Android Room parse before inserting

Question

Imagine receiving from an endpoint an object like this

data class Foo(
    val name: String,
    val start: String,
    val end: String
)

where the properties start and end are string in the format of "00:00:00" to represent the hours, minutes and second from midnight.

I need to save this object in a Room table but with start and end parsed as Int instead of string.

The solution I resorted is this:

data class Foo(
    val name: String,
    val start: String,
    val end: String,
    var startInSeconds: Int = 0,
    var endInSeconds: Int = 0
) {
    init {
        startInSeconds = this.convertTimeInSeconds(this.start)
        endInSeconds = this.convertTimeInSeconds(this.end)
    }

    private fun convertTimeInSeconds(time: String): Int {
        val tokens = time.split(":".toRegex())
        val hours = Integer.parseInt(tokens[0])
        val minutes = Integer.parseInt(tokens[1])
        val seconds = Integer.parseInt(tokens[2])
        return 3600 * hours + 60 * minutes + seconds
    }
}

But I'd like to avoid to parse the start and end every time.

There is a way to parse before inserting?

Answer 1

you can try my solution if you want ,

1. first, instead of using the same object Foo to store your data , it is better to create another data class as Entity to encapsulate the data.

data class Bar(
    val name: String,
    val start: String,
    val end: String,
    val startInSeconds: Int, // <<-- using val to make data read only
    val endInSeconds: Int // <<-- using val to make data read only
) 

2. you might need to create a thousand of object depend on your data size, so using companion object seems to be a good idea to parse the data to avoid unnecessary memory allocation .

data class Bar(
    val name: String,
    val start: String,
    val end: String,
    val startInSeconds: Int,
    val endInSeconds: Int
) {

  companion object {
        // overloading the invoke function
        operator fun invoke(foo:Foo) : Bar {
            return Bar(
               name = foo.name,
               start = foo.start,
               end = foo.end,
               startInSeconds = convertTimeInSeconds(foo.start),
               endInSeconds = convertTimeInSeconds(foo.end)
            )
        }

        private fun convertTimeInSeconds(time: String): Int {
           val tokens = time.split(":".toRegex())
           val hours = Integer.parseInt(tokens[0])
           val minutes = Integer.parseInt(tokens[1])
           val seconds = Integer.parseInt(tokens[2])
           return 3600 * hours + 60 * minutes + seconds
       }
    } 

}

//how to use
fun insertToDatabase(foo:Foo){
   val parsedData = Bar(foo)
   dao.insert(parsedData)
}