Move Dynatrace metrics exporter for API v1 to a separate package

implementations/micrometer-registry-dynatrace/src/main/java/io/micrometer/dynatrace/AbstractDynatraceExporter.java

@@ -0,0 +1,47 @@
+/**
+ * Copyright 2021 VMware, Inc.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.dynatrace;
+
+import io.micrometer.core.instrument.Clock;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.ipc.http.HttpSender;
+
+import javax.annotation.Nonnull;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Base class for implementations of Dynatrace exporters.
+ *
+ * @author Georg Pirklbauer
+ */
+public abstract class AbstractDynatraceExporter {
+
+    protected DynatraceConfig config;
+    protected Clock clock;
+    protected HttpSender httpClient;
+
+    public abstract void export(@Nonnull MeterRegistry registry);
+
+    public TimeUnit getBaseTimeUnit() {
+        return TimeUnit.MILLISECONDS;
+    }
+
+    public AbstractDynatraceExporter(DynatraceConfig config, Clock clock, HttpSender httpClient) {
+        this.config = config;
+        this.clock = clock;
+        this.httpClient = httpClient;
+    }
+}

implementations/micrometer-registry-dynatrace/src/main/java/io/micrometer/dynatrace/DynatraceApiVersion.java

@@ -0,0 +1,24 @@
+/**
+ * Copyright 2021 VMware, Inc.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.micrometer.dynatrace;
+
+/**
+ * An enum containing valid Dynatrace API versions.
+ */
+public enum DynatraceApiVersion {
+    V1,
+}

implementations/micrometer-registry-dynatrace/src/main/java/io/micrometer/dynatrace/DynatraceConfig.java

@@ -27,6 +27,7 @@
  * Configuration for {@link DynatraceMeterRegistry}
  *
  * @author Oriol Barcelona
+ * @author Georg Pirklbauer
  */
 public interface DynatraceConfig extends StepRegistryConfig {
 
@@ -49,7 +50,7 @@ default String deviceId() {
 
     default String technologyType() {
         return getSecret(this, "technologyType")
-                .map(v -> StringUtils.isEmpty(v) ? "java" : v)
+                .map(val -> StringUtils.isEmpty(val) ? "java" : val)
                 .get();
     }
 
@@ -64,8 +65,28 @@ default String group() {
         return get(prefix() + ".group");
     }
 
+    /**
+     * Return the version of the target Dynatrace API.
+     *
+     * @return a {@link DynatraceApiVersion} containing the version of the targeted Dynatrace API.
+     */
+    default DynatraceApiVersion apiVersion() {
+        // if not specified, defaults to v1 for backwards compatibility.
+        return getEnum(this, DynatraceApiVersion.class, "apiVersion")
+                .orElse(DynatraceApiVersion.V1);
+    }
+
     @Override
     default Validated<?> validate() {
+        Validated<DynatraceApiVersion> apiVersionValidation = checkRequired("apiVersion", DynatraceConfig::apiVersion).apply(this);
+        if (apiVersionValidation.isInvalid()) {
+            return apiVersionValidation;
+        }
+
+        return validateV1();
+    }
+
+    default Validated<?> validateV1() {
         return checkAll(this,
                 c -> StepRegistryConfig.validate(c),
                 checkRequired("apiToken", DynatraceConfig::apiToken),