Interface IExtensionPoint


  • public interface IExtensionPoint
    An extension point declared in a plug-in. Except for the list of extensions plugged in to it, the information available for an extension point is obtained from the declaring plug-in's manifest (plugin.xml) file.

    These registry objects are intended for relatively short-term use. Clients that deal with these objects must be aware that they may become invalid if the declaring plug-in is updated or uninstalled. If this happens, all methods except isValid() will throw InvalidRegistryObjectException. For extension point objects, the most common case is code in a plug-in dealing with one of the extension points it declares. These extension point objects are guaranteed to be valid while the plug-in is active. Code in a plug-in that has declared that it is not dynamic aware (or not declared anything) can also safely ignore this issue, since the registry would not be modified while it is active. However, code in a plug-in that declares that it is dynamic aware must be careful if it access the extension point object of a different plug-in, because it's at risk if that other plug-in is removed. Similarly, tools that analyze or display the extension registry are vulnerable. Client code can pre-test for invalid objects by calling isValid(), which never throws this exception. However, pre-tests are usually not sufficient because of the possibility of the extension point object becoming invalid as a result of a concurrent activity. At-risk clients must treat InvalidRegistryObjectException as if it were a checked exception. Also, such clients should probably register a listener with the extension registry so that they receive notification of any changes to the registry.

    This interface can be used without OSGi running.

    This interface is not intended to be implemented by clients.

    Restriction:
    This interface is not intended to be implemented by clients.
    • Method Detail

      • getConfigurationElements

        IConfigurationElement[] getConfigurationElements()
                                                  throws InvalidRegistryObjectException
        Returns all configuration elements from all extensions configured into this extension point. Returns an empty array if this extension point has no extensions configured, or none of the extensions contain configuration elements.
        Returns:
        the configuration elements for all extension configured into this extension point
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getNamespace

        String getNamespace()
                     throws InvalidRegistryObjectException
        Deprecated.
        As namespace is no longer restricted to the contributor name, use getNamespaceIdentifier() to obtain namespace name or getContributor() to get the name of the contributor of this registry element.

        In the past namespace was dictated by the name of the bundle. If bundle org.abc contributed registry element with Id of MyId, the namespace of the element was always set to org.abc, producing the qualified name of org.abc.MyId.

        The namespace used to be the same as the bundle name. As a result, the getNamespace() method was used both to obtain the name of the bundle and to obtain the namespace of a registry element.

        Since 3.2, the extension registry allows elements to specify qualified name. The extension point of the plug-in org.abc could specify org.zzz.MyExtPoint as an Id. In this case, namespace name is org.zzz, but the contributor name is org.abc.

        (The use of a simple Id is still a preferred way. Whenever possible, specify only the simple Id and let runtime take care of the rest.)

        If your code used the getNamespace() to obtain the name of the contributing bundle, use getContributor(). The typical usage pattern here is to find a bundle name to obtain some information from the corresponding OSGi bundle. For example, deducing the file location specified as a relative path to the bundle install location would fall into this group.

        If your code used the getNamespace() to obtain the namespace of the registry element, use getNamespaceIdentifier(). Typically, this is the case when code is trying to process registry elements belonging to some logical group. For example, processing notifications for all elements belonging to the org.abc namespace would fall into this category.

        Returns the namespace for this extension point. This value can be used in various global facilities to discover this extension point's provider.
        Returns:
        the namespace for this extension point
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
        Since:
        3.0
        See Also:
        IExtensionRegistry
      • getExtension

        IExtension getExtension​(String extensionId)
                         throws InvalidRegistryObjectException
        Returns the extension with the given unique identifier configured into this extension point, or null if there is no such extension. Since an extension might not have an identifier, some extensions can only be found via the getExtensions method.
        Parameters:
        extensionId - the unique identifier of an extension (e.g. "com.example.acme.main").
        Returns:
        an extension, or null
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getExtensions

        IExtension[] getExtensions()
                            throws InvalidRegistryObjectException
        Returns all extensions configured into this extension point. Returns an empty array if this extension point has no extensions.
        Returns:
        the extensions configured into this extension point
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getLabel

        String getLabel()
                 throws InvalidRegistryObjectException
        Returns a displayable label for this extension point. Returns the empty string if no label for this extension point is specified in the plug-in manifest file.

        Note that any translation specified in the plug-in manifest file is automatically applied.

        Returns:
        a displayable string label for this extension point, possibly the empty string
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getLabel

        String getLabel​(String locale)
                 throws InvalidRegistryObjectException
        When multi-language support is enabled, this method returns a displayable label for this extension point in the specified locale. Returns the empty string if no label for this extension point is specified in the plug-in manifest file.

        The locale matching tries to find the best match between available translations and the requested locale, falling back to a more generic locale ("en") when the specific locale ("en_US") is not available.

        If multi-language support is not enabled, this method is equivalent to the method getLabel().

        Parameters:
        locale - the requested locale
        Returns:
        a displayable string label for this extension point, possibly the empty string
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
        Since:
        3.5
        See Also:
        IExtensionRegistry.isMultiLanguage()
      • getSchemaReference

        String getSchemaReference()
                           throws InvalidRegistryObjectException
        Returns reference to the extension point schema. The schema reference is returned as a URL path relative to the plug-in installation URL. Returns the empty string if no schema for this extension point is specified in the plug-in manifest file.
        Returns:
        a relative URL path, or an empty string
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getSimpleIdentifier

        String getSimpleIdentifier()
                            throws InvalidRegistryObjectException
        Returns the simple identifier of this extension point. This identifier is a non-empty string containing no period characters ('.') and is guaranteed to be unique within the namespace.
        Returns:
        the simple identifier of the extension point (e.g. "builders")
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • getUniqueIdentifier

        String getUniqueIdentifier()
                            throws InvalidRegistryObjectException
        Returns the unique identifier of this extension point. This identifier is unique within the plug-in registry, and is composed of the namespace for this extension point and this extension point's simple identifier.
        Returns:
        the unique identifier of the extension point (e.g. "org.eclipse.core.resources.builders")
        Throws:
        InvalidRegistryObjectException - if this extension point is no longer valid
      • isValid

        boolean isValid()
        Returns whether this extension point object is valid.
        Returns:
        true if the object is valid, and false if it is no longer valid
        Since:
        3.1