9.2.3 System properties

System properties are a way of getting information into Java (they are the Java equivalent of environment variables). The following ones have special significance within TOPCAT:

apple.laf.useScreenMenuBar

On the Apple Macintosh platform only, this property controls whether menus appear at the top of the screen as usual for Mac, or at the top of individual windows as usual for Java. By default when using Java 1.5 or later it is set to true for TOPCAT, so menus mostly appear at the top of the screen (though it's not true to say that TOPCAT obeys the Mac look and feel completely); if you prefer the more Java-like look and feel, set it to false. There are bugs with this feature in Apple's Java 1.4 JRE, so it's set false by default in that case, but you can try setting it true at your own risk if you like.

java.io.tmpdir

The directory in which TOPCAT will write any temporary files it needs. This is usually only done if the -disk flag has been specified (see Section 9.1).

jdbc.drivers

Can be set to a (colon-separated) list of JDBC driver classes using which SQL databases can be accessed (see Section 9.3).

jel.classes

Can be set to a (colon-separated) list of classes containing static methods which define user-provided functions for synthetic columns or subsets. (see Section 6.9).

jel.classes.activation

Can be set to a (colon-separated) list of classes containing static methods which define user-provided functions for use in custom activation expressions. (see Section 6.9).

lut.files

Can be set to a (colon-separated on *nix, semicolon-separated on Windows) list of files giving custom lookup tables for auxiliary axis and density map colour maps. Each file should be a text file containing a number of space-separated lines, each containing red, green, blue samples in the range 0-1. For instance the file

       1.0  1.0  0.0
       1.0  0.0  1.0
    

would give a colour map that fades from yellow to magenta. Any number of samples may be given; the scale is interpolated.

mark.workaround

If set to "true", this will work around a bug in the mark()/reset() methods of some java InputStream classes. These are rather common, including in Sun's J2SE system libraries. Use this if you are seeing errors that say something like "Resetting to invalid mark". Currently defaults to "false".

myspace.cache

If set to "true", this will prevent directories in the MySpace file browser from being read more than once. This is a workaround for MySpace performance problems at time of writing (April 2006); setting it true may lead to out of date file listings in MySpace, but it may be much faster. This behaviour may be withdrawn in future versions if MySpace performance improves. Currently defaults to "false".

star.connectors

Can be set to a (colon-separated) list of classes which provide access to remote filespace implementations. Thus-named classes should implement the uk.ac.starlink.connect.Connector interface which specifies how you can log on to such a service and provides a hierarchical view of the filespace it contains.

startable.load.dialogs

Can be set to a (colon-separated) list of custom table load dialogue classes. Briefly, you can install your own table import dialogues at runtime by providing classes which implement the uk.ac.starlink.table.gui.TableLoadDialog interface and naming them in this property. See STIL documentation for more detail.

startable.readers

Can be set to a (colon-separated) list of custom table format input handler classes (see Section 4.1.3).

startable.storage

Can be set to determine the default storage policy. Setting it to "disk" has basically the same effect as supplying the "-disk" argument on the TOPCAT command line (see Section 9.1). Other possible values are "memory" (the default), "sideways" and "discard".

startable.writers

Can be set to a (colon-separated) list of custom table format output handler classes (see Section 4.1.3).

user.dir

Sets the current working directory. This determines the default from which the file browsers will start.

votable.strict

Set true for strict enforcement of the VOTable standard when parsing VOTables. This prevents the parser from working round certain common errors, such as missing arraysize attributes on FIELD/PARAM elements with datatype="char". False by default.

To define these properties on the command line you use the -D flag, which has the form

    -D<property-name>=<value>

    topcat -Djdbc.drivers=org.postgresql.Driver ...

    java -Djdbc.drivers=org.postgresql.Driver ...

Alternatively you may find it more convenient to write these definitions in a file named .starjava.properties in your home directory; the above command-line flag would be equivalent to inserting the line:

    jdbc.drivers=org.postgresql.Driver