A.5.2 Hierarchy Browser

File load Hierarchy Browser window

By selecting the Hierarchy Browser option from the Load Window's DataSources menu, you can obtain a browser which presents a table-aware hierarchical view of the file system. (Note that a freestanding version of this panel with additional functionality is available in the separate Treeview application).

This browser resembles the Filestore Browser in some ways, but with important differences:

• It shows the file system in a 'tree-like' fashion, so that multiple levels of the hierarchy are displayed at once
• It understands which items in the hierarchy represent tables that can be automatically detected and which represent other kinds of object (for instance directories, zip files, or plain text files)
• It can look inside hierarchical files, so for instance it can investigate a Tar or Zip archive which may contain table entries, or display multiple tabular HDUs in a FITS file, or multiple TABLE elements at different levels in a VOTable document

The main part of the window shows a "tree" representation of the hierarchy, initially rooted at the current directory (the initial directory can be changed by setting the user.dir system property). Each line displayed represents a "node" which may be a file or some other type of item (for instance an HDU in a FITS file or an entry in a tar archive). The line contains a little icon which indicates what kind of node it is and a short text string which gives its name and maybe some description. Nodes which represent tables are indicated by the icon. For nodes which have some internal structure there is also a "handle" which indicates whether they are collapsed () or expanded (). You can examine remote filespaces (MySpace, SRB) as well as local ones in the same way as with the Filestore Browser.

If you select a node by clicking on it, it will be highlighted and some additional description will appear in the panel below the hierarchy display. The text is in bold if the node in question can be opened as a table, and non-bold if it is some non-table item.

Note: an important restriction of this browser is that it will only pick up tables which can be identified automatically - this includes FITS and VOTable files, but does not include text-based formats such as ASCII and Comma-Separated Values. If you want to load one of the latter types of table, you will need to use one of the other load methods and specify table format explicitly.

You can see how this browser works on an example directory of tables as described in Appendix A.5.6.

Note that this window requires certain optional components of the TOPCAT installation, and will not be available if you have the topcat-lite configuration.

• A.5.2.1 Navigation
• A.5.2.2 Table Searches