Add a new class Trace which holds the global state for the trace implementation. (#201)

* Add a new class Tracing which holds the global state for the trace component.
* Update names of the classes and comments. TraceService -> TraceComponent and Trace -> Tracing.
* Make all methods in TraceComponent abstract to allow dependency injection.

6 files changed, 12 insertions, 6 deletions

diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicContextTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicContextTracing.java
index 33cdfcc7..11a37dfe 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicContextTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicContextTracing.java
@@ -16,6 +16,7 @@ package com.google.instrumentation.examples.trace;
 import com.google.instrumentation.common.NonThrowingCloseable;
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /**
  * Example showing how to create a {@link Span}, install it to the current context and add
@@ -23,7 +24,7 @@ import com.google.instrumentation.trace.Tracer;
  */
 public final class BasicContextTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doWork() {
     // Add an annotation to the current Span.
diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicScopedTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicScopedTracing.java
index ced5a962..4eddf800 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicScopedTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicScopedTracing.java
@@ -16,6 +16,7 @@ package com.google.instrumentation.examples.trace;
 import com.google.instrumentation.common.NonThrowingCloseable;
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /**
  * Example showing how to create a {@link Span} using scoped Span, install it in the current
@@ -23,7 +24,7 @@ import com.google.instrumentation.trace.Tracer;
  */
 public final class BasicScopedTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doWork() {
     // Add an annotation to the current Span.
diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicTracing.java
index ef05affa..1a78aebe 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/BasicTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/BasicTracing.java
@@ -15,11 +15,12 @@ package com.google.instrumentation.examples.trace;
 
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /** Example showing how to create a {@link Span} and add annotations. */
 public final class BasicTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doWork() {
     Span span = tracer.spanBuilder(null, "MyRootSpan").startSpan();
diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansContextTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansContextTracing.java
index c68a2e74..d00c1869 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansContextTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansContextTracing.java
@@ -16,6 +16,7 @@ package com.google.instrumentation.examples.trace;
 import com.google.instrumentation.common.NonThrowingCloseable;
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /**
  * Example showing how to create a child {@link Span}, install it to the current context and add
@@ -23,7 +24,7 @@ import com.google.instrumentation.trace.Tracer;
  */
 public final class MultiSpansContextTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doSomeOtherWork() {
     tracer.getCurrentSpan().addAnnotation("Annotation to the child Span");
diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansScopedTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansScopedTracing.java
index 9f9b1df2..25279f21 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansScopedTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansScopedTracing.java
@@ -16,6 +16,7 @@ package com.google.instrumentation.examples.trace;
 import com.google.instrumentation.common.NonThrowingCloseable;
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /**
  * Example showing how to create a child {@link Span} using scoped Spans, install it in the current
@@ -23,7 +24,7 @@ import com.google.instrumentation.trace.Tracer;
  */
 public final class MultiSpansScopedTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doSomeOtherWork() {
     tracer.getCurrentSpan().addAnnotation("Annotation to the child Span");
diff --git a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansTracing.java b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansTracing.java
index 80d5ba28..b3c3dbcd 100644
--- a/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansTracing.java
+++ b/examples/src/main/java/com/google/instrumentation/examples/trace/MultiSpansTracing.java
@@ -15,11 +15,12 @@ package com.google.instrumentation.examples.trace;
 
 import com.google.instrumentation.trace.Span;
 import com.google.instrumentation.trace.Tracer;
+import com.google.instrumentation.trace.Tracing;
 
 /** Example showing how to directly create a child {@link Span} and add annotations. */
 public final class MultiSpansTracing {
   // Per class Tracer.
-  private static final Tracer tracer = Tracer.getTracer();
+  private static final Tracer tracer = Tracing.getTracer();
 
   private static void doWork() {
     Span rootSpan = tracer.spanBuilder(null, "MyRootSpan").startSpan();