Archive for the 'Developer's Cave' Category

Login Security: Password Hashing Techniques

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In support of Cyber Security Awareness Month, this article is written as a tutorial on basic login security, including techniques to defend against potential vulnerabilities. I encourage anyone with a software security background to comment on this article. Although I have some years of software security experience, peer review is essential for building secure systems.

TIP: Any and all security techniques (including these) should be considered experimental until thoroughly reviewed by the security community.

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Static: The Dark Side of Design

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Students of software must be taught early the benefits of object oriented design, lest they succumb to the dark side of static programming. When designing a software component, the temptation can be to write globally accessible public static methods in lieu of instantiable objects. Even experienced developers must remain diligent to avoid being turned to this quicker, more seductive, approach. Read the rest of this entry »

Serialized Data Survivability

Developer's Cave, Potential RPG 1 Comment »

Serialized object data is inherently fragile. A change in one class effectively renders any serialized data that includes the class (even deep within the object graph) unusable. This article describes how I have (potentially) addressed this problem in my MMORPG platform. Read the rest of this entry »

Concealed Controller Pattern

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This article describes an interesting design pattern that I utilized in my Potential RPG code. The following describes the pattern in general and how I’ve used it in my code. Has anyone seen this pattern in the wild? Does it have any other common forms or names? Read the rest of this entry »

Software Versioning

Developer's Cave, Potential RPG 2 Comments »

I’m trying to settle on a sensible software versioning scheme for Potential RPG. The most familiar structure is X.Y.Z, which I’m calling Generation.Feature.Incremental.

The generation is the major version of the software. A feature release indicates the completion of a set of available features. Incremental releases may include bug fixes and enhancements, as well as new features that might not be fully integrated or ready for a feature release.

Incremental version numbers are treated as steps toward the next feature release. The test environment (including Alpha testing) should see all incremental releases. However, the production environment (when there is one) may skip some incremental releases, but should see all feature releases.

In practice, this versioning plan may be too linear. For example, a bug that affects the production environment may need to be fixed before any next release is ready. What is more, the latest incremental release may include features not ready for the production environment. Branching is the revision control mechanism that deals with this, which must be accounted for in the software development process and release management scheme. For Potential RPG, I will probably resort to a fourth patch level version, indicating something was fixed outside the mainline of development.

In addition to the software version number, I also include an edition (”Alpha3″), which is a marketing version name, the repository revision whence the product was built, and the build date/time.

Here’s a handy article on retrieving the Subversion revision from within your Ant build script. Anyone with further advice/insight into the exciting world of version management is encouraged to comment.

JPanel Stabilizer

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This article covers a handy bit of logic to stabilize Java/Swing components that otherwise have annoying grow/shrink behavior. The (perceived) problem occurs when a Java/Swing application uses layout managers that obey internal components’ desired sizes. The layout shifts to accommodate internal components as they grow/shrink, which can cause much distress to the end user (at least it does to me). Read the rest of this entry »

The Trouble with Interfaces

Developer's Cave 2 Comments »

Java interfaces are a wonderful thing; don’t get me wrong. However, many interface contracts make assumptions about how the implementation will behave. What is more, Java offers no way to programmatically enforce such an interface contract.

This article discusses a particular example of interface behavioral assumption and how to (partially) enforce the behavior programmatically. Read the rest of this entry »

To Enum or Not to Enum

Developer's Cave, Potential RPG 3 Comments »

Java’s enum feature offers a powerful language capability: compile-time type checking of constants. In addition, enum constants make code much easier to read and debug. However, an enum represents hard-coded values, requiring application recompilation/redeployment to alter.

This conflicts with the mantra of code design taught to me: “Abstraction, abstraction, abstraction.” That is, a piece of software should be as general-purpose as possible.

Take, for example, the Potential RPG game engine. I’ve designed it to abstractly support MMORPGs, allowing game-specific content to be defined in external data files. This often precludes defining enum constants where they would otherwise make good programmatic sense.

For example, my game supports a variety of shop types (weaponsmith, alchemist, healer, etc.). Currently, these are loaded from a definition file, rather than being hard-coded in the software. Adding a new shop type can be done without modifying the code… almost (read on).

What I’ve discovered is that new content still requires logic and GUI code to be written against it. Therefore, the game must be recompiled/redeployed anyway, so why not just simplify things and hard-code enum constants?

Ideally, I’d love to make the game engine 100% abstracted from content. For example, all content-related code should be isolated into dynamically loaded classes, referenced by the content definitions. While it’s just me at the keyboard, simplification seems in order. (Unless someone is looking to invest in such a game engine…)

In summary, depending on the requirements of your project, just use enum constants unless the level of effort is worth the design/implementation/maintenance overhead. (Hmmm … now I’m talking like a software project manager.)

JFreeChart for SLOC History

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While in grad school, I learned to use gnuplot to create line/bar charts. It works well for command-line scripted data processing, so long as you’re good at discerning arcane commands.

Looking for Java-based charting, I found JFreeChart. I’ve only spent a couple hours with it, but it looks to be an impressive library. It’s not simple, but appears to be well designed.

I hope to become more adept at JFreeChart. So far, I’ve only redeveloped my Potential RPG Source Lines of Code (SLOC) chart (originally processed by gnuplot):

Can anyone offer other Java-based charting library suggestions? Any opinions of JFreeChart? Read the rest of this entry »

Java “Locking assertion failure”

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This article describes a Java-related assertion failure apparently due to a recent video driver update in Debian (and Ubuntu). The assertion dumps a backtrace to the console, but the Potential RPG Alpha client appears to be otherwise unaffected.

The remainder of this article describes the problem and how to work around it. Read the rest of this entry »