org.apache.aries.util.filesystem
Interface IDirectoryFinder

public interface IDirectoryFinder

Provides a means by which a virtual directory can be cached and returned on demand.

A typical scenario for this interface is to implement it as a service which is used to hold virtual directories containing application installation artifacts, with this directory being retrieved when required during application installation (a URI identifying the virtual directory having been passed to the installation code).

Implementing classes should use URIs of the form idirfinder://?finderID=xxx&directoryID=yyy where the finder ID within the query part of the URI may be used to assist in determining the directory finder instance that can retrieve the virtual directory identified by the directory ID part (or alternatively, the URI as a whole). When implemented as a service, a directory finder should configure a corresponding service property of "finderID=xxx".

Field Summary

static String	IDIR_DIRECTORYID_KEY The key used in the query part of the URI whose corresponding value identifies the directory to be returned.
static String	IDIR_FINDERID_KEY The key used in the query part of the URI whose corresponding value assists in identifying the directory finder to be used.
static String	IDIR_SCHEME The scheme for directory finder URI ids.

Method Summary

IDirectory

retrieveIDirectory(URI id) Get the directory that corresponds to the given identifier, and remove it from the cache, or return null if no corresponding directory is found.

Field Detail

IDIR_SCHEME

static final String IDIR_SCHEME

The scheme for directory finder URI ids. Using this scheme enables code receiving such a URI to infer that it is intended for use with a IDirectoryFinder instance.

See Also:

Constant Field Values

IDIR_FINDERID_KEY

static final String IDIR_FINDERID_KEY

The key used in the query part of the URI whose corresponding value assists in identifying the directory finder to be used.

See Also:

Constant Field Values

IDIR_DIRECTORYID_KEY

static final String IDIR_DIRECTORYID_KEY

The key used in the query part of the URI whose corresponding value identifies the directory to be returned.

See Also:

Constant Field Values

Method Detail

retrieveIDirectory

IDirectory retrieveIDirectory(URI id)

Get the directory that corresponds to the given identifier, and remove it from the cache, or return null if no corresponding directory is found.

As the found directory is removed, it is not subsequently retrievable by re-issuing the request.

Parameters:

id - a URI that identifies the desired directory.

Returns:

IDirectory instance that corresponds to the given id URI, or null if unknown.