BenchmarkKeywords.kt

package com.example.benchmark

import androidx.benchmark.BenchmarkRule
import androidx.benchmark.measureRepeated
import androidx.test.ext.junit.runners.AndroidJUnit4
import org.junit.Rule
import org.junit.Test
import org.junit.runner.RunWith
import kotlin.reflect.KProperty

/**
 * @author themishkun on 2019-05-18.
 */

const val keyword = "keyword"
@RunWith(AndroidJUnit4::class)
class KeywordBenchmark {
    @get:Rule
    val benchmarkRule = BenchmarkRule()

    // Copy-pasted from JMH project
    // It helps to ensure that no dead code elimination happened
    object BlackHole {
        var obj1: Any = Any()
        var tlr = 1L
        var tlrMask = System.nanoTime()
        fun consume(obj: Any) {
            val tlr = this.tlr
            val tlrMask = this.tlrMask

            this.tlr = tlr * 0x5DEECE66DL + 0xBL and 0xFFFFFFFFFFFFL
            if (tlr and tlrMask == 0L) {
                // SHOULD ALMOST NEVER HAPPEN IN MEASUREMENT
                if (tlrMask != 0x7FFFFFFFFFFFFFFFL) {
                    this.tlrMask = (tlrMask shl 1) + 1
                }
                this.obj1 = obj
            }
        }
    }

    @Test
    fun getConst() {
        benchmarkRule.measureRepeated {
            BlackHole.consume(com.example.benchmark.keyword)
        }
    }

    @Test
    fun getVal() {
        val keyword = "keyword"
        benchmarkRule.measureRepeated {
            BlackHole.consume(keyword)
        }
    }

    @Test
    fun getKeyword() {
        val keyword by keyword
        benchmarkRule.measureRepeated {
            BlackHole.consume(keyword)
        }
    }

    @Test
    fun getKeywordObject() {
        val keyword by keywordClass()
        benchmarkRule.measureRepeated {
            BlackHole.consume(keyword)
        }
    }

    object keyword {
        operator fun getValue(thisRef: Any?, property: KProperty<*>): String = property.name
    }

    class keywordClass {
        operator fun getValue(thisRef: Any?, property: KProperty<*>): String = property.name
    }
}