Seeing connections

There are patterns within and among patterns for many of the original GoF design patterns. For example, at first look, State and Strategy look very similar. The UML diagrams used to describe them in the book are almost identical. Part of the difference comes from the ways in which the patterns are applied but another key is to understand Joshua Kerievsky's caution that the UML is one implementation of the pattern. The UML is not the pattern and it is not the only way to implement the pattern. Concentrating on the UML makes different patterns seem similar and sometimes hides the underlying similarity among patterns.

A striking example is described in the latest column from Robert C. Martin's Principles, Patterns, and Practices series: The Factory Pattern. In it he shows that "Abstract Factory is just Strategy used for creating objects." He then reaches back to his last column that showed the relationships between Strategy and Template Method and concludes that Factory Method is the pattern that uses Template Method instead of Strategy.

In Also in Java Today , " The FilteredRowSet lets one narrow down the number of rows in a disconnected object based on filtering logic you provide without requiring an ongoing connection to your database." In Kulvir Singh Bogal's DevX article Master the FilteredRowSet Interface for Disconnected Data Retrieval he shows you how to provide your filtering criterion based on the javax.sql.rowset.Predicate interface and how to apply the filter to some real data.

Aspect-Oriented Programming (AOP) and attributes have their own typical examples - you often see AOP introduced for logging and attributes are great for generating code. But what happens when the two are combined? Bill Burke explains "Together, they make a new powerful combination that gives framework developers a more expressive way of providing their APIs." In Aspect-Oriented Annotations, he shows how to use attributes to indicate the point-cuts for AOP, in effect extending the Java syntax by providing, for example, a pseudo-keyword that indicates a method is to be fired off in its own Thread.

Eduardo Pelegri-Llopart asks if you Want to help create JAX-WSA in today's Weblogs . " Arun is looking for a couple of good members for the JAX-WSA expert group. Specially from smaller companies and expert individuals."

Srikanth Shenoy asks " When was the last time you manually copied data from a Struts Form into a Value Object?" His post Copying data from Struts ActionForm to ValueObject: Easing the pain explains " Copying data from one object to another is typically achieved with Commons BeanUtils. However if the source and target object have different structure and different attribute names, BeanUtils cannot do much. That's where you will fnd OTOM framework helpful. OTOM lets you graphically map one class to another in a Swing UI and create napping metadata. The mapping source code can be then generated using an Ant task at build time. Sounds useful..? Take a look - http://otom.dev.java.net "

John Reynolds things about The Same Big Things " The techno-clairvoyants have been strangely quiet of late... so I am left on my own to predict what 'The Next Big Thing' is going to be. I think that one 'Big Thing' will be to put the "P" in COBOL: a Common Business Process Oriented Language."

In Projects and Communities, the JavaDesktop community links to the transcript from the recent Java Live Chat with Chet Haase and Scott Violet which included discussions on "Longhorn, SwingWorker as official API, acceleration work in progress, and grey rectangles".

The Patterns community is featuring a pointer to the Refactoring: Introduce Adapter. The advantage is it "limits the possible inputs to the actual object to what clients would normally need so developers do not have to know which part to get from the data."

In today's Forums, finzic asks "Does anyone here in the Java Development arena have some suggestions about cheap (if not free!) Java Reporting Engines? I currently use a reporting engine that gives me poor control over embedded pictures and has poor report composition tools, and I need to find a better tool."

Invalidname has a bit of a File rant saying "java.io.File [has] "no way to get volume size", "no way to get free space on a volume", "no access to TYPE/CREA on Mac OS", "no access to mime type on BeOS", "no access to 'nix file permissions", "concept of unique paths is wrong on Mac OS (could have multiple root-level devices with same name)", "no frickin' copy() method", [..]"

In today's java.net News Headlines :

• AspectWerkz 2.0
• Java Caching System Now Apache Sub-Project
• jsXe 0.3pre15 - Java XML Editor
• SwiXAT 0.2.0 - Initial Release
• Mozilla Suite's Future in Question

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