rename ActiveSpanSource into ActiveSpanStorage

5 files changed, 79 insertions, 56 deletions

diff --git a/kamon-core/src/main/scala/kamon/Kamon.scala b/kamon-core/src/main/scala/kamon/Kamon.scala
index 6de45e25..7c3beb84 100644
--- a/kamon-core/src/main/scala/kamon/Kamon.scala
+++ b/kamon-core/src/main/scala/kamon/Kamon.scala
@@ -108,8 +108,6 @@ object Kamon extends MetricLookup with ReporterRegistry with Tracer {
   override def activate(span: Span): Scope =
     _tracer.activate(span)
 
-  override def activate(span: Span, finishOnClose: Boolean): Scope =
-    _tracer.activate(span, finishOnClose)
 
   /**
     * Makes the provided Span active before code is evaluated and deactivates it afterwards.
diff --git a/kamon-core/src/main/scala/kamon/trace/ActiveSpanSource.scala b/kamon-core/src/main/scala/kamon/trace/ActiveSpanSource.scala
deleted file mode 100644
index f4a363a6..00000000
--- a/kamon-core/src/main/scala/kamon/trace/ActiveSpanSource.scala
+++ /dev/null
@@ -1,46 +0,0 @@
-package kamon.trace
-
-
-trait Scope extends AutoCloseable {
-  def close(): Unit
-}
-
-trait ActiveSpanSource {
-  def activeSpan(): Span
-
-  def activate(span: Span): Scope
-  def activate(span: Span, finishOnClose: Boolean): Scope
-}
-
-object ActiveSpanSource {
-
-  final class ThreadLocalBased extends ActiveSpanSource {
-    private val emptySpan = Span.Empty(this)
-    private val storage: ThreadLocal[Span] = new ThreadLocal[Span] {
-      override def initialValue(): Span = emptySpan
-    }
-
-    override def activeSpan(): Span =
-      storage.get()
-
-    override def activate(span: Span): Scope =
-      activate(span, finishOnClose = false)
-
-    override def activate(span: Span, finishOnClose: Boolean): Scope = {
-      val previouslyActiveSpan = storage.get()
-      storage.set(span)
-
-      new Scope {
-        override def close(): Unit = {
-          storage.set(previouslyActiveSpan)
-          if (finishOnClose && span != null)
-            span.finish()
-        }
-      }
-    }
-  }
-
-  object ThreadLocalBased {
-    def apply(): ThreadLocalBased = new ThreadLocalBased()
-  }
-}
\ No newline at end of file
diff --git a/kamon-core/src/main/scala/kamon/trace/ActiveSpanStorage.scala b/kamon-core/src/main/scala/kamon/trace/ActiveSpanStorage.scala
new file mode 100644
index 00000000..85e94ef2
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/ActiveSpanStorage.scala
@@ -0,0 +1,74 @@
+package kamon.trace
+
+/**
+  * A means of storing and retrieving the currently active Span. The application code execution is always considered to
+  * contribute to the completion of the operation represented by the currently active Span.
+  *
+  * The activation of a Span is of temporary nature and users of this API must ensure that all Scopes created via calls
+  * to `activate(span)` are timely closed; failing to do so might lead to unexpected behavior. Typically, the same block
+  * of code designating a Span as currently active will close the created Scope after finishing execution.
+  *
+  */
+trait ActiveSpanStorage {
+
+  /**
+    * @return the currently active Span.
+    */
+  def activeSpan(): Span
+
+  /**
+    * Sets
+    * @param span the Span to be set as currently active.
+    * @return a [[Scope]] that will finish the designation of the given Span as active once it's closed.
+    */
+  def activate(span: Span): Scope
+
+}
+
+/**
+  * Encapsulates the state (if any) required to handle the removal of a Span from it's currently active designation.
+  *
+  * Typically a Scope will enclose the previously active Span and return the previously active Span when closed,
+  * although no assumptions are made.
+  *
+  */
+trait Scope extends AutoCloseable {
+
+  /**
+    * Removes the currently active Span from the ActiveSpanStorage.
+    *
+    */
+  def close(): Unit
+}
+
+object ActiveSpanStorage {
+
+  /**
+    * A ActiveSpanStorage that uses a [[java.lang.ThreadLocal]] as the underlying storage.
+    *
+    */
+  final class ThreadLocal extends ActiveSpanStorage {
+    private val emptySpan = Span.Empty(this)
+    private val storage: java.lang.ThreadLocal[Span] = new java.lang.ThreadLocal[Span] {
+      override def initialValue(): Span = emptySpan
+    }
+
+    override def activeSpan(): Span =
+      storage.get()
+
+    override def activate(span: Span): Scope = {
+      val previouslyActiveSpan = storage.get()
+      storage.set(span)
+
+      new Scope {
+        override def close(): Unit = {
+          storage.set(previouslyActiveSpan)
+        }
+      }
+    }
+  }
+
+  object ThreadLocal {
+    def apply(): ThreadLocal = new ThreadLocal()
+  }
+}
\ No newline at end of file
diff --git a/kamon-core/src/main/scala/kamon/trace/Span.scala b/kamon-core/src/main/scala/kamon/trace/Span.scala
index 6b38ae48..84cc5625 100644
--- a/kamon-core/src/main/scala/kamon/trace/Span.scala
+++ b/kamon-core/src/main/scala/kamon/trace/Span.scala
@@ -71,7 +71,7 @@ trait Span extends BaseSpan {
 
 object Span {
 
-  final class Empty(activeSpanSource: ActiveSpanSource) extends Span {
+  final class Empty(activeSpanSource: ActiveSpanStorage) extends Span {
     override val context: SpanContext = SpanContext.EmptySpanContext
 
     override def annotate(annotation: Annotation): Span = this
@@ -87,7 +87,7 @@ object Span {
   }
 
   object Empty {
-    def apply(activeSpanSource: ActiveSpanSource): Empty = new Empty(activeSpanSource)
+    def apply(activeSpanSource: ActiveSpanStorage): Empty = new Empty(activeSpanSource)
   }
 
   /**
@@ -99,7 +99,7 @@ object Span {
     * @param spanSink
     */
   final class Real(spanContext: SpanContext, initialOperationName: String, initialSpanTags: Map[String, Span.TagValue],
-    initialMetricTags: Map[String, String], startTimestampMicros: Long, spanSink: SpanSink, activeSpanSource: ActiveSpanSource) extends Span {
+    initialMetricTags: Map[String, String], startTimestampMicros: Long, spanSink: SpanSink, activeSpanSource: ActiveSpanStorage) extends Span {
 
     private var collectMetrics: Boolean = true
     private var open: Boolean = true
diff --git a/kamon-core/src/main/scala/kamon/trace/Tracer.scala b/kamon-core/src/main/scala/kamon/trace/Tracer.scala
index 737a8b8d..bfdd561d 100644
--- a/kamon-core/src/main/scala/kamon/trace/Tracer.scala
+++ b/kamon-core/src/main/scala/kamon/trace/Tracer.scala
@@ -29,7 +29,7 @@ import org.slf4j.LoggerFactory
 import scala.collection.immutable
 import scala.util.Try
 
-trait Tracer extends ActiveSpanSource {
+trait Tracer extends ActiveSpanStorage {
   def buildSpan(operationName: String): SpanBuilder
 
   def extract[C](format: SpanContextCodec.Format[C], carrier: C): Option[SpanContext]
@@ -41,7 +41,7 @@ object Tracer {
 
   final class Default(metrics: MetricLookup, reporterRegistry: ReporterRegistryImpl, initialConfig: Config) extends Tracer {
     private val logger = LoggerFactory.getLogger(classOf[Tracer])
-    private val activeSpanSource = ActiveSpanSource.ThreadLocalBased()
+    private val activeSpanSource = ActiveSpanStorage.ThreadLocal()
 
     private[Tracer] val tracerMetrics = new TracerMetrics(metrics)
     @volatile private[Tracer] var joinRemoteParentsWithSameSpanID: Boolean = true
@@ -79,9 +79,6 @@ object Tracer {
     override def activate(span: Span): Scope =
       activeSpanSource.activate(span)
 
-    override def activate(span: Span, finishOnClose: Boolean): Scope =
-      activeSpanSource.activate(span, finishOnClose)
-
     def sampler: Sampler =
       configuredSampler