Package org.osgi.service.metatype.annotations

Annotation Interface AttributeDefinition

@Retention(CLASS) @Target(METHOD) public @interface AttributeDefinition
AttributeDefinition information for the annotated method.

Each method of a type annotated by ObjectClassDefinition has an implied AttributeDefinition annotation. This annotation is only used to specify non-default AttributeDefinition information.

The id of this AttributeDefinition is generated from the name of the annotated method as follows:

  • A single dollar sign ('$' \u0024) is removed unless it is followed by:
    • A low line ('_' \u005F) and a dollar sign in which case the three consecutive characters ( "$_$") are changed to a single hyphen-minus ('-' \u002D).
    • Another dollar sign in which case the two consecutive dollar signs ( "$$") are changed to a single dollar sign.
  • A low line ('_' \u005F) is changed to a full stop ( '.' \u002E) unless is it followed by another low line in which case the two consecutive low lines ("__") are changed to a single low line.
  • All other characters are unchanged.
  • If the type declaring the method also declares a PREFIX_ field whose value is a compile-time constant String, then the id is prefixed with the value of the PREFIX_ field.
However, if the type annotated by ObjectClassDefinition is a single-element annotation, then the id for the value method is derived from the name of the annotation type rather than the name of the method. In this case, the simple name of the annotation type, that is, the name of the class without any package name or outer class name, if the annotation type is an inner class, must be converted to the value method's id as follows:
  • When a lower case character is followed by an upper case character, a full stop ('.' \u002E) is inserted between them.
  • Each upper case character is converted to lower case.
  • All other characters are unchanged.
  • If the annotation type declares a PREFIX_ field whose value is a compile-time constant String, then the id is prefixed with the value of the PREFIX_ field.
This id is the value of the id attribute of the generate AD element and is used as the name of the corresponding configuration property.

This annotation is not processed at runtime. It must be processed by tools and used to contribute to a Meta Type Resource document for the bundle.

See Also:
  • "The AD element of a Meta Type Resource."

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    int
    cardinality
    The cardinality of this AttributeDefinition.
    String[]
    defaultValue
    The default value for this AttributeDefinition.
    String
    description
    The human readable description of this AttributeDefinition.
    String
    max
    The maximum value for this AttributeDefinition.
    String
    min
    The minimum value for this AttributeDefinition.
    String
    name
    The human readable name of this AttributeDefinition.
    Option[]
    options
    The option information for this AttributeDefinition.
    boolean
    required
    The required value for this AttributeDefinition.
    AttributeType
    type
    The type of this AttributeDefinition.

  • Element Details

    • name

      String name
      The human readable name of this AttributeDefinition.

      If not specified, the name of this AttributeDefinition is derived from the name of the annotated method. For example, low line ('_' \u005F), dollar sign ('$' \u0024), and hyphen-minus ('-' \u002D) are replaced with space (' ' \u0020) and space is inserted between camel case words.

      If the name begins with the percent sign ('%' \u0025), the name can be localized.

      See Also:
      • "The name attribute of the AD element of a Meta Type Resource."
      Default:
      ""

    • description

      String description
      The human readable description of this AttributeDefinition.

      If not specified, the description of this AttributeDefinition is the empty string.

      If the description begins with the percent sign ('%' \u0025), the description can be localized.

      See Also:
      • "The description attribute of the AD element of a Meta Type Resource."
      Default:
      ""

    • type

      AttributeType type
      The type of this AttributeDefinition.

      This must be one of the defined attributes types.

      If not specified, the type is derived from the return type of the annotated method. Return types of Class and Enum are mapped to STRING. If the return type is List, Set, Collection, Iterable or some type which can be determined at annotation processing time to

      1. be a subtype of Collection and
      2. have a public no argument constructor,
      then the type is derived from the generic type. For example, a return type of List<String> will be mapped to STRING. A return type of a single dimensional array is supported and the type is the component type of the array. Multi dimensional arrays are not supported. Annotation return types are not supported. Any unrecognized type is mapped to STRING. A tool processing the annotation should declare an error for unsupported return types.
      See Also:
      • "The type attribute of the AD element of a Meta Type Resource."
      Default:
      STRING

    • cardinality

      int cardinality
      The cardinality of this AttributeDefinition.

      If not specified, the cardinality is derived from the return type of the annotated method. For an array return type, the cardinality is a large positive value. If the return type is List, Set, Collection, Iterable or some type which can be determined at annotation processing time to

      1. be a subtype of Collection and
      2. have a public no argument constructor,
      the cardinality is a large negative value. Otherwise, the cardinality is 0.
      See Also:
      • "The cardinality attribute of the AD element of a Meta Type Resource."
      Default:
      0

    • min

      String min
      The minimum value for this AttributeDefinition.

      If not specified, there is no minimum value.

      See Also:
      • "The min attribute of the AD element of a Meta Type Resource."
      Default:
      ""

    • max

      String max
      The maximum value for this AttributeDefinition.

      If not specified, there is no maximum value.

      See Also:
      • "The max attribute of the AD element of a Meta Type Resource."
      Default:
      ""

    • defaultValue

      String[] defaultValue
      The default value for this AttributeDefinition.

      The specified values are concatenated into a comma delimited list to become the value of the default attribute of the generated AD element.

      If not specified and the annotated method is an annotation element that has a default value, then the value of this element is the default value of the annotated element. Otherwise, there is no default value.

      See Also:
      • "The default attribute of the AD element of a Meta Type Resource."
      Default:
      {}

    • required

      boolean required
      The required value for this AttributeDefinition.

      If not specified, the value is true.

      See Also:
      • "The required attribute of the AD element of a Meta Type Resource."
      Default:
      true

    • options

      Option[] options
      The option information for this AttributeDefinition.

      For each specified Option, an Option element is generated for this AttributeDefinition.

      If not specified, the option information is derived from the return type of the annotated method. If the return type is an enum, a single dimensional array of an enum, or a List, Set, Collection, Iterable or some type which can be determined at annotation processing time to

      1. be a subtype of Collection and
      2. have a public no argument constructor,
      with a generic type of an enum, then the value of this element has an Option for each value of the enum. The label and value of each Option are set to the name of the corresponding enum value. Otherwise, no Option elements will be generated.
      See Also:
      • "The Option element of a Meta Type Resource."
      Default:
      {}