'Are there performance benefits from separating data calculations from data formatting in Kotlin app?
I have a codebase where all my data calculations and data formatting occur within a single function. Are there any performance benefits to separating these out into separate functions or does separating them only improve readability?
I know that I should separate them but I don't really know all the reasons why.
Here is the function I am referring to:
private fun processData(data: ByteArray) {
progressBar.visibility = GONE
Log.d(TAG, "displayDiagnosticData: ")
val bmsVersionView = findViewById<TextView>(R.id.textview_bms_version)
val boardVersionView = findViewById<TextView>(R.id.textview_board_version)
val cellOneView = findViewById<TextView>(R.id.textview_cell_1)
val cellTwoView = findViewById<TextView>(R.id.textview_cell_2)
val cellThreeView = findViewById<TextView>(R.id.textview_cell_3)
val cellFourView = findViewById<TextView>(R.id.textview_cell_4)
val cellFiveView = findViewById<TextView>(R.id.textview_cell_5)
val cellSixView = findViewById<TextView>(R.id.textview_cell_6)
val cellSevenView = findViewById<TextView>(R.id.textview_cell_7)
val cellEightView = findViewById<TextView>(R.id.textview_cell_8)
val cellNineView = findViewById<TextView>(R.id.textview_cell_9)
val cellTenView = findViewById<TextView>(R.id.textview_cell_10)
val cellElevenView = findViewById<TextView>(R.id.textview_cell_11)
val cellTwelveView = findViewById<TextView>(R.id.textview_cell_12)
val cellThirteenView = findViewById<TextView>(R.id.textview_cell_13)
val cellFourteenView = findViewById<TextView>(R.id.textview_cell_14)
val packTotalView = findViewById<TextView>(R.id.textview_diagnostic_voltage)
val packSocView = findViewById<TextView>(R.id.textview_diagnostic_soc)
val chargeTempView = findViewById<TextView>(R.id.textview_charge_temp)
val dischargeTempView = findViewById<TextView>(R.id.textview_discharge_temp)
val chargeCurrentView = findViewById<TextView>(R.id.textview_diagnostic_charge_current)
// val dischargeCurrentView = findViewById<TextView>(R.id.textview_diagnostic_discharge_current)
val dischargeCircuitStateView = findViewById<TextView>(R.id.textview_discharge_circuit)
val chargeCircuitStateView = findViewById<TextView>(R.id.textview_charge_circuit)
val balanceCircuitStateView = findViewById<TextView>(R.id.textview_balance_circuit)
val emptyCircuitStateView = findViewById<TextView>(R.id.textview_empty_circuit)
val bmsVersion = data[0] + (data[1] * 256)
val cellOne = data[2].toDouble() / 100 + 3.52
val cellTwo = data[3].toDouble() / 100 + 3.52
val cellThree = data[4].toDouble() / 100 + 3.52
val cellFour = data[5].toDouble() / 100 + 3.52
val cellFive = data[6].toDouble() / 100 + 3.52
val cellSix = data[7].toDouble() / 100 + 3.52
val cellSeven = data[8].toDouble() / 100 + 3.52
val cellEight = data[9].toDouble() / 100 + 3.52
val cellNine = data[10].toDouble() / 100 + 3.52
val cellTen = data[11].toDouble() / 100 + 3.52
val cellEleven = data[12].toDouble() / 100 + 3.52
val cellTwelve = data[13].toDouble() / 100 + 3.52
val cellThirteen = data[14].toDouble() / 100 + 3.52
val cellFourteen = data[15].toDouble() / 100 + 3.52
val totalVoltage = 47.8 + (data[16].toDouble() / 10)
val chargeTempCelsius = data[19]
val dischargeTempCelsius = data[20]
val chargeTempFahr = (chargeTempCelsius * 9.0 / 5.0) + 32.0
val dischargeTempFahr = (dischargeTempCelsius * 9.0 / 5.0) + 32.0
val chargeCurrent = data[21]
// val dischargeCurrent = (data[23].toDouble() * 100 + data[22]).toInt()
val chargeCircuitState = data[25].toInt()
val dischargeCircuitState = data[26].toInt()
val balanceCircuitState = data[27].toInt()
val emptyCircuitState = data[28].toInt()
val chargeCircuit: String = if (chargeCircuitState == 1) {
"On"
}else {
"Off"
}
val dischargeCircuit: String = if (dischargeCircuitState == 1) {
"On"
}else {
"Off"
}
val balanceCircuit: String = if (balanceCircuitState == 1) {
"On"
}else {
"Off"
}
val emptyCircuit: String = if (emptyCircuitState == 1) {
"On"
}else {
"Off"
}
val bmsVersionString = SpannableString("BMS Version: $bmsVersion")
bmsVersionString.setSpan(StyleSpan(Typeface.BOLD), 0, 11, 0)
val boardVersionString = SpannableString("Board Version: 2.1")
boardVersionString.setSpan(StyleSpan(Typeface.BOLD), 0, 13, 0)
val cellOneString = SpannableString("Cell 1: %.2fV".format(cellOne))
cellOneString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellTwoString = SpannableString("Cell 2: %.2fV".format(cellTwo))
cellTwoString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellThreeString = SpannableString("Cell 3: %.2fV".format(cellThree))
cellThreeString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellFourString = SpannableString("Cell 4: %.2fV".format(cellFour))
cellFourString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellFiveString = SpannableString("Cell 5: %.2fV".format(cellFive))
cellFiveString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellSixString = SpannableString("Cell 6: %.2fV".format(cellSix))
cellSixString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellSevenString = SpannableString("Cell 7: %.2fV".format(cellSeven))
cellSevenString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellEightString = SpannableString("Cell 8: %.2fV".format(cellEight))
cellEightString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellNineString = SpannableString("Cell 9: %.2fV".format(cellNine))
cellNineString.setSpan(StyleSpan(Typeface.BOLD), 0, 6, 0)
val cellTenString = SpannableString("Cell 10: %.2fV".format(cellTen))
cellTenString.setSpan(StyleSpan(Typeface.BOLD), 0, 7, 0)
val cellElevenString = SpannableString("Cell 11: %.2fV".format(cellEleven))
cellElevenString.setSpan(StyleSpan(Typeface.BOLD), 0, 7, 0)
val cellTwelveString = SpannableString("Cell 12: %.2fV".format(cellTwelve))
cellTwelveString.setSpan(StyleSpan(Typeface.BOLD), 0, 7, 0)
val cellThirteenString = SpannableString("Cell 13: %.2fV".format(cellThirteen))
cellThirteenString.setSpan(StyleSpan(Typeface.BOLD), 0, 7, 0)
val cellFourteenString = SpannableString("Cell 14: %.2fV".format(cellFourteen))
cellFourteenString.setSpan(StyleSpan(Typeface.BOLD), 0, 7, 0)
val packTotalString = SpannableString("Pack Total: %.1fV".format(totalVoltage))
packTotalString.setSpan(StyleSpan(Typeface.BOLD), 0, 10, 0)
val socString = SpannableString("SOC: ${data[17].toInt()}%")
socString.setSpan(StyleSpan(Typeface.BOLD), 0, 3, 0)
val chargeTempString = SpannableString("Charge Temp: ${chargeTempFahr.toInt()}" + "°F")
chargeTempString.setSpan(StyleSpan(Typeface.BOLD), 0, 11, 0)
val dischargeTempString = SpannableString("Discharge Temp: ${dischargeTempFahr.toInt()}" + "°F")
dischargeTempString.setSpan(StyleSpan(Typeface.BOLD), 0, 15, 0)
val chargeCurrentString = SpannableString("Charge Current: $chargeCurrent" + "A")
chargeCurrentString.setSpan(StyleSpan(Typeface.BOLD), 0, 14, 0)
// val dischargeCurrentString = "Discharge Current: $dischargeCurrent" + "A"
val chargeCircuitStateString = SpannableString("Charge Circuit: $chargeCircuit")
chargeCircuitStateString.setSpan(StyleSpan(Typeface.BOLD), 0, 14, 0)
val dischargeCircuitStateString = SpannableString("Discharge Circuit: $dischargeCircuit")
dischargeCircuitStateString.setSpan(StyleSpan(Typeface.BOLD), 0, 17, 0)
val balanceCircuitStateString = SpannableString("Balance Circuit: $balanceCircuit")
balanceCircuitStateString.setSpan(StyleSpan(Typeface.BOLD), 0, 15, 0)
val emptyCircuitStateString = SpannableString("Empty Circuit: $emptyCircuit")
emptyCircuitStateString.setSpan(StyleSpan(Typeface.BOLD), 0, 13, 0)
bmsVersionView.text = bmsVersionString
boardVersionView.text = boardVersionString
cellOneView.text = cellOneString
cellTwoView.text = cellTwoString
cellThreeView.text = cellThreeString
cellFourView.text = cellFourString
cellFiveView.text = cellFiveString
cellSixView.text = cellSixString
cellSevenView.text = cellSevenString
cellEightView.text = cellEightString
cellNineView.text = cellNineString
cellTenView.text = cellTenString
cellElevenView.text = cellElevenString
cellTwelveView.text = cellTwelveString
cellThirteenView.text = cellThirteenString
cellFourteenView.text = cellFourteenString
packTotalView.text = packTotalString
packSocView.text = socString
chargeTempView.text = chargeTempString
dischargeTempView.text = dischargeTempString
chargeCurrentView.text = chargeCurrentString
// dischargeCurrentView.text = dischargeCurrentString
chargeCircuitStateView.text = chargeCircuitStateString
dischargeCircuitStateView.text = dischargeCircuitStateString
balanceCircuitStateView.text = balanceCircuitStateString
emptyCircuitStateView.text = emptyCircuitStateString
}
Solution 1:[1]
Performance? No. Maintainability? Yes. Separation of concerns is one of the core tenets of modern software architecture. Combining the two things makes a difficult to read, difficult to debug mess. Separating them allows you to concentrate on one thing at a time, and makes it easier for people maintaining the code (which may even be you 6 months from now when fixing a bug and you've forgotten how it works) to understand the logic and flow of the program.
That function you posted would not be accepted in any professional codebase. It's too long, it does too many things. It needs to be broken up.
Solution 2:[2]
Your bigger problem there is that you're repeating yourself, a lot. Not only does that make the whole thing longer, and arguably harder to read, it also makes it hard to maintain like Gabe says, and makes it far more likely a bug will sneak in there. Imagine you needed to add another row of cells - there's a lot of boilerplate involved, a lot of repetitive work, and that's where humans tend to mess up
Like as an example of the kind of thing you can do - see how your cell data is basically taken from a range of values in data, with the same calculation applied to each? You could do this instead:
val cells = (2..15).map { index -> data[index].toDouble() / 100 + 3.52 }
or, to keep things more explicit and separate:
// Except give this a good name since it's doing something specific
// Because this is some kind of conversion formula, putting it in its own function
// makes it easy to maintain and document, and it's clear exactly what it is
fun getCellValue(dataValue: Int) = dataValue.toDouble() / 100 + 3.52
val cells = (2..15).map { index -> getCellValue(data[index]) }
Now you have one or two lines replacing 14 lines of initialisation code. It's also easier to make changes - if the format of data changes, you can easily change the range of indices to use, or the formula applied to each value. It's one place, instead of on each line, where you have to update each one and make sure you haven't made a typo or skipped one.
And when you have structured data like that, it can make your other code easier to work with too - because instead of needing to work with separate variables, you can work with indices and loop over things instead of writing each step out:
// no need for a separate line for each with hardcoded values if you can work it out
// (Because it's a separate function, you can use it for the other display lines too,
// it's not cell-specific)
fun SpannableString.applyBoldPrefix() = apply {
val colonIndex = indexOf(':')
if (colonIndex >= 0) setSpan(StyleSpan(Typeface.BOLD), 0, colonIndex, 0)
}
// you could also just pass in the index and look up cells[index] here -
// this is a more functional approach, but whatever's good
fun getCellDisplayString(cellIndex: Int, cellData: Double) =
SpannableString("Cell ${cellIndex + 1}: %.2fV".format(cellData))
.applyBoldPrefix()
// lots of ways to define/grab a set of views programmatically - putting them all
// in a container you can look up is one way. You can also generate resource identifier
// strings, like "R.id.textview_cell_$i" and look that up
val cellTextViews = findViewById<ViewGroup>(R.id.containerHoldingCells)
.children.filterIsInstance<TextView>
// now you can just iterate over stuff to complete the repetitive task
cellTextViews.forEachIndexed { i, view ->
view.text = getCellDisplayString(i, cells[i])
}
That's about half your code right there. I wouldn't necessarily structure everything this way (I feel like given you're working with a data format here, a more formal structure definition would be helpful, and you can generalise more too) and it's a bit rough-and-ready, but hopefully it gives you a general sense of how you can cut things down, but also make it easier to maintain them and try out changes
Solution 3:[3]
I condensed my code a lot more and created functions to process separate chunks of data. I also was able to get rid of a lot of my repetitious code. For anyone who is interested, here is the updated code:
private fun String.withStyling() = SpannableString(this).apply {
setSpan(StyleSpan(Typeface.BOLD), 0, indexOfFirst { it == ':' }, 0)
}
private fun processDiagnosticData(data: ByteArray) {
binding.progressBarCyclic.visibility = GONE
Log.d(TAG, "displayDiagnosticData: ")
processCells(data)
processTemps(data[19], data[20])
processCircuits(data)
processOtherData(data)
}
// Process cells 1-14 and display.
private fun processCells(data: ByteArray) {
val cellViews = listOf(
binding.textviewCell1,
binding.textviewCell2,
binding.textviewCell3,
binding.textviewCell4,
binding.textviewCell5,
binding.textviewCell6,
binding.textviewCell7,
binding.textviewCell8,
binding.textviewCell9,
binding.textviewCell10,
binding.textviewCell11,
binding.textviewCell12,
binding.textviewCell13,
binding.textviewCell14
)
for ((i, cellView) in cellViews.withIndex()) {
val value = data[2 + i].toDouble() / 100 + 3.52
val cellNumberString = (i + 1).toString()
val formattedString = "Cell $cellNumberString: %.2fV".format(value).withStyling()
cellView.text = formattedString
}
}
// Process charge/discharge temps and display.
private fun processTemps(chargeTempCel: Byte, dischargeTempCel: Byte) {
val chargeTempFahr = chargeTempCel * 9.0 / 5.0 + 32.0
val dischargeTempFahr = dischargeTempCel * 9.0 / 5.0 + 32.0
val chargeTempString = "Charge Temp: $chargeTempFahr°F".withStyling()
val dischargeTempString = "Discharge Temp: $dischargeTempFahr°F".withStyling()
binding.textviewChargeTemp.text = chargeTempString
binding.textviewDischargeTemp.text = dischargeTempString
}
// Process circuit states and display.
private fun processCircuits(data: ByteArray) {
val circuitViews = listOf(
binding.textviewChargeCircuit,
binding.textviewDischargeCircuit,
binding.textviewBalanceCircuit,
binding.textviewEmptyCircuit
)
val circuitNames = listOf(
"Charge Circuit: ",
"Discharge Circuit: ",
"Balance Circuit: ",
"Empty Circuit: "
)
for ((i, circuit) in circuitViews.withIndex()) {
val value = if (data[25 + i].toInt() == 1) {
"On"
} else {
"Off"
}
val formattedString = (circuitNames[i] + value).withStyling()
circuit.text = formattedString
}
}
// Process the rest of the data and display.
private fun processOtherData(data: ByteArray) {
val totalVoltage = 47.8 + (data[16].toDouble() / 10)
val packSoc = data[17].toInt()
val chargeCurrent = data[21]
// val dischargeCurrent = (data[23].toDouble() * 100 + data[22]).toInt()
val bmsVersionString = "BMS Version: ${data[0] + (data[1] * 256)}".withStyling()
val boardVersionString = "Board Version: 2.1".withStyling()
val totalVoltageString = "Pack Total: %.1fV".format(totalVoltage).withStyling()
val packSocString = "SOC: ${packSoc}%".withStyling()
val chargeCurrentString = "Charge Current: ${chargeCurrent}A".withStyling()
// val dischargeCurrent = "Discharge Current: $dischargeCurrentA".withStyling()
binding.textviewBmsVersion.text = bmsVersionString
binding.textviewBoardVersion.text = boardVersionString
binding.textviewDiagnosticVoltage.text = totalVoltageString
binding.textviewDiagnosticSoc.text = packSocString
binding.textviewDiagnosticChargeCurrent.text = chargeCurrentString
// binding.textviewDiagnosticDischargeCurrent.text = dischargeCurrentString
}
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | Gabe Sechan |
| Solution 2 | |
| Solution 3 | Dylon Jaynes |