Moves method used by dependencies job to reduce internal class leak

Adrian Cole · Adrian Cole · commit ea5e01354f20 · 2016-07-20T11:38:33.000+08:00
DependencyLinker isn't stable, yet, and creating the input from pieces
requires a MergeById type that's also internal. By hiding this op,
callers have less internal classes in their imports.
diff --git a/zipkin/src/main/java/zipkin/internal/DependencyLinker.java b/zipkin/src/main/java/zipkin/internal/DependencyLinker.java
@@ -16,10 +16,12 @@
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.LinkedHashMap;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.logging.Logger;
 import zipkin.DependencyLink;
+import zipkin.Span;
 
 import static java.util.logging.Level.FINE;
 
@@ -36,6 +38,19 @@ public final class DependencyLinker {
 
   private final Map<Pair<String>, Long> linkMap = new LinkedHashMap<>();
 
+  /**
+   * @param spans spans where all spans have the same trace id
+   */
+  public DependencyLinker putTrace(List<Span> spans) {
+    if (spans.isEmpty()) return this;
+
+    List<DependencyLinkSpan> linkSpans = new LinkedList<>();
+    for (Span s : MergeById.apply(spans)) {
+      linkSpans.add(DependencyLinkSpan.from(s));
+    }
+    return putTrace(linkSpans.iterator());
+  }
+
   /**
    * @param spans spans where all spans have the same trace id
    */
diff --git a/zipkin/src/test/java/zipkin/internal/DependencyLinkerTest.java b/zipkin/src/test/java/zipkin/internal/DependencyLinkerTest.java
@@ -16,6 +16,7 @@
 import java.util.List;
 import org.junit.Test;
 import zipkin.DependencyLink;
+import zipkin.TestObjects;
 import zipkin.internal.DependencyLinkSpan.Kind;
 
 import static java.util.Arrays.asList;
@@ -28,6 +29,14 @@ public void baseCase() {
     assertThat(new DependencyLinker().link()).isEmpty();
   }
 
+  @Test
+  public void linksSpans() {
+    assertThat(new DependencyLinker().putTrace(TestObjects.TRACE).link()).containsExactly(
+        DependencyLink.create("web", "app", 1L),
+        DependencyLink.create("app", "db", 1L)
+    );
+  }
+
   /**
    * The linker links a directed graph, if the span kind is unknown, we don't know the direction to
    * link.
