MapValue#equals too slow

[xuwei-k]

version 0.7.0-p2

import org.msgpack.value._

object Main {

 def mapValueEqualsTime(size: Int): Unit = {
 val keyValues: Array[Value] = (1 to size).flatMap{ key =>
 Seq(ValueFactory.newString(key.toString), ValueFactory.nilValue())
 }.toArray
 val map1, map2 = ValueFactory.newMap(keyValues)
 println(size)
 System.gc
 val start = System.nanoTime
 map1 == map2
 println((System.nanoTime - start) / 1000000.0)
 println
 }

 def main(args: Array[String]) {
 mapValueEqualsTime(10)
 mapValueEqualsTime(100)
 mapValueEqualsTime(1000)
 mapValueEqualsTime(10000)
 mapValueEqualsTime(100000)
 }

}

result

10
1.634357

100
4.078424

1000
10.137222

10000
183.871329

100000
22959.867596

[xerial]

New MapValue.equals is implemented by translating the value into a Map:
https://github.com/msgpack/msgpack-java/blob/v07-develop/msgpack-core/src/main/java/org/msgpack/value/impl/ImmutableMapValueImpl.java#L137-137

This implementation still might have this performance problem.