This is the documentation of the Service Dependency Resources of the everest iPOJO domain. Each service dependency of an iPOJO component instance is represented by an everest iPOJO service dependency resource.

Path

/ipojo/instance/$name/dependency/$id - Where $name stand for the name of the instance and $id for the identifier of the dependency.

Supported operations

• READ: get the current state of the service dependency.
• UPDATE: reconfigure the dependency
  • filter (string): the wanted silter for the dependency. May be null (or empty, it has the same meaning).
  • isAggregate (string): the wanted value for the isAggregate flag of the dependency. One of {“true”, “false”}. May be null.
  • isOptional (string): the wanted value for the isAggregate flag of the dependency. One of {“true”, “false”}. May be null.

NOTE: This type of resource is observable

Metadata

• id (string): The identifier of the dependency.
• specification (string): The specification of the service dependency.
• isNullable (boolean): The flag indicating if the dependency uses Nullable objects.
• isProxy (boolean): The flag indicating if the dependency uses proxies.
• defaultImplementation (string): The name of the dependency default implementation class. May be null.
• state (string): The current state of the dependency. One of {“RESOLVED”, “UNRESOLVED”, “BROKEN”}.
• policy (string): The current binding policy of the dependency. One of {“DYNAMIC_BINDING”, “STATIC_BINDING”, “DYNAMIC_PRIORITY_BINDING”, “CUSTOMIZED”}.
• comparator (string): The name of the service comparator class of the dependency. May be null.
• isAggregate (boolean): The flag indicating if the dependency is aggregate.
• isOptional (boolean): The flag indicating if the dependency is optional.
• isFrozen (boolean): The flag indicating if the dependency is frozen.
• __isFake (boolean): Set to true if the resource is a fake resource. Unset otherwise.

Relations

• matchingService[$i]: to all the OSGi services that are currently matching the dependency. $i stands for the service identifier.
• usedService[$i]: to all the OSGi services that are currently used the dependency. $i stands for the service identifier.

Supported Adaptations

• to org.apache.felix.ipojo.util.DependencyModel.class: to the iPOJO DependencyModel service object.
• to org.apache.felix.ipojo.handlers.dependency.DependencyDescription.class: to the iPOJO DependencyDescription of the dependency.

HOW-TOs

How to reconfigure dependencies

You can reconfigure dynamically service dependencies by sending an UPDATE request on their resource representation. Here is a quick example:

Request:

UPDATE /ipojo/instance/org.ow2.chameleon.everest.core.Everest-0/dependency/RootResource
- filter="(type=ipojo)"

Result:

{
  "state":"RESOLVED",
  "filter":"(type=ipojo)",
  ...
}

WARNING: Reconfiguring the isAggregate and/or isOptional flags may have very strange side effects on the dependency and containing component instance. Prepare for unforeseen consequences…

Example

READ /ipojo/instance/org.ow2.chameleon.everest.core.Everest-0/dependency/RootResource

{
  "state":"RESOLVED",
  "filter":"(type=ipojo)",
  "policy":"DYNAMIC_BINDING",
  "comparator":null,
  "isAggregate":true,
  "isOptional":true,
  "isFrozen":false,
  "__relations": {
    "matchingService[75]": {
      "href":"http://localhost:8080/everest/osgi/services/75",
      "action":"READ",
      "name":"matchingService[75]",
      "description":"Matching service with id '75'",
      "parameters":[]
    },
    "usedService[75]": {
      "href":"http://localhost:8080/everest/osgi/services/75",
      "action":"READ",
      "name":"usedService[75]",
      "description":"Used service with id '75'",
      "parameters":[]
    }
  },
  "__observable":true
}