The Extended Universal Resource Locator library

The NetBeans Filesystems implementation has been designed to make it separable from the rest of the IDE. The result is that it can be used as a library in other client- or server- side Java applications. We would like to encourage this, as it offers some distinct advantages over direct file access.

NetBeans 3.x uses a concept of a virtual filesystem, in which the user "mounts" directories that contain files the IDE is interested in. The mounting concept is very similar to Unix's concept of mounts. In its usage inside NetBeans, the set of mounted filesystems makes up the classpath for compilation, execution and debugging. NetBeans 4.x does not have user-visible mounts. It continues to use the Filesystems infrastructure internally.

Why use it?

Filesystems are an abstraction on top of java.io.File (in the case of local files), that provide a number of useful things:

• File storage is completely abstracted - third parties can create support for access to file-like objects stored in an arbitrary manner, such as in a database, or in a version control system.
• Built-in support for ZIP/JAR archives and XML-based filesystems and the ability to transparently use other filesystems supported by NetBeans (such as the FTP filesystem) by adding the necessary classes
• Supports listening for change events if a file is externally modified
• Ability to add arbitrary "status" data to a file object and be notified of changes on it
• Support for actions on file objects, allowing you to define what actions are possible on a given file (and dynamically update these), and then expose those actions through your user interface.

This only scratches the surface of how this library can be useful. For more details, see the download and examples page.

Further information

• Download instructions and examples, details of what the library can do
• The Filesystems API package javadoc for an overview of the org.openide.filesystems package and its contents
• The AbstractFileSystem class javadoc to see the most common parent class for filesystems implementations
• Browse the sources of the local filesystem implementation, to get an idea what you'd need to do to implement your own filesystem.