BoxSpring (draft)

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BoxSpring(draft)

• Justin Edelson
• VP, Applications Platforms
• MTV Networks Digital

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What is BoxSpring

• A set of enhancements to the Spring Framework.

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Why Does BoxSpring Exist?

• Apply lessons learned from ATG Dynamo while
  enabling a migration strategy.
• Codify configuration methodology.
• Reduce lock contention issues associated with
  XML-based configuration (see Struts, Tiles, etc.)

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Core BoxSpring Enhancements

• Pathed Bean Factories
• Layered Configuration
• GLOBAL Beans
• JMX Exposure of Bean Factories
• Path-Aware MVC Support

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Pathed Bean Factories

• Out of the box, Spring bean factories are flat
  all beans within a factory share a common
  namespace.
• Various techniques have emerged, but these are ad
  hoc.
• Box Spring codifies a namespacing technique based
  on file system paths.
• The bean named /DataSources/readDataSource is
  defined in /DataSources/applicationContext.xml
• These files/directories can be in the classpath,
  the file system, really anywhere Spring Resources
  can work.
• Smaller XML files less lock contention and
  easier to read.

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Layered Bean Configuration

• In a typical application, some configuration
  properties are common between various deployment
  stages dev, qa, testing, production, etc.
• Default Spring configuration handling requires
  either recreating entire bean definitions per
  stage or the (awkward) use of property files.
• Box Spring supports adding new property
  definitions in a stage-specific configuration
  files.
• Special operators allow for addition or removal
  of items in collections.

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Paths and Layers in Action
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GLOBAL Beans

• GLOBAL beans are similar to Spring parent beans
  define a set of properties common across N number
  of beans.
• The main difference GLOBAL beans are automatic
  (and thus less error prone).
• Want to define a property for every bean in your
  application? Create a GLOBAL bean in the root
  context.

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JMX Exposure of Bean Factories

• Springs JMX support is focused on exposing
  individual beans for management.
• This is important, but doesnt address managing
  factories.
• Nor does it allow you to inspect bean definitions
  at runtime.
• And we wanted to apply the same path structure to
  JMX because lots of beans can lead to a messy
  JConsole.

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JMX Browse Bean Factories
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JMX View Bean Definition
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Path-Aware MVC Support

• Pretty simple
• /admin/users/list.html -gt controller named list
  in /admin/users
• Again all about lock contention
• Not always appropriate, so its easy to disable.

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BoxSpring-Enabled Libraries

• BoxSpring-Enabled libraries include default set
  of configuration files in META-INF/spring.
• This resource path is automatically scanned for
  configuration files when using BoxSpring webapp
  support classes.
• Gets rid of includes (and name conflicts).
• Layered configuration allows for defaults to be
  easily overridden.

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Box Spring Modules

• BoxSpring Modules are packages containing default
  BoxSpring configuration for 3rd party projects.
• First two
• Resteasy
• Atlassian Crowd
• More to come

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Box Spring Platform

• BoxSpring includes a BoxSpring-enabled library
  called BoxSpring Platform that includes
• A global Quartz scheduler
• Config to expose the application context via JMX
• Config to expose BoxSpring MVC support
• More to come