com.lightningkite.lightningdb.SortPart.kt Maven / Gradle / Ivy

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@file:SharedCode
package com.lightningkite.lightningdb

import com.lightningkite.khrysalis.IsCodableAndHashable
import com.lightningkite.khrysalis.SharedCode
import kotlinx.serialization.Serializable
import kotlin.reflect.KProperty1

@Serializable(SortPartSerializer::class)
@Description("The name of the property to sort by.  Prepend a '-' if you wish to sort descending.")
data class SortPart(
    val field: DataClassPathPartial,
    val ascending: Boolean = true,
    val ignoreCase: Boolean = false
) {
    constructor(field: KProperty1, ascending: Boolean = true, ignoreCase: Boolean = false):this(DataClassPathAccess(DataClassPathSelf(), field), ascending, ignoreCase)
}

val  List>.comparator: Comparator? get() {
    if(this.isEmpty()) return null
    return Comparator { a, b ->
        for(part in this) {
            if (part.ignoreCase) {
                val aString = part.field.getAny(a) as String
                val bString = part.field.getAny(b) as String
                val result = aString.compareTo(bString, true)
                if(result != 0) return@Comparator if(part.ascending) result else -result
            } else {
                val result = part.field.compare.compare(a, b)
                if(result != 0) return@Comparator if(part.ascending) result else -result
            }
        }
        return@Comparator 0
    }
}