add shortcut methods to get tracers and meters (#1159)

* add shortcut methods to get tracers and meters

* add shortcut methods to get tracers and meters

* add shortcut methods to get tracers and meters

* add shortcut methods to get tracers and meters

QUICKSTART.md

@@ -40,7 +40,7 @@ monitored. More information is available in the specification chapter [Obtaining
 
 ```java
 Tracer tracer =
-    OpenTelemetry.getTracerProvider().get("instrumentation-library-name","semver:1.0.0");
+    OpenTelemetry.getTracer("instrumentation-library-name","semver:1.0.0");
 ```
 
 ### Create basic Span
@@ -255,7 +255,7 @@ The following is an example of counter usage:
 
 ```java
 // Gets or creates a named meter instance
-Meter meter = OpenTelemetry.getMeterProvider().get("instrumentation-library-name","semver:1.0.0");
+Meter meter = OpenTelemetry.getMeter("instrumentation-library-name","semver:1.0.0");
 
 // Build counter e.g. LongCounter 
 LongCounter counter = meter

api/src/main/java/io/opentelemetry/OpenTelemetry.java

@@ -74,6 +74,37 @@ public final class OpenTelemetry {
     return getInstance().tracerProvider;
   }
 
+  /**
+   * Gets or creates a named tracer instance.
+   *
+   * <p>This is a shortcut method for <code>getTracerProvider().get(instrumentationName)</code>.
+   *
+   * @param instrumentationName The name of the instrumentation library, not the name of the
+   *     instrument*ed* library (e.g., "io.opentelemetry.contrib.mongodb"). Must not be null.
+   * @return a tracer instance.
+   * @since 0.4.0
+   */
+  public static Tracer getTracer(String instrumentationName) {
+    return getTracerProvider().get(instrumentationName);
+  }
+
+  /**
+   * Gets or creates a named and versioned tracer instance.
+   *
+   * <p>This is a shortcut method for <code>
+   * getTracerProvider().get(instrumentationName, instrumentationVersion)</code>.
+   *
+   * @param instrumentationName The name of the instrumentation library, not the name of the
+   *     instrument*ed* library (e.g., "io.opentelemetry.contrib.mongodb"). Must not be null.
+   * @param instrumentationVersion The version of the instrumentation library (e.g.,
+   *     "semver:1.0.0").
+   * @return a tracer instance.
+   * @since 0.4.0
+   */
+  public static Tracer getTracer(String instrumentationName, String instrumentationVersion) {
+    return getTracerProvider().get(instrumentationName, instrumentationVersion);
+  }
+
   /**
    * Returns a singleton {@link MeterProvider}.
    *
@@ -86,6 +117,36 @@ public final class OpenTelemetry {
     return getInstance().meterProvider;
   }
 
+  /**
+   * Gets or creates a named meter instance.
+   *
+   * <p>This is a shortcut method for <code>getMeterProvider().get(instrumentationName)</code>.
+   *
+   * @param instrumentationName The name of the instrumentation library, not the name of the
+   *     instrument*ed* library.
+   * @return a tracer instance.
+   * @since 0.4.0
+   */
+  public static Meter getMeter(String instrumentationName) {
+    return getMeterProvider().get(instrumentationName);
+  }
+
+  /**
+   * Gets or creates a named and versioned meter instance.
+   *
+   * <p>This is a shortcut method for <code>
+   * getMeterProvider().get(instrumentationName, instrumentationVersion)</code>.
+   *
+   * @param instrumentationName The name of the instrumentation library, not the name of the
+   *     instrument*ed* library.
+   * @param instrumentationVersion The version of the instrumentation library.
+   * @return a tracer instance.
+   * @since 0.4.0
+   */
+  public static Meter getMeter(String instrumentationName, String instrumentationVersion) {
+    return getMeterProvider().get(instrumentationName, instrumentationVersion);
+  }
+
   /**
    * Returns a singleton {@link CorrelationContextManager}.
    *

api/src/test/java/io/opentelemetry/OpenTelemetryTest.java

@@ -118,7 +118,7 @@ public class OpenTelemetryTest {
   public void testTracerNotFound() {
     System.setProperty(TraceProvider.class.getName(), "io.does.not.exists");
     thrown.expect(IllegalStateException.class);
-    OpenTelemetry.getTracerProvider().get("testTracer");
+    OpenTelemetry.getTracer("testTracer");
   }
 
   @Test

api/src/test/java/io/opentelemetry/metrics/DoubleCounterTest.java

@@ -34,7 +34,7 @@ public class DoubleCounterTest {
   private static final String DESCRIPTION = "description";
   private static final String UNIT = "1";
 
-  private final Meter meter = OpenTelemetry.getMeterProvider().get("counter_double_test");
+  private final Meter meter = OpenTelemetry.getMeter("counter_double_test");
 
   @Test
   public void preventNonPrintableName() {

api/src/test/java/io/opentelemetry/metrics/DoubleObserverTest.java

@@ -30,7 +30,7 @@ import org.junit.runners.JUnit4;
 public class DoubleObserverTest {
   @Rule public ExpectedException thrown = ExpectedException.none();
 
-  private final Meter meter = OpenTelemetry.getMeterProvider().get("observer_double_test");
+  private final Meter meter = OpenTelemetry.getMeter("observer_double_test");
 
   @Test
   public void preventNonPrintableName() {

api/src/test/java/io/opentelemetry/metrics/LongCounterTest.java

@@ -34,7 +34,7 @@ public class LongCounterTest {
   private static final String DESCRIPTION = "description";
   private static final String UNIT = "1";
 
-  private final Meter meter = OpenTelemetry.getMeterProvider().get("counter_long_test");
+  private final Meter meter = OpenTelemetry.getMeter("counter_long_test");
 
   @Test
   public void preventNonPrintableName() {

api/src/test/java/io/opentelemetry/metrics/LongObserverTest.java

@@ -30,7 +30,7 @@ import org.junit.runners.JUnit4;
 public class LongObserverTest {
   @Rule public ExpectedException thrown = ExpectedException.none();
 
-  private final Meter meter = OpenTelemetry.getMeterProvider().get("observer_long_test");
+  private final Meter meter = OpenTelemetry.getMeter("observer_long_test");
 
   @Test
   public void preventNonPrintableName() {

api/src/test/java/io/opentelemetry/trace/attributes/SemanticAttributesTest.java

@@ -37,7 +37,7 @@ public class SemanticAttributesTest {
 
   @Before
   public void setUp() {
-    Tracer tracer = OpenTelemetry.getTracerProvider().get("io.telemetry.api");
+    Tracer tracer = OpenTelemetry.getTracer("io.telemetry.api");
     span = tracer.spanBuilder("junit").startSpan();
   }
 

contrib/runtime_metrics/src/main/java/io/opentelemetry/contrib/metrics/runtime/GarbageCollector.java

@@ -50,7 +50,7 @@ public final class GarbageCollector {
   /** Constructs a new module that is capable to export metrics about "jvm_gc". */
   public GarbageCollector() {
     this.garbageCollectors = ManagementFactory.getGarbageCollectorMXBeans();
-    this.meter = OpenTelemetry.getMeterProvider().get("jvm_gc");
+    this.meter = OpenTelemetry.getMeter("jvm_gc");
   }
 
   /** Export all metrics generated by this module. */

contrib/runtime_metrics/src/main/java/io/opentelemetry/contrib/metrics/runtime/MemoryPools.java

@@ -63,7 +63,7 @@ public final class MemoryPools {
   public MemoryPools() {
     this.memoryBean = ManagementFactory.getMemoryMXBean();
     this.poolBeans = ManagementFactory.getMemoryPoolMXBeans();
-    this.meter = OpenTelemetry.getMeterProvider().get("jvm_memory");
+    this.meter = OpenTelemetry.getMeter("jvm_memory");
   }
 
   /** Export only the "area" metric. */

examples/grpc/src/main/java/io/opentelemetry/example/HelloWorldClient.java

@@ -51,7 +51,7 @@ public class HelloWorldClient {
 
   // OTel API
   Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.HelloWorldClient");;
+      OpenTelemetry.getTracer("io.opentelemetry.example.HelloWorldClient");;
   // Export traces as log
   LoggingSpanExporter exporter = new LoggingSpanExporter();
   // Share context via text headers

examples/grpc/src/main/java/io/opentelemetry/example/HelloWorldClientStream.java

@@ -54,7 +54,7 @@ public class HelloWorldClientStream {
 
   // OTel API
   Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.HelloWorldClient");;
+      OpenTelemetry.getTracer("io.opentelemetry.example.HelloWorldClient");;
   // Export traces as log
   LoggingSpanExporter exporter = new LoggingSpanExporter();
   // Share context via text headers

examples/grpc/src/main/java/io/opentelemetry/example/HelloWorldServer.java

@@ -49,7 +49,7 @@ public class HelloWorldServer {
 
   // OTel API
   Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.HelloWorldServer");
+      OpenTelemetry.getTracer("io.opentelemetry.example.HelloWorldServer");
   // Export traces as log
   LoggingSpanExporter exporter = new LoggingSpanExporter();
   // Share context via text

examples/http/src/main/java/io/opentelemetry/example/http/HttpClient.java

@@ -37,7 +37,7 @@ public class HttpClient {
 
   // OTel API
   private static Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.http.HttpClient");
+      OpenTelemetry.getTracer("io.opentelemetry.example.http.HttpClient");
   // Export traces to log
   private static LoggingSpanExporter loggingExporter = new LoggingSpanExporter();
   // Inject the span context into the request

examples/http/src/main/java/io/opentelemetry/example/http/HttpServer.java

@@ -28,7 +28,6 @@ import io.opentelemetry.exporters.logging.LoggingSpanExporter;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.trace.TracerSdkProvider;
 import io.opentelemetry.sdk.trace.export.SimpleSpansProcessor;
-import io.opentelemetry.trace.*;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.net.InetSocketAddress;
@@ -101,7 +100,7 @@ public class HttpServer {
 
   // OTel API
   private static Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.http.HttpServer");
+      OpenTelemetry.getTracer("io.opentelemetry.example.http.HttpServer");
   // Export traces to log
   private static LoggingSpanExporter loggingExporter = new LoggingSpanExporter();
   // Extract the context from http headers

examples/jaeger/src/main/java/io/opentelemetry/example/JaegerExample.java

@@ -16,7 +16,7 @@ public class JaegerExample {
 
   // OTel API
   private Tracer tracer =
-      OpenTelemetry.getTracerProvider().get("io.opentelemetry.example.JaegerExample");
+      OpenTelemetry.getTracer("io.opentelemetry.example.JaegerExample");
   // Export traces to Jaeger
   private JaegerGrpcSpanExporter jaegerExporter;
 

exporters/jaeger/src/test/java/io/opentelemetry/exporters/jaeger/JaegerIntegrationTest.java

@@ -49,8 +49,7 @@ public class JaegerIntegrationTest {
   private static final String JAEGER_VERSION = "1.17";
   private static final String SERVICE_NAME = "E2E-test";
   private static final String JAEGER_URL = "http://localhost";
-  private final Tracer tracer =
+  private final Tracer tracer = OpenTelemetry.getTracer(getClass().getCanonicalName());
-      OpenTelemetry.getTracerProvider().get(getClass().getCanonicalName());
 
   @SuppressWarnings("rawtypes")
   @ClassRule

opentracing_shim/src/test/java/io/opentelemetry/opentracingshim/TraceShimTest.java

@@ -31,7 +31,7 @@ public class TraceShimTest {
   @Test
   public void createTracerShim_default() {
     TracerShim tracerShim = (TracerShim) TraceShim.createTracerShim();
-    assertEquals(OpenTelemetry.getTracerProvider().get("opentracingshim"), tracerShim.tracer());
+    assertEquals(OpenTelemetry.getTracer("opentracingshim"), tracerShim.tracer());
     assertEquals(OpenTelemetry.getCorrelationContextManager(), tracerShim.contextManager());
   }
 

opentracing_shim/src/test/java/io/opentelemetry/opentracingshim/TracerShimTest.java

@@ -42,7 +42,7 @@ public class TracerShimTest {
     tracerShim =
         new TracerShim(
             new TelemetryInfo(
-                OpenTelemetry.getTracerProvider().get("opentracingshim"),
+                OpenTelemetry.getTracer("opentracingshim"),
                 OpenTelemetry.getCorrelationContextManager(),
                 OpenTelemetry.getPropagators()));
   }

sdk/src/main/java/io/opentelemetry/sdk/trace/export/BatchSpansProcessor.java

@@ -155,7 +155,7 @@ public final class BatchSpansProcessor implements SpanProcessor {
   private static final class Worker implements Runnable {
 
     static {
-      Meter meter = OpenTelemetry.getMeterProvider().get("io.opentelemetry.sdk.trace");
+      Meter meter = OpenTelemetry.getMeter("io.opentelemetry.sdk.trace");
       LongCounter droppedSpansCounter =
           meter
               .longCounterBuilder("droppedSpans")