cleaned up code and added additional test case

Author: liustve

aws-xray-propagator/src/main/java/io/opentelemetry/contrib/awsxray/propagator/AwsXrayPropagator.java

@@ -77,6 +77,7 @@ public final class AwsXrayPropagator implements TextMapPropagator {
   private static final int LINEAGE_MAX_LOOP_COUNTER = 32767;
   private static final int LINEAGE_MAX_REQUEST_COUNTER = 255;
   private static final int LINEAGE_MIN_COUNTER = 0;
+  private static final String INVALID_LINEAGE = "-1:11111111:0";
 
   private static final List<String> FIELDS = Collections.singletonList(TRACE_HEADER_KEY);
 
@@ -331,14 +332,14 @@ private static String parseLineageV2Header(String xrayLineageHeader) {
     if (xrayLineageHeader.length() < LINEAGE_MIN_LENGTH
         || xrayLineageHeader.length() > LINEAGE_MAX_LENGTH
         || numOfDelimiters != 2) {
-      return AwsXrayPropagator.getInvalidLineageV2Header();
+      return INVALID_LINEAGE;
     }
 
     return xrayLineageHeader;
   }
 
   private static boolean isValidLineage(String key) {
-    String[] split = key.split(":");
+    String[] split = key.split(String.valueOf(LINEAGE_DELIMITER));
     String hash = split[1];
     int loopCounter = parseIntOrReturnNegative(split[0]);
     int requestCounter = parseIntOrReturnNegative(split[2]);
@@ -352,10 +353,6 @@ private static boolean isValidLineage(String key) {
     return isHashValid && isValidRequestCounter && isValidLoopCounter;
   }
 
-  private static String getInvalidLineageV2Header() {
-    return "-1:11111111:0";
-  }
-
   @Nullable
   private static Boolean parseTraceFlag(String xraySampledFlag) {
     if (xraySampledFlag.length() != SAMPLED_FLAG_LENGTH) {

aws-xray-propagator/src/test/java/io/opentelemetry/contrib/awsxray/propagator/AwsXrayPropagatorTest.java

@@ -230,6 +230,32 @@ void extract_WithLineage() {
         .isEqualTo("32767:e65a2c4d:255");
   }
 
+  @Test
+  void extract_AddedLineagePreservesExistingBaggage() {
+    Baggage expectedBaggage =
+        Baggage.builder()
+            .put("cat", "meow")
+            .put("dog", "bark")
+            .put("Lineage", "32767:e65a2c4d:255")
+            .build();
+    Map<String, String> carrier = new LinkedHashMap<>();
+    carrier.put(
+        TRACE_HEADER_KEY,
+        "Root=1-8a3c60f7-d188f8fa79d48a391a778fa6;Parent=53995c3f42cd8ad8;Sampled=1;Lineage=32767:e65a2c4d:255");
+
+    Context context =
+        subject.extract(
+            Context.current().with(Baggage.builder().put("cat", "meow").put("dog", "bark").build()),
+            carrier,
+            GETTER);
+    assertThat(getSpanContext(context))
+        .isEqualTo(
+            SpanContext.createFromRemoteParent(
+                TRACE_ID, SPAN_ID, TraceFlags.getSampled(), TraceState.getDefault()));
+
+    assertThat(Baggage.fromContext(context).asMap()).isEqualTo(expectedBaggage.asMap());
+  }
+
   @Test
   void extract_inject_ValidTraceHeader() {
     Map<String, String> carrier1 = new LinkedHashMap<>();
@@ -395,7 +421,9 @@ static Stream<Arguments> providesBadLineages() {
         Arguments.of(":fbadc0de:13"),
         Arguments.of("1:fbadc0de:"),
         Arguments.of("1::1"),
-        Arguments.of("65535:fbadc0de:255"));
+        Arguments.of("65535:fbadc0de:255"),
+        Arguments.of("-213:e65a2c4d:255"),
+        Arguments.of("213:e65a2c4d:-22"));
   }
 
   @Test