /m ssl.log /d -60 /c "cmd /c del @file"

Oh yeah! Blog more often!

Quick Notes for me:

Tidy.jar has dom implementations that must be removed. These class file conflict with the dom implementation that is in JDK 1.6. Quick fix to remove the org.w3c.dom class files from the tidy.jar.

xml-apis.jar must be removed as well for the same reason.

CAS Setup Information

Testing remember to generate a cert with name localhost.

http://www.ja-sig.org/wiki/display/UPM/01+CAS+Authentication+for+the+Impatient

SSL Issues

Proxy Validation Issues

March 21, 2007 – Day One
Session 1: Effective Aspect-Oriented Programming – Ron Bodkin

rbodkin@newaspects.com
http://www.eclipse.org/aspectj

Eclipse with AspectJ Plugin or Spring AOP or JBoss also have tools for eclipse as well.

Pointcut defines the join point where we want to call the aspect.

public aspect MeteringPolicy {

pointcut useTitle() :

execution(public void Song.play()) ||
execution(public void Song.showLyrics());

after() returning : useTitle() {
MeteringService.trackUse();

}

}

Terms: advice method (do the following thing), pointcut
ajc links the aspects to the java objects. You need to use ajc at some point to grab the pointcuts in the java code. However, Spring will use proxies that are called instead of requiring the use of ajc (aspects compiler) to modify the bytecode.

Used for tracing, monitoring, handling boiler plate code, used for understanding your system better.
Example:

call(* Remote+.*(..) throws RemoteException);

This example can be used to handle all the RemoteExceptions so the programmer doesn’t have to write the code to handle RemoteExceptions. This removes the boiler plate code of the try/catch in every call that throws a RemoteException.

Advice: Start small, only a few should write the aspects. Incremental adoption works best

Random Notes:
AspectJ 5 (latest, most flexible)
Spring AOP – handles a subset of the JAspects advices handles
JBoss AOP
Check out Glassbox for performance monitoring and problems. Uses load time weaving.

Session2: Crystal Clear: A Human Powered Methodology for Small Teams – Alistair Cockburn

Talk about agile coming out well or not well. What’s the difference?

Crystal Clear – Questions
Small teams hasn’t been working well…

Nothing written down
specs not clear
more changes than people can do
resource-starved project … req’ts /it infrastru /

Techniques for getting max benefit from limited resources
Guidelines to use agile
When Customer/sponsor

Successful projects where listening to the people (people-centric) and constantly modify the methodology.

Different people do different things. Can’t drive a methodology down someone’s throat. Different projects and people use different methods (pair programming, uml design, test driven development, etc). happy people ship, happy code! People like to be told what to do, so they won’t do it. Each person has to say what they are going to do.

Crystal’s purpose: Keep people from hurting each other, keeping each other informed
Crystal’s nature: A set of conventions that get updated

Six people or less. Give them a whiteboard, let them ship code, and you’re almost done.

Thinks of each project as a game.
Primary Goal: Deliver the project
Secondary Goal:

From the seven principles of methodology design
Face-to-face communication is the cheapest and fastest channel for exchanging information

Recommended Reading
The Goal (Paperback)
by Eliyahu M. Goldratt (Author), Jeff Cox (Author)

Frequent Delivery
Osmotic Communication – no private offices, communication is easy
Reflective Improvement – What are we doing, how are we doing it. How do we improve.

Personal Safety
Focus – don’t work on two or more projects
Easy Access to Expert Users
Technical Environment with (agile places this first, that’s ok)
Frequent integration
Automated testing
Config management

Critical technique in Crystal: Slide 20 Reflection Workshop. Discuss and determine what things you’re going to try. Try these are things you can control and do.

Sets projects based on color. Clear, Orange, Yellow, etc.

Session 3: An Overview of TR1 – Scott Meyers

smeyers@aristeia.com
http://www.aristeia.com

Technical Report 1 – Future standard of functionality to be in standard C++

Currently in the std::tr1 eventually maybe in the std namespace. You must have a TR1 conformant library for this to work.

New Functionality: C99 Compatibility

TR1 is a specification. This is an interface specification not an implementation. To understand the functionality in TR1: http://www.aristeia.com/EC3E/TR1_info.html

10 of the 14 libraries in TR1 are modeled on Boost libraries. Boost will bring its libraries into conformance with TR1.

gcc 4.0 – has some of the TR1. To get it, you can use Boost library, it has 11 of the 14. You can also look at Dinkumware.

Smart pointers declared in the header <memory>. Check out auto_ptr and shared_ptr. “this” is a raw pointer. Be careful when returning shared pointers to yourself.

Operators: static_pointer_cast, dynamic_pointer_cast, const_pointer_cast
Relational: ==, !=, <

Output: <<

auto_ptr solves the problem of exclusive ownship. shared_ptr solves the problem of shared ownship. auto_ptr always deletes its resource.

tr1::weak_ptrs can’t keep resources alive. Solve the problem of dangling pointers and cyclic references.

TR1 tells you nothing about where these features are thread safe.

HashTables

Regular Expressions
declared <regex>

Pete Becker’s Book on TR1. Slide page 54.

Session4: Puzzlers

Review the slides…

Examine - Autoboxing, varargs, generics

March 23, 2007

Session1: What’s coming in Java6 – Jason Hunter

StaX – pull parse, doesn’t store the whole document in memory, good good.

Annotations
Thrid Party @Nullable, @notNull – IntelliJ
@Test, @Before, @After in JUnit 4
@Immutable, @ThreadSafe, @NotThreadSafe, @GuardedBy from Java Concurrency in Practice

Java 5 – apt (annotation processor tool)
Java 6 – (standardized) java –processor

Core HTTP Server
Mini-Servlets, in com.sun.net.httpserver. Designed to support JMX and JAX-RPC. Only used for their own purposes.

New Deque = Double Ended Queue
acts like a Queue + Stack
Navigable Sets and Maps, let’s you get near missed items. I’m looking for this, if its not there, give me the one right above it or the one right below it.

Randomized Skip Lists - http://en.wekepedia.org/wiki/Skip_list
A linked list capable of large forward jumps

Removing feature’s in Java 6
Aimed at reducing the Java Runtime jar. The first thing to remove is javax.sound.midi, it has a target.

Java 7
Just thinking about stuff right now.
JAM to JARS. Java Modules proposed in JSR 277
Use the metadata to discover, load, and check module
Also superpackages, package families, which has special rights to classes in the superpackage

Dynamic Languages – new invokedynmaic bytecode
JSR 292 would let you invoke methods in the absensce of static type information

NIO 2 – JSR 203
A new filesystem API
Asynchronous filesystem calls
Better tie socket channels and sockets
(Fuse) - http://fuse.sourceforge.net/

Javadoc Update
More easily identify factory methods

Non-API features
Putting XML in as a standard data type
Strings in switch statements
Comparisons for enums
Closures?

http://java.sun.com/avase/6/docs/api
http://planetjdk.org
get slides @ jhunter@marklogic.com

Session2: Extreme Web Caching – Jason Hunter

javap -public -classpath jsse.jar java.lang.Class
Determines the public interface
Based on “HTTP Caching & Cache-Busting for Content Publishers by Michael Radwin

Client
GET /index.html HTTP/1.1
Host: www.server.com

Server
HTTP/1.1 200 OK
Date: …
Last-Modified: …
Content-Length: 2750 (Good for keep alive, this helps the client know when it’s the client’s turn to talk again)
Connection: close
Content-Type: text/html

<html><head><title>
…

Side note: JSPs buffer 8K by default
expires tag means the jpg or whatever is still go until that date. If-Modified-Since revalidates that the content hasn’t changed. If the content hasn’t been modified the server returns status code 304, not-modified-since, but doesn’t return the content the user requested.

1. Use “Cache-Control: private” for personalized content

Issue with cookies, sending a cookie say from jane back to john. So you should use Cache-Control header. Cache-Control: private
Disallows shared caching, allows private (browser)

Cache-Control: public
Explicitly allows shared caching

2. Implement “Images Never Expire” policy

Dictate that images (icons, logos) once published never change

Set Expires header 10 years in the future

Check – http://use.perl.org/~geoff/journal/22049

3. Cookie-free TLD for Static

Use a separate domain for static content

A domain without cookies

www.server.com for html

static.server.net for images, PDFs, etc

4. Apache Defaults for CSS/JS

Rely on If-Modified-Since request header
No special configuration needed

How can a server know when servlet content changes?

The .class timestamp is meaningless

Help the ser with getLastModified()

public long getLastModified(HttpServletRequest req) {

Return datamodified.getTime();

}

Called before doGet(), possibly avoiding doGet()

5. Random URL strings

Add javascript to create random url

Point all the ad servers to localhost 127.0.0.1, this removes all the adds when browsinghttp://www.everythingisnt.com/hosts.html

http://www.mnot.net/cacheability/http://www.mnot.net/cache_docs/

http://www.radwin.org – he’s blog

Session3: Java Persistence API Overview – Cay Horstmann

San Jose State University
Influenced by Hibernate, Oracle TopLink, JDO
Annotation the fields in the class, not the getter and setter.

There are five requirements for an Entity
Annotated with @Entity
primary key
no-arg constructor

Persistence context = set of managed entities
Entity manager = object that manages persistence context (find, persist, createQuery, …)

Need the persistence.xml file.

Can’ persist inner classes and final classes

With eclipse wait for Dali and WTP.

Address issues of refactoring the objects. What happens if we change the foreign key relationship or we modify the way that relationship between entities are modified.

What happens with the cache? If we get a result from a query and then modify the table so we have a new entity. If I query again the cache returns the original result set before the insert. How do we get around this?

Away around naming objects like “User” this is a sql reserved word. However, Hibernate has a method of getting around this does JPA.

Java Persistence Query Language (JPQL)

Lazy Fetching
Fetching is eager by default for @OneToOne, @ManyToOne.

To use an EJB container or not? Use annotations to get EJBs and a handle on the EntityManager.

Session4: What’s New in XML in Java 5 and 6 – Elliotte Rusty Harold

JAXP
DOM 3
Java XPath API
Java Validation API
Java XML Digital Signature API
StAX

Java 5 added DOM Level 3 support
Remember, getTextContent() and setTextContent(String textContent) cuts dozens of lines out of programs.

User Data – a user-defined callback class that is invoked when a node is cloned, imported, etc.

Bootstrapping
DOM2 has no implementation-independent means to create a new Document object

DOMImplementation impl = DOMImplementationImpl.getDOMImplemenation();
Document fibonacci = impl.createDocument(…);

To read a document, must import

org.w3c.dom.ls.*;
org.w3c.dom.bootstrap.*;

Checkout LSParserFilter, org.w3c.dom.ls, for removing parts of the document when reading.

Writing LSSerializer serializer = implls.createLSSerializer();

LSOutput output = implls.createLSOutput();
…blah… blah

XPath
Query without detailed DOM navigation
eg. //book[author=”Neal Stephenson”]/title”
javax.xml.xpath package

Java Validation API
package javax.xml.validation
JDK bundles W3C schema support

http://www.cafeconleche.org/slides/sd2007west/java5xml/

BOF – Interviewing in Silicon Valley

http://www.techsmith.com
htdye@linkedin.com

paultima.blogspot.com

Interesting bit of information about interviewing for jobs in Silicon Valley, from Google perspective. Discussion included a log of emphasis on algorithms and Big O runtime for algorithms. How would you sort a collection of A, for example, why? Advice was to focus on some open source projects that are interesting. This helps when potential employers look at your resume they see that you’re interested in the community and making contributions to projects.

March 23, 2007
Session1: Everything New in ASP.NET 2.0 - Stanfield

This session was a complete waste of time. The speaker was fumbling around, finished early and started his next presentation on AJAX. In addition, the presentation is available online from Microsoft, so the session was completely unhelpful.

Session2: Using Visual C++ To Light Up on Windows Vista – Nikola Dubar

Microsoft is trying to make development on Vista easier for C++ developers. Includes WCF, and WPF. The demonstration utilizes Visual C++ Orcas. Second part of the talk will be improvements to MFC. Check the article, Top 10 Ways To Light Up.

Orcas is coming out pretty soon.

User Access Control
Reliability and manageability
Restart Manager – saves the application’s state, shuts the app down, updates the application code and restarts the application.

Application Recovery and Restart – register callback functions, if the app dies this function is called to restart the application.

Function Discovery – enables apps to discover and manage lists of devices or objects sorted by functionality or class. Available before but it is more organized now, a standardize method for retrieving this information.

Cancelable I/O –

Customer Feedback Loop

Windows Quality Online Service, register with ms and get your app dumps when they crash. The apis provide ability to customize reports for your dumps. Check this out!

Windows Vista style guidelines

New Common Item Dialogs
Windows Vista Wizard Framework – PSH_AEROWIZARD
Checkout comctl32.dll

WPF – Rich library of controls – core component of .NET 3.0
No native code alternative
WPF, WCF, XPF – is only available in managed code
MFC part is all native

Organize and Search
All mechanisms are exposed via COM interfaces

WCF – Windows Communication Foundation
Helps with evolving client app into service oriented applications
Single programming model
Part of .Net Framework
No native code alternative

Mix mode allows you to use native C++ and call the .NET framework for features that use .NET features through C++ CLI.

Three modes
–clr (native and managed)
-clrpure (all managed code)
-clr (verifiable code)

RSS library

Document data
XML-based document packaging
XPS

Additional libraries for Mobile Devices
Network Awareness APIs
Sync Center
Power Management
Window SlideShow

10 new features in Vista only 3 are managed code the others are native code

VC++ Orcas
UAC-ready
Base Address Randomization – prevents hacker for getting address of dll. Hacker has to guess where dlls are loaded.
Data Execution Protection doesn’t allow buffer overflow

JPA – possible app rss reader that persists content
Or java accessing the .net apis for rss feeds etc

Session4: How to Build a Scalable Multiplexed Serer With NIO – Ron Hitchens

ron.hitchens@marklogic.com
ron@ronsoft.com
http://javanio.info

How to use NIO to build a server. Lower level i/o that is more sufficient for io than the java.io package. Gives access to some of the lower features that the OS has for I/O.

Three ways for multiplexing in a server.
Poll each socket – not very good cause we have to check each socket for a request. If there’s one there process it. This could starve other processes

Thread-per-socket – this is how java worked before. Overhead of managing many threads.

Readiness selection (NIO)selects the sockets that are ready, requires OS and JAVA VM support

The Reactor Pattern – Google for Douglas Schmidt*

http://www.cs.wustl.edu/~schmidt/patterns-ace.html

From the UML PatternDemultiplexer – knows which sockets are ready. This is the object that answers that question.
Event on a handle is some data has arrived

NOTE: buffer bytes and reconstitute the structure. Structured messages will be fragmented across the network.

Handler can’t write directly to the socket. This is by design it should only read and write to queues. Handler checks the queue to see if it do something with data. If there isn’t enough data the handler replies back to the Dispatcher, I don’t have enough data. Once all the data is there, the handler will do its thing with it.

Old model is thread per socket, bad. This new model is one thread per message.

NIO Reactor UML – blue objects are part of the jdk

O’Reilly – Ray Lischner’s C++ in a Nutshell

Now I have a good portion of the Gradebook app working in uPortal. Next I need to add the export in Excel and CSV formats to the instructor view, but before I got that far, I'm going to  add data from a live course. I mean the course information with the roster. The student view needs to be tested and examined before I can do anything else. Once I have the course and students loaded I'll return to export features, then I should be ready for demo day... Just wanted to write a quick note to myself, so I remember where I'm at on this. It took me all week to get to work on this, so I didn't want to forget my train of thought.

If I get the chance, I'd like to start working on my course material for my C++ course. Well I better find some way to wind down so that I can start another day tomorrow.

Now that I have the application (Sakai Gradebook) working as a portlet, I had to modify a few more things that the portlet framework didn't like.

1) I was receiving Portlet Exceptions on resources. assignmentDetails.jsp and courseGradeDetails.jsp were receiving exceptions when trying to retrieve the dhtmlpopup.css and the dhtmlphpup.js. The jsps use relative links to reference these files. I had to add the portlet context to the references to stop the exception from being thrown.

org.apache.pluto.core.impl.PortletResponseImpl.encodeURL() checks for absolute urls. If the resource is reference via a relative url, a PortletException is thrown.

2) Beans defined in the ui project are defined with request scope. These beans had to be modified to use session scope. Since the request is split in an action request and a render request, when the jsps are being rendered, there aren't any request variables in scope. This is solved by changing the bean scope to session and using my RoleListener to handle removing the bean upon new requests. Example, when assignment details are requested for each homework assignment, upon the initial request a session bean is created say for homework #1. Now if we make a new request to view details of homework #2, the session bean exists from the initial request and homework #1 is displayed again. Thus the session bean needs to be removed to create a new bean with the data pertaining to homework #2. Again this works fine if we're using the application as a standalone application, but since the app has been pushed into a portlet framework, uportal, the requests don't work as designed.

3) The popup for gradebook logs doesn't show the close icon due to it being specified as a relative link. I've changed the the following line:

closeIconUrl="dhtmlpopup/dhtmlPopClose.gif"

to

closeIconUrl="${pageContext.request.contextPath}dhtmlpopup/dhtmlPopClose.gif"

in the gradingEventLogs.jspf file. I also modified the tag library descriptor, gb-jsp.tld, changing the rtexprvalue to true so that the attribute "closeIconUrl" accepts and evaluates the ${pageContext.request.contextPath} expression.

<attribute>
<name>closeIconUrl</name>
<required>false</required>
<rtexprvalue>true</rtexprvalue></attribute>

Now the eventLogs popup shows correctly in the portal. One minor issue was that the popup was showing up lower than I liked so I removed the dhtmlGetPageYOffset() from the dhtmlPopupShow() function so that it displays the popup where the log image is clicked on (this is located in the dhtmlPopup.js).

4) **** Is another issue with the portlet getting the proper context for tags in the myfaces library. In the addAssignment.jsp, it uses the inputCalendar component. When this component is loaded it initialize the calendar. However, the component needs popcalendar_init.js and the popcalendar.js to initialize the calendar component. I assume that the issue is due to the application being in the portal context while trying to get the js files from that context and not the portlet context. I'll have to look into this later. However, a quick fix is to add the two js files to the js directory in the ui package in the Gradebook, then add references to the to files in the assignmentEditing.jspf file after the description text in the <h:panelGroup/> tag.

<f:verbatim><script src="${pageContext.request.contextPath}/js/popcalendar_init.js" type="text/javascript"></script><script src="${pageContext.request.contextPath}/js/popcalendar.js" type="text/javascript"></script></f:verbatim>