Add helpers to get random ids (#292)

Deterministic ones if the almond.ids.random Java property is "0" or "false".
almond-sh · Dec 17, 2018 · 8e11ef6 · 8e11ef6
1 parent ff61315
commit 8e11ef6
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Showing 2 changed files with 26 additions and 4 deletions.
diff --git a/modules/scala/scala-interpreter/src/main/scala/almond/ScalaInterpreter.scala b/modules/scala/scala-interpreter/src/main/scala/almond/ScalaInterpreter.scala
@@ -7,6 +7,7 @@ import java.nio.file.{Files, Path, Paths}
 import java.util.UUID
 
 import almond.api.JupyterApi
+import almond.api.helpers.Display
 import almond.channels.ConnectionParameters
 import almond.internals._
 import almond.interpreter._
@@ -539,7 +540,7 @@ final class ScalaInterpreter(
                           DisplayData.text(res0)
                         case Some(r) =>
                           val d = r.add(
-                            DisplayData.text(res0).withId(UUID.randomUUID().toString),
+                            DisplayData.text(res0).withId(Display.newId()),
                             variables
                           )
                           outputHandler match {

diff --git a/modules/scala/scala-kernel-api/src/main/scala/almond/api/helpers/Display.scala b/modules/scala/scala-kernel-api/src/main/scala/almond/api/helpers/Display.scala
@@ -3,7 +3,8 @@ package almond.api.helpers
 import java.io.{BufferedInputStream, IOException}
 import java.net.{URL, URLConnection}
 import java.nio.file.{Files, Paths}
-import java.util.{Base64, UUID}
+import java.util.concurrent.atomic.AtomicInteger
+import java.util.{Base64, Locale, UUID}
 
 import almond.interpreter.api.DisplayData.ContentType
 import almond.interpreter.api.{DisplayData, OutputHandler}
@@ -21,8 +22,28 @@ final class Display(id: String, contentType: String) {
 
 object Display {
 
-  private def newId(): String =
-    UUID.randomUUID().toString
+  def useRandomIds(): Boolean =
+    sys.props
+      .get("almond.ids.random")
+      .forall(s => s == "1" || s.toLowerCase(Locale.ROOT) == "true")
+
+  private val idCounter = new AtomicInteger
+  private val divCounter = new AtomicInteger
+
+  def newId(): String =
+    if (useRandomIds())
+      UUID.randomUUID().toString
+    else
+      idCounter.incrementAndGet().toString
+
+  def newDiv(prefix: String = "data-"): String =
+    prefix + {
+      if (useRandomIds())
+        UUID.randomUUID().toString
+      else
+        divCounter.incrementAndGet().toString
+    }
+
 
   def markdown(content: String)(implicit outputHandler: OutputHandler): Display = {
     val id = newId()