THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Why
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choose
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iPOJO?
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The
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OSGi
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Service
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Platform
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provides
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an
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excellent
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foundation
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for
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building
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dynamically
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extensible
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Java-based
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applications.
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However,
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such
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power
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and
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flexibility
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does
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not
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come
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without
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cost.
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In
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addition
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to
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new
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APIs
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and
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packaging
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formats,
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OSGi
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developers
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must
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shift
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their
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thinking
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to
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be
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able
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to
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design
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highly
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dynamic
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applications.
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Early
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efforts,
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such
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as
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the
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Service
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Binder
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and
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Service
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Tracker,
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attempted
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to
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alleviate
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some
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of
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these
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issues,
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as
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well
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as
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more
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recent
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efforts,
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such
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as
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Declarative
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Services
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and
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Spring
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Dynamic
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Modules.
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iPOJO
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is
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another
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such
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effort
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in
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this
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area.
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It
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is
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a
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service-oriented
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component
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model
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created
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specifically
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for
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the
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OSGi
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Service
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Platform.
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The
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purpose
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behind
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iPOJO
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is
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twofold.
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The
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first
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goal
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is
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to
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simplify
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OSGi
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development
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to
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the
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bare
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necessities.
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This
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means
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that
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providing
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services,
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using
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services,
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and
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dealing
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with
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dynamism
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should
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require
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as
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little
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effort
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as
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possible
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from
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the
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developer.
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The
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second
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goal
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is
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to
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push
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beyond
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support
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for
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basic
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OSGi
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mechanisms
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and
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try
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to
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more
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seamlessly
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incorporate
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advanced
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features,
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including
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component
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configuration,
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synchronization,
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and
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composition.
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This
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page
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summaries
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the
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key
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point
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of
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iPOJO.
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Simplicity
Trying to create an OSGi-based
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application
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with
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services
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is
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challenging.
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The
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OSGi
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API
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is
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complex
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and
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a
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lot
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of
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knowledge
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about
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internal
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mechanisms
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has
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to
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be
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known
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to
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avoid
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synchronization
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issues.
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iPOJO
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provides
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a
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very
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simple
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development
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model;
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let's
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look:
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}
@Component
@Provides
public class MyServiceImplementation implements MyService {
//....
}
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{code} \\ {code:java|Requiring a service} @Component public class MyServiceConsumer { @Requires private MyService myservice; // Just use your required service as any regular field ! } {code} |
Isn't
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that
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easy?
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Providing
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and
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requiring
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OSGi
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services
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have
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never
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been
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so
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simple.
Power
Supporting OSGi services is not the only feature of iPOJO. iPOJO provides many other features that to simplify developing sophisticated applications. For example, iPOJO supports configuring components with Configuration Admin, sending/receiving events with the Event Admin, remote configuration with JMX, and more.
Flexibility
Is iPOJO missing a feature you need? No problem. iPOJO provides an extensibility mechanism that allows you to mange other (custom) requirements. You can easily adapt iPOJO for your own needs. Creating an extension does not require modifications to the core, you only need to implement a custom handler that will be plugged on your instance. Your handlers can also use any of the other iPOJO features.
Portability
iPOJO works on any R4.1 OSGi implementation. It also works on many Java virtual machines such as Oracle JRockit, JamVM, Dalvik (Android), and Mika. iPOJO only requires a J2ME Foundation 1.1 virtual machine. So, iPOJO can be embedded inside mobile phone applications or inside your washing machine.
Performance
Being powerful is great, but what about footprint and performances? iPOJO is small and was designed to stay small. The core size of iPOJO is approximately 205k (compared to 816k for Guice-Peaberry and 2112k for the minimal Spring-DM configuration). In addition to the core, you only deploy the features you require. For example, if you need proxy injection, just deploy the temporal dependency bundle (less than 70Kb).
The run-time overhead of iPOJO is also small. On the Peaberry benchmark, iPOJO has very good performance:
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h2. Power Supporting OSGi services is not the only feature of iPOJO. iPOJO provides many other features that to simplify developing sophisticated applications. For example, iPOJO supports configuring components with Configuration Admin, sending/receiving events with the Event Admin, remote configuration with JMX, and more. h2. Flexibility Is iPOJO missing a feature you need? No problem. iPOJO provides an extensibility mechanism that allows you to mange other (custom) requirements. You can easily adapt iPOJO for your own needs. Creating an extension does not require modifications to the core, you only need to implement a custom _handler_ that will be plugged on your instance. Your handlers can also use any of the other iPOJO features. h2. Portability iPOJO works on any R4.1 OSGi implementation. It also works on many Java virtual machines such as Oracle JRockit, JamVM, Dalvik (Android), and Mika. iPOJO only requires a *J2ME Foundation 1.1* virtual machine. So, iPOJO can be embedded inside mobile phone applications or inside your washing machine. h2. Performance Being powerful is great, but what about footprint and performances? iPOJO is small and was designed to stay small. The core size of iPOJO is approximately *205k* (compared to 816k for Guice-Peaberry and 2112k for the minimal Spring-DM configuration). In addition to the core, you only deploy the features you require. For example, if you need proxy injection, just deploy the temporal dependency bundle (less than 70Kb). The run-time overhead of iPOJO is also small. On the [Peaberry benchmark|http://code.google.com/p/peaberry/wiki/Benchmarks], iPOJO has very good performance: {div:class=shell} Guice-Peaberry: 276.00 ns/call {color:#ff0000}iPOJO Service Dependency: 118.00 ns/call{color} Spring-DM: 2384.00 ns/call {color:#ff0000}iPOJO Temporal Dependency: 159.00 ns/call{color} {color:#ff0000}iPOJO Temporal Dependency w/ proxy: 173.00 ns/call{color} {div} |
For
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French
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readers,
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you
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can
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find
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additional
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benchmarks
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in
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chapter
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10
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of
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...
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...
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...
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Development support
Developing OSGi applications can quickly become a nightmare, when things are working as expected. iPOJO helps you debug your application (and it often happen). For starters, you can debug iPOJO components as normal OSGi applications (stack traces and line number are not modified). But thanks to iPOJO's introspection mechanisms, you can also know the structure of your application (which instance uses which service...),
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so
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you
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easily
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understand
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why
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a
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service
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dependency
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is
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not
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fulfilled,
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the
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value
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of
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properties,
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etc.
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Design
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support
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iPOJO
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also
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provides
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an
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architecture
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description
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language
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to
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design
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applications
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in
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a
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flexible
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and
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hierarchic
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manner.
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Designed
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applications
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are
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expressed
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in
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terms
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of
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services
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and
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are
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natively
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dynamic,
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meaning
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they
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support
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implementation
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evolution
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and
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substitution.
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Moreover,
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iPOJO
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supports
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service
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isolation
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to
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get
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your
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own
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private
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service.
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Conclusion
For any questions or feedback, send an email on the users@felix.apache.org
...
mailing
...
list
...
(send
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a
...
...
to
...
users-subscribe@felix.apache.org
...
to
...
subscribe).
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