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Declaring component types

XML
<component
    classname="my.Implementation"
    name="my-type">
</component>
Annotations
@Component(name="my-type")
public class Implementation {
  // ...
}

Creating component instances

XML only
<instance component="my-type"/>
<instance component="my.Implementation"/>
<instance component="my-type" name="my-instance"/>
<instance component="my-type" name="my-instance">
    <property name="property1" value="value1"/>
</instance>
  • Instances can contains a configuration given under the key-value form. Properties can also by complex type.
  • How-to use iPOJO factories

Providing services

XML
<component classname="my.service.implementation" name="my-service-impl">
   <provides/>
</component>
<instance name="my-service-impl"/>
Annotations
@Component
@Provides
public class Implementation implements FooService {
   ...
}
  • Only instances provides really services, so don't forget to declare an instance.
  • Published service interfaces must be implemented by your component implementation
  • Providing OSGi services

Publishing service properties

XML
<component classname="my.service.implementation" name="my-service-impl">
  <provides>
	<property name="foo" field="m_foo" />
	<property name="bar" field="m_bar" mandatory="true" />
	<property name="baz" type="java.lang.String" /> <!-- Static property (do not change at runtime) -->
  </provides>
</component>
<instance name="my-service-impl"> <!-- The configuration has to inject value in unvalued mandatory properties -->
  <property name="bar" value="5"/>
  <property name="baz" value="my string"/>
<instance/>
Annotations
@Component
@Provides(specifications= {FooService.class, BarService.class})
public class ProvidesProperties implements FooService, BarService {
    
    @ServiceProperty(name = "foo")
    public int m_foo = 0;
    
    @ServiceProperty(name="bar", mandatory=true)
    public int m_bar;
    
// ...
}

Using services with field injection

XML
<component classname="my.consumer.Implementation">
    <requires field="fs" />
</component>
Annotations
@Component
public class Dependency {

    @Requires
    public FooService fs;
    
    //...
}

Using services with method injection

XML
<component classname="my.consumer.Implementation">
    <requires>
	<callback type="bind" method="bind" />
	<callback type="unbind" method="unbind" />
    </requires>	
</component>
Annotations
@Component
public class Dependency {

    @Unbind
    public synchronized void unbind(BazService bz) {
        //...
    }
    
    @Bind
    public synchronized void bind(BazService bz) {
        // ...
    }

  //...
}

Reacting to lifecycle state changes

Immediate components

  • A POJO object (implementation object) is created as soons as the instance becomes valid
  • Instances that don't provide services becomes automatically immediate
    XML
    <component classname="my.service.implementation" name="my-service-impl" immediate="true">
   <provides/>
</component>
    Annotations
    @Component(immediate=true)
@Provides
public class Implementation implements FooService {
   ...
}
  • Lifecycle Callback Handler

Lifecycle callbacks

XML
<component classname="my.implementation" name="my-impl">
    <callback transition="validate" method="start" />
    <callback transition="invalidate" method="stop" />
</component>
Annotations
@Component
public class Implementation {
    
    @Validate
    public void start() {
        
    }
    
    @Invalidate
    public void stop() {
        
    }
}

Declaring properties

XML
<component classname="my.Implementation" name="my-impl">
    <properties propagation="true" managedservice="MyPID">
        <property name="boo" method="setBoo" />
	<property field="m_bar" mandatory="true"/>
	<property field="m_foo" value="4"/>
    </properties>
</component>
<instance component="my-impl">
    <property name="boo" value="..."/>
    <property name="m_bar" value="..."/>
</instance>
<instance component="my-impl">
    <property name="boo" value="..."/>
    <property name="m_bar" value="..."/>
    <property name="managed.service.pid" value="AnotherPID"/>
</instance>
Annotations
@Component(managedservice="MyPID", propagation=true)
public class Implementation {
    
    @Property(name="boo")
    public void setBoo(int boo) {
        //...
    }
        
    @Property(mandatory=true)
    public int m_bar;

    @Property(value="4")
    public int m_foo;
}

Using 'arch'

  • Deploy the 'arch' command bundle (available for Felix and Equinox)
  • Launch the 'arch' command in the OSGi Framework Shell 
    arch => displays instances name & state (equivalent to arch \-instances)
arch -instance $instance_name => displays complete information about the instance $instance_name
arch -factories => display the list of available factories
arch -factory $factory_name => display complete information about the factory $factory_name
arch -handlers => list available handlers
  • Architecture Handler
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