1 files changed, 96 insertions, 0 deletions
diff --git a/api/src/main/java/io/opencensus/trace/export/SpanExporter.java b/api/src/main/java/io/opencensus/trace/export/SpanExporter.java
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+/*
+ * Copyright 2017, OpenCensus Authors
+ *
+ * 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
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.opencensus.trace.export;
+
+import io.opencensus.trace.Span;
+import io.opencensus.trace.TraceOptions;
+import java.util.Collection;
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * A service that is used by the library to export {@code SpanData} for all the spans that are part
+ * of a distributed sampled trace (see {@link TraceOptions#isSampled()}).
+ *
+ * @since 0.5
+ */
+@ThreadSafe
+public abstract class SpanExporter {
+  private static final SpanExporter NOOP_SPAN_EXPORTER = new NoopSpanExporter();
+
+  /**
+   * Returns the no-op implementation of the {@code ExportComponent}.
+   *
+   * @return the no-op implementation of the {@code ExportComponent}.
+   * @since 0.5
+   */
+  public static SpanExporter getNoopSpanExporter() {
+    return NOOP_SPAN_EXPORTER;
+  }
+
+  /**
+   * Registers a new service handler that is used by the library to export {@code SpanData} for
+   * sampled spans (see {@link TraceOptions#isSampled()}).
+   *
+   * @param name the name of the service handler. Must be unique for each service.
+   * @param handler the service handler that is called for each ended sampled span.
+   * @since 0.5
+   */
+  public abstract void registerHandler(String name, Handler handler);
+
+  /**
+   * Unregisters the service handler with the provided name.
+   *
+   * @param name the name of the service handler that will be unregistered.
+   * @since 0.5
+   */
+  public abstract void unregisterHandler(String name);
+
+  /**
+   * An abstract class that allows different tracing services to export recorded data for sampled
+   * spans in their own format.
+   *
+   * <p>To export data this MUST be register to to the ExportComponent using {@link
+   * #registerHandler(String, Handler)}.
+   *
+   * @since 0.5
+   */
+  public abstract static class Handler {
+
+    /**
+     * Exports a list of sampled (see {@link TraceOptions#isSampled()}) {@link Span}s using the
+     * immutable representation {@link SpanData}.
+     *
+     * <p>This may be called from a different thread than the one that called {@link Span#end()}.
+     *
+     * <p>Implementation SHOULD not block the calling thread. It should execute the export on a
+     * different thread if possible.
+     *
+     * @param spanDataList a list of {@code SpanData} objects to be exported.
+     * @since 0.5
+     */
+    public abstract void export(Collection<SpanData> spanDataList);
+  }
+
+  private static final class NoopSpanExporter extends SpanExporter {
+
+    @Override
+    public void registerHandler(String name, Handler handler) {}
+
+    @Override
+    public void unregisterHandler(String name) {}
+  }
+}