refactor(trace/api): Introduce type system for trace API

This change updates the trace API by introducing a limited type system
for the table columns. Previously, the table columns could have any
possible type representable by the JVM. With this change, we limit the
available types to a small type system.

4 files changed, 109 insertions, 71 deletions

diff --git a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTaskTableReader.kt b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTaskTableReader.kt
index f0db78b7..bb5eb668 100644
--- a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTaskTableReader.kt
+++ b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTaskTableReader.kt
@@ -24,8 +24,12 @@ package org.opendc.trace.wtf
 
 import org.opendc.trace.*
 import org.opendc.trace.conv.*
+import org.opendc.trace.util.convertTo
 import org.opendc.trace.util.parquet.LocalParquetReader
 import org.opendc.trace.wtf.parquet.Task
+import java.time.Duration
+import java.time.Instant
+import java.util.*
 
 /**
  * A [TableReader] implementation for the WTF format.
@@ -48,26 +52,39 @@ internal class WtfTaskTableReader(private val reader: LocalParquetReader<Task>)
         }
     }
 
-    override fun resolve(column: TableColumn<*>): Int = columns[column] ?: -1
+    private val COL_ID = 0
+    private val COL_WORKFLOW_ID = 1
+    private val COL_SUBMIT_TIME = 2
+    private val COL_WAIT_TIME = 3
+    private val COL_RUNTIME = 4
+    private val COL_REQ_NCPUS = 5
+    private val COL_PARENTS = 6
+    private val COL_CHILDREN = 7
+    private val COL_GROUP_ID = 8
+    private val COL_USER_ID = 9
 
-    override fun isNull(index: Int): Boolean {
-        check(index in 0..columns.size) { "Invalid column index" }
-        return get(index) == null
+    private val TYPE_PARENTS = TableColumnType.Set(TableColumnType.String)
+    private val TYPE_CHILDREN = TableColumnType.Set(TableColumnType.String)
+
+    override fun resolve(name: String): Int {
+        return when (name) {
+            TASK_ID -> COL_ID
+            TASK_WORKFLOW_ID -> COL_WORKFLOW_ID
+            TASK_SUBMIT_TIME -> COL_SUBMIT_TIME
+            TASK_WAIT_TIME -> COL_WAIT_TIME
+            TASK_RUNTIME -> COL_RUNTIME
+            TASK_REQ_NCPUS -> COL_REQ_NCPUS
+            TASK_PARENTS -> COL_PARENTS
+            TASK_CHILDREN -> COL_CHILDREN
+            TASK_GROUP_ID -> COL_GROUP_ID
+            TASK_USER_ID -> COL_USER_ID
+            else -> -1
+        }
     }
 
-    override fun get(index: Int): Any? {
-        val record = checkNotNull(record) { "Reader in invalid state" }
-        return when (index) {
-            COL_ID -> record.id
-            COL_WORKFLOW_ID -> record.workflowId
-            COL_SUBMIT_TIME -> record.submitTime
-            COL_WAIT_TIME -> record.waitTime
-            COL_RUNTIME -> record.runtime
-            COL_REQ_NCPUS, COL_GROUP_ID, COL_USER_ID -> getInt(index)
-            COL_PARENTS -> record.parents
-            COL_CHILDREN -> record.children
-            else -> throw IllegalArgumentException("Invalid column")
-        }
+    override fun isNull(index: Int): Boolean {
+        check(index in COL_ID..COL_USER_ID) { "Invalid column index" }
+        return false
     }
 
     override fun getBoolean(index: Int): Boolean {
@@ -89,35 +106,62 @@ internal class WtfTaskTableReader(private val reader: LocalParquetReader<Task>)
         throw IllegalArgumentException("Invalid column")
     }
 
+    override fun getFloat(index: Int): Float {
+        throw IllegalArgumentException("Invalid column")
+    }
+
     override fun getDouble(index: Int): Double {
         throw IllegalArgumentException("Invalid column")
     }
 
-    override fun close() {
-        reader.close()
+    override fun getString(index: Int): String {
+        val record = checkNotNull(record) { "Reader in invalid state" }
+        return when (index) {
+            COL_ID -> record.id
+            COL_WORKFLOW_ID -> record.workflowId
+            else -> throw IllegalArgumentException("Invalid column")
+        }
     }
 
-    private val COL_ID = 0
-    private val COL_WORKFLOW_ID = 1
-    private val COL_SUBMIT_TIME = 2
-    private val COL_WAIT_TIME = 3
-    private val COL_RUNTIME = 4
-    private val COL_REQ_NCPUS = 5
-    private val COL_PARENTS = 6
-    private val COL_CHILDREN = 7
-    private val COL_GROUP_ID = 8
-    private val COL_USER_ID = 9
+    override fun getUUID(index: Int): UUID? {
+        throw IllegalArgumentException("Invalid column")
+    }
 
-    private val columns = mapOf(
-        TASK_ID to COL_ID,
-        TASK_WORKFLOW_ID to COL_WORKFLOW_ID,
-        TASK_SUBMIT_TIME to COL_SUBMIT_TIME,
-        TASK_WAIT_TIME to COL_WAIT_TIME,
-        TASK_RUNTIME to COL_RUNTIME,
-        TASK_REQ_NCPUS to COL_REQ_NCPUS,
-        TASK_PARENTS to COL_PARENTS,
-        TASK_CHILDREN to COL_CHILDREN,
-        TASK_GROUP_ID to COL_GROUP_ID,
-        TASK_USER_ID to COL_USER_ID,
-    )
+    override fun getInstant(index: Int): Instant {
+        val record = checkNotNull(record) { "Reader in invalid state" }
+        return when (index) {
+            COL_SUBMIT_TIME -> record.submitTime
+            else -> throw IllegalArgumentException("Invalid column")
+        }
+    }
+
+    override fun getDuration(index: Int): Duration {
+        val record = checkNotNull(record) { "Reader in invalid state" }
+        return when (index) {
+            COL_WAIT_TIME -> record.waitTime
+            COL_RUNTIME -> record.runtime
+            else -> throw IllegalArgumentException("Invalid column")
+        }
+    }
+
+    override fun <T> getList(index: Int, elementType: Class<T>): List<T>? {
+        throw IllegalArgumentException("Invalid column")
+    }
+
+    override fun <T> getSet(index: Int, elementType: Class<T>): Set<T>? {
+        val record = checkNotNull(record) { "Reader in invalid state" }
+        return when (index) {
+            COL_PARENTS -> TYPE_PARENTS.convertTo(record.parents, elementType)
+            COL_CHILDREN -> TYPE_CHILDREN.convertTo(record.children, elementType)
+            else -> throw IllegalArgumentException("Invalid column")
+        }
+    }
+
+    override fun <K, V> getMap(index: Int, keyType: Class<K>, valueType: Class<V>): Map<K, V>? {
+        throw IllegalArgumentException("Invalid column")
+    }
+
+    override fun close() {
+        reader.close()
+    }
 }
diff --git a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTraceFormat.kt b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTraceFormat.kt
index e71253ac..c8408626 100644
--- a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTraceFormat.kt
+++ b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/WtfTraceFormat.kt
@@ -46,24 +46,23 @@ public class WtfTraceFormat : TraceFormat {
         return when (table) {
             TABLE_TASKS -> TableDetails(
                 listOf(
-                    TASK_ID,
-                    TASK_WORKFLOW_ID,
-                    TASK_SUBMIT_TIME,
-                    TASK_WAIT_TIME,
-                    TASK_RUNTIME,
-                    TASK_REQ_NCPUS,
-                    TASK_PARENTS,
-                    TASK_CHILDREN,
-                    TASK_GROUP_ID,
-                    TASK_USER_ID
-                ),
-                listOf(TASK_SUBMIT_TIME)
+                    TableColumn(TASK_ID, TableColumnType.String),
+                    TableColumn(TASK_WORKFLOW_ID, TableColumnType.String),
+                    TableColumn(TASK_SUBMIT_TIME, TableColumnType.Instant),
+                    TableColumn(TASK_WAIT_TIME, TableColumnType.Duration),
+                    TableColumn(TASK_RUNTIME, TableColumnType.Duration),
+                    TableColumn(TASK_REQ_NCPUS, TableColumnType.Int),
+                    TableColumn(TASK_PARENTS, TableColumnType.Set(TableColumnType.String)),
+                    TableColumn(TASK_CHILDREN, TableColumnType.Set(TableColumnType.String)),
+                    TableColumn(TASK_GROUP_ID, TableColumnType.Int),
+                    TableColumn(TASK_USER_ID, TableColumnType.Int)
+                )
             )
             else -> throw IllegalArgumentException("Table $table not supported")
         }
     }
 
-    override fun newReader(path: Path, table: String, projection: List<TableColumn<*>>?): TableReader {
+    override fun newReader(path: Path, table: String, projection: List<String>?): TableReader {
         return when (table) {
             TABLE_TASKS -> {
                 val reader = LocalParquetReader(path.resolve("tasks/schema-1.0"), TaskReadSupport(projection))
diff --git a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/parquet/TaskReadSupport.kt b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/parquet/TaskReadSupport.kt
index 8e7325de..a6087d9f 100644
--- a/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/parquet/TaskReadSupport.kt
+++ b/opendc-trace/opendc-trace-wtf/src/main/kotlin/org/opendc/trace/wtf/parquet/TaskReadSupport.kt
@@ -27,7 +27,6 @@ import org.apache.parquet.hadoop.api.InitContext
 import org.apache.parquet.hadoop.api.ReadSupport
 import org.apache.parquet.io.api.RecordMaterializer
 import org.apache.parquet.schema.*
-import org.opendc.trace.TableColumn
 import org.opendc.trace.conv.*
 
 /**
@@ -35,11 +34,11 @@ import org.opendc.trace.conv.*
  *
  * @param projection The projection of the table to read.
  */
-internal class TaskReadSupport(private val projection: List<TableColumn<*>>?) : ReadSupport<Task>() {
+internal class TaskReadSupport(private val projection: List<String>?) : ReadSupport<Task>() {
     /**
      * Mapping of table columns to their Parquet column names.
      */
-    private val colMap = mapOf<TableColumn<*>, String>(
+    private val colMap = mapOf(
         TASK_ID to "id",
         TASK_WORKFLOW_ID to "workflow_id",
         TASK_SUBMIT_TIME to "ts_submit",
diff --git a/opendc-trace/opendc-trace-wtf/src/test/kotlin/org/opendc/trace/wtf/WtfTraceFormatTest.kt b/opendc-trace/opendc-trace-wtf/src/test/kotlin/org/opendc/trace/wtf/WtfTraceFormatTest.kt
index c0eb3f08..2312035a 100644
--- a/opendc-trace/opendc-trace-wtf/src/test/kotlin/org/opendc/trace/wtf/WtfTraceFormatTest.kt
+++ b/opendc-trace/opendc-trace-wtf/src/test/kotlin/org/opendc/trace/wtf/WtfTraceFormatTest.kt
@@ -65,32 +65,28 @@ class WtfTraceFormatTest {
 
         assertAll(
             { assertTrue(reader.nextRow()) },
-            { assertEquals("362334516345962206", reader.get(TASK_ID)) },
-            { assertEquals("1078341553348591493", reader.get(TASK_WORKFLOW_ID)) },
-            { assertEquals(Instant.ofEpochMilli(245604), reader.get(TASK_SUBMIT_TIME)) },
-            { assertEquals(Duration.ofMillis(8163), reader.get(TASK_RUNTIME)) },
+            { assertEquals("362334516345962206", reader.getString(TASK_ID)) },
+            { assertEquals("1078341553348591493", reader.getString(TASK_WORKFLOW_ID)) },
+            { assertEquals(Instant.ofEpochMilli(245604), reader.getInstant(TASK_SUBMIT_TIME)) },
+            { assertEquals(Duration.ofMillis(8163), reader.getDuration(TASK_RUNTIME)) },
             {
                 assertEquals(
                     setOf("584055316413447529", "133113685133695608", "1008582348422865408"),
-                    reader.get(
-                        TASK_PARENTS
-                    )
+                    reader.getSet(TASK_PARENTS, String::class.java)
                 )
             },
         )
 
         assertAll(
             { assertTrue(reader.nextRow()) },
-            { assertEquals("502010169100446658", reader.get(TASK_ID)) },
-            { assertEquals("1078341553348591493", reader.get(TASK_WORKFLOW_ID)) },
-            { assertEquals(Instant.ofEpochMilli(251325), reader.get(TASK_SUBMIT_TIME)) },
-            { assertEquals(Duration.ofMillis(8216), reader.get(TASK_RUNTIME)) },
+            { assertEquals("502010169100446658", reader.getString(TASK_ID)) },
+            { assertEquals("1078341553348591493", reader.getString(TASK_WORKFLOW_ID)) },
+            { assertEquals(Instant.ofEpochMilli(251325), reader.getInstant(TASK_SUBMIT_TIME)) },
+            { assertEquals(Duration.ofMillis(8216), reader.getDuration(TASK_RUNTIME)) },
             {
                 assertEquals(
                     setOf("584055316413447529", "133113685133695608", "1008582348422865408"),
-                    reader.get(
-                        TASK_PARENTS
-                    )
+                    reader.getSet(TASK_PARENTS, String::class.java)
                 )
             },
         )