PVUtil¶

Helper methods for working with PV objects.

createPV( pvName, widget )

Create, start and return a PV attached to the given widget.

If the widget is destroyed (for example, because the display is closed), the PV goes down with it automatically.

The pvName argument can be any name that can also be used as a PV Name property. For example: loc://foo, /myproject/Voltage, =2 + 3, sim://noise, …

getDouble( pv )

Return a double representation for the current value of the given PV.

getDoubleArray( pv )

Return an array of doubles for the current value of the provided PV.

The array length is 1 if the value is not an array.

getLong( pv )

Return a long representation for the current value of the given PV.

getLongArray( pv )

Return an array of longs for the current value of the provided PV.

The array length is 1 if the value is not an array.

getString( pv )

Return a string representation for the current value of the given PV.

getStringArray( pv )

If pv is an array PV, return its current value as an array of strings, where each entry is a string representation of the actual value.

The array length is 1 if the value is not an array.

getTimeInMilliseconds( pv )

Returns the time for the PV’s current value as the number of milliseconds since the UNIX epoch. If the PV is backed by a Yamcs parameter, this would match that parameter’s generation time.

getTimeString( pv [, pattern] )

Return a formatted string for the timestamp of the PV’s current value. If the PV is backed by a Yamcs parameter, this would match that parameter’s generation time.

If the pattern argument is provided, it must be a string that follows Java conventions. See https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html

getSeverity( pv )

Returns the current severity of the given PV as a number with the following mapping:

• -1: UNDEFINED or INVALID

• 0: NONE

• 1: MAJOR

• 2: MINOR

getSeverityString( pv )

Returns the string value of the current severity of the given PV. One of UNDEFINED, INVALID, NONE, MINOR or MAJOR.

getLabels( pv )

Returns an array with all possible enum values for an enumerated PV.

getStatus( pv )

Returns the status text that might describe the severity specific to the type of PV.

For a Yamcs parameter this can be the value LOW, HIGH, LOLO, HIHI or NONE.

getSize( pv )

Return the array length of the current PV value. If the current value is not an array, returns 1.

getUnits( pv )

Returns the units text for a PV value.

writePV( pvName, value [, timeout] )

Write a value to a specific PV Name. In the background this will create a temporary PV object, write to it, and finally stop that PV.

A custom timeout in seconds may be provided. The default is 10 seconds.

This method has no return value. It returns immediately and does not wait for the write (or timeout) to occur.

Note

If you already have a connected PV instance x, it is simpler to call x.setValue(value) on it.

Example

Create a PV, listen to it, then write to it.

var IPVListener = Java.type("org.yamcs.studio.data.IPVListener");

var myPV = PVUtil.createPV("loc://test", widget);
myPV.addListener(new IPVListener({
    valueChanged: function(pv) {
        ConsoleUtil.writeInfo("Write successful: " + PVUtil.getString(pv));
    }
}));

ConsoleUtil.writeInfo("Writing...");
myPV.setValue(123);

Set a widget property based on a PV’s severity.

var severity = PVUtil.getSeverityString(pvs[0]);
var color;
switch (severity) {
    case "NONE":
        color = ColorFontUtil.GREEN;
        break;
    case "MAJOR":
        color = ColorFontUtil.RED;
        break;
    case "MINOR":
        color = ColorFontUtil.ORANGE;
        break;
    default:
        color = ColorFontUtil.PINK;
}
widget.setPropertyValue("foreground_color", color);