File DataSource

PV syntax

The standard prefix for the datasource is file:// which can be omitted if configured as the default datasource.

This datasource allows to read files and treat the contents as a source of data. Whenever a file is updated, the file is reparsed and a notification is sent with the new value.

• On Windows: file:///C:/Users/carcassi/mydata.csv will open the file located at C:\Users\carcassi\mydata.csv
• On Unix: file:///home/foo/mydata.csv will open the file located at /home/foo/mydata.csv

Supported formats

This package provides support for:

• Comma separated values (.csv) - The first line represents the column names and the subsequent lines represents rows of the table. Each element is separated by a comma. Strings must be quoted with a double quote. They are parsed into VTable.
• Images (.bmp, .jpg, .png) - They are parsed into VImage.
• List (.list) - Each line represents an element of the list. If all elements can be parsed to a number, it is treated as a list of numbers. They are parsed into VStringArray or VNumberArray.

Limitations

Changes are detected through OS callback if available and supported by the Java JDK. This gives very good performance (no extra load on CPU or disk) but is not available for all systems. In particular, is not available through network file systems (such as NFS).