Telemetry

A thin wrapper over the FTC SDK's telemetry that collects named entries — many backed by live suppliers — and lets you switch which groups of them are shown on the driver station by tag.

The telemetry package lives in com.cdarobotics.cdalib.telemetry. A TelemetryManager holds a list of Entry objects. Each entry has a label, a value supplier that is re-fetched every time the entry is displayed, and a tag grouping it with related entries. When you call displayTelemetry(), only entries whose tag is in the active display set are pushed to the driver station.

Entry

A single telemetry line: a label paired with a Supplier<String>, grouped under a tag. The value is not stored — it is pulled from the supplier fresh on every display, so an entry always shows the current reading.

Member	Signature	Description
constructor	`Entry(String tag, String label, Supplier<String> supplier)`	Creates an entry in the given group.
constructor	`Entry(String label, Supplier<String> supplier)`	Creates an entry in the `"default"` group.
`getLabel`	`String getLabel()`	Returns the label.
`getValue`	`String getValue()`	Calls the supplier and returns the current value (re-fetched each call).
`getTag`	`String getTag()`	Returns the group tag.

Values are strings and are live. A supplier is invoked at display time, so () -> String.valueOf(motor.getCurrentPosition()) always shows the latest position with no manual refresh. Convert non-string values yourself inside the supplier.

TelemetryManager

Constructed with the OpMode's Telemetry backend, it accumulates entries and tracks which tags are currently displayed.

Method	Description
`TelemetryManager(Telemetry telemetry)`	Creates a manager that renders entries to the given FTC telemetry backend.
`void addEntry(Entry entry)`	Registers an already-built `Entry`.
`void addEntry(String tag, String label, Supplier<String> supplier)`	Builds and registers an entry with an explicit group tag.
`void addEntry(String label, Supplier<String> supplier)`	Builds and registers an entry in the `"default"` group.
`void setDisplayTags(String... tags)`	Adds the given tags to the set of groups shown by `displayTelemetry()`.
`void removeDisplayTags(String... tags)`	Removes the given tags from the displayed set.
`void displayTelemetry()`	Renders every registered entry whose tag is in the active display set (values re-fetched from their suppliers), then calls `telemetry.update()` to push the batch to the driver station.

How lines are labeled. Each displayed entry is written as [tag] label paired with its value, so you can see at a glance which group a line belongs to on the driver station.

Nothing shows until a tag is active. setDisplayTags is additive and the display set starts empty — including "default". If your entries use the default group, call setDisplayTags("default") once, or nothing will appear. Entries display in tag order: for each active tag, all matching entries are rendered.

Example

Build a manager, register a mix of default and tagged entries, choose which groups to show, and display them in the loop.

TelemetryManager tm = new TelemetryManager(telemetry);

// Default-group entries (tag = "default")
tm.addEntry("Heading", () -> String.valueOf(follower.getPose().getHeading()));
tm.addEntry("Loop ms", () -> String.valueOf(loopTimer.milliseconds()));

// A grouped entry for arm debugging
tm.addEntry("arm", "Arm ticks", () -> String.valueOf(armMotor.getCurrentPosition()));
tm.addEntry("arm", "Arm target", () -> String.valueOf(arm.getTarget()));

// Prebuilt Entry, added directly
tm.addEntry(new Entry("drive", "Slow mode",
        () -> String.valueOf(bindingManager.checkBinding("slowMode"))));

// Choose which groups are visible
tm.setDisplayTags("default", "arm");   // show default + arm, hide "drive"

Then, once per loop:

tm.displayTelemetry();   // re-fetches every visible entry's value, then updates the DS

Toggle groups on and off at runtime — for example, reveal the drive group only while debugging:

tm.setDisplayTags("drive");        // start showing the drive group too
// ...later...
tm.removeDisplayTags("drive");     // hide it again