Refactor some null checks

theodolite/src/main/kotlin/theodolite/evaluation/ExternalSloChecker.kt

@@ -8,8 +8,7 @@ import java.net.ConnectException
 /**
  * [SloChecker] that uses an external source for the concrete evaluation.
  * @param externalSlopeURL The url under which the external evaluation can be reached.
- * @param threshold threshold that should not be exceeded to evaluate to true.
- * @param warmup time that is not taken into consideration for the evaluation.
+ * @param metadata metadata passed to the external SLO checker.
  */
 class ExternalSloChecker(
     private val externalSlopeURL: String,
@@ -26,19 +25,16 @@ class ExternalSloChecker(
      * Will try to reach the external service until success or [RETRIES] times.
      * Each request will timeout after [TIMEOUT].
      *
-     * @param start point of the experiment.
-     * @param end point of the experiment.
      * @param fetchedData that should be evaluated
-     * @return true if the experiment was successful(the threshold was not exceeded.
+     * @return true if the experiment was successful (the threshold was not exceeded).
      * @throws ConnectException if the external service could not be reached.
      */
     override fun evaluate(fetchedData: List<PrometheusResponse>): Boolean {
         var counter = 0
-        val data = SloJson.Builder()
-            .results(fetchedData.map { it.data?.result })
-            .addMetadata(metadata)
-            .build()
-            .toJson()
+        val data = SloJson(
+            results = fetchedData.map { it.data?.result ?: listOf() },
+            metadata = metadata
+        ).toJson()
 
         while (counter < RETRIES) {
             val result = post(externalSlopeURL, data = data, timeout = TIMEOUT)

theodolite/src/main/kotlin/theodolite/evaluation/SloJson.kt

@@ -3,58 +3,17 @@ package theodolite.evaluation
 import com.google.gson.Gson
 import theodolite.util.PromResult
 
-class SloJson private constructor(
-    val results: List<List<PromResult>?>? = null,
-    var metadata: MutableMap<String, Any>? = null
+class SloJson constructor(
+    val results: List<List<PromResult>>,
+    var metadata: Map<String, Any>
 ) {
 
-    data class Builder(
-        var results:List<List<PromResult>?>? = null,
-        var metadata: MutableMap<String, Any>? = null
-    ) {
-
-        /**
-         *  Set the results
-         *
-         * @param results list of prometheus results
-         */
-        fun results(results: List<List<PromResult>?>) = apply { this.results = results }
-
-        /**
-         * Add metadata as key value pairs
-         *
-         * @param key key of the metadata to be added
-         * @param value value of the metadata to be added
-         */
-        fun addMetadata(key: String, value: Any) = apply {
-            if (this.metadata.isNullOrEmpty()) {
-                this.metadata = mutableMapOf(key to value)
-            } else {
-                this.metadata!![key] = value
-            }
-        }
-
-        /**
-         * Add metadata as map of key value pairs.
-         *
-         * @param metadata map of key-value pairs to be added to be added
-         */
-        fun addMetadata(metadata: Map<String, Any>) = apply {
-            for (entry in metadata) {
-                this.addMetadata(entry.key, entry.value)
-            }
-        }
-
-        fun build() = SloJson(
-            results = results,
-            metadata = metadata
+    fun toJson(): String {
+        return Gson().toJson(
+            mapOf(
+                "results" to this.results,
+                "metadata" to this.metadata
+            )
         )
     }
-
-   fun  toJson(): String {
-       return Gson().toJson(mapOf(
-           "results" to this.results,
-           "metadata" to this.metadata
-       ))
-    }
 }
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