merge: Introduce schema for trace API (#88)

This pull request updates the OpenDC trace API to support proper specification 
of a schema of the tables exposed by the traces. This functionality makes it easier 
for the API consumer to understand the types exposed by the API.

## Implementation Notes :hammer_and_pick:

* Introduce type system for trace API
* Add benchmarks for odcvm trace format 
* Add benchmarks for Azure trace format
* Add conformance suite for OpenDC trace API 

## External Dependencies :four_leaf_clover:

* N/A

## Breaking API Changes :warning:

* Removal of typed `TableColumn`. Instead, `TableColumn` instances are now 
   used to describe the columns belonging to some table.
* `TableReader` and `TableWriter` do not support accessing arbitrary objects 
   anymore. Instead, only the types supported by the type system are exposed.

1 files changed, 7 insertions, 9 deletions

diff --git a/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeWorkloadLoader.kt b/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeWorkloadLoader.kt
index 720c7e58..12c2325a 100644
--- a/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeWorkloadLoader.kt
+++ b/opendc-compute/opendc-compute-workload/src/main/kotlin/org/opendc/compute/workload/ComputeWorkloadLoader.kt
@@ -29,8 +29,6 @@ import org.opendc.trace.*
 import org.opendc.trace.conv.*
 import java.io.File
 import java.lang.ref.SoftReference
-import java.time.Duration
-import java.time.Instant
 import java.util.*
 import java.util.concurrent.ConcurrentHashMap
 import kotlin.math.max
@@ -68,9 +66,9 @@ public class ComputeWorkloadLoader(private val baseDir: File) {
 
         return try {
             while (reader.nextRow()) {
-                val id = reader.get(idCol) as String
-                val time = reader.get(timestampCol) as Instant
-                val duration = reader.get(durationCol) as Duration
+                val id = reader.getString(idCol)!!
+                val time = reader.getInstant(timestampCol)!!
+                val duration = reader.getDuration(durationCol)!!
                 val cores = reader.getInt(coresCol)
                 val cpuUsage = reader.getDouble(usageCol)
 
@@ -105,13 +103,13 @@ public class ComputeWorkloadLoader(private val baseDir: File) {
         return try {
             while (reader.nextRow()) {
 
-                val id = reader.get(idCol) as String
+                val id = reader.getString(idCol)!!
                 if (!fragments.containsKey(id)) {
                     continue
                 }
 
-                val submissionTime = reader.get(startTimeCol) as Instant
-                val endTime = reader.get(stopTimeCol) as Instant
+                val submissionTime = reader.getInstant(startTimeCol)!!
+                val endTime = reader.getInstant(stopTimeCol)!!
                 val cpuCount = reader.getInt(cpuCountCol)
                 val cpuCapacity = reader.getDouble(cpuCapacityCol)
                 val memCapacity = reader.getDouble(memCol) / 1000.0 // Convert from KB to MB
@@ -162,7 +160,7 @@ public class ComputeWorkloadLoader(private val baseDir: File) {
 
             while (reader.nextRow()) {
                 @Suppress("UNCHECKED_CAST")
-                val members = reader.get(membersCol) as Set<String>
+                val members = reader.getSet(membersCol, String::class.java)!!
                 val target = reader.getDouble(targetCol)
                 val score = reader.getDouble(scoreCol)