fix: make awaitTermination and shutdown protected, since we already have close() method, it is confusing to have 3 shutdown methods (#330)

Author: yirutang

google-cloud-bigquerystorage/clirr-ignored-differences.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- see http://www.mojohaus.org/clirr-maven-plugin/examples/ignored-differences.html -->
+<differences>
+    <!--TODO: To be removed-->
+    <difference>
+        <differenceType>7009</differenceType>
+        <className>com/google/cloud/bigquery/storage/v1alpha2/StreamWriter</className>
+        <method>void shutdown()</method>
+    </difference>
+    <difference>
+        <differenceType>7009</differenceType>
+        <className>com/google/cloud/bigquery/storage/v1alpha2/StreamWriter</className>
+        <method>boolean awaitTermination(long, java.util.concurrent.TimeUnit) </method>
+    </difference>
+</differences>

google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1alpha2/StreamWriter.java

@@ -164,14 +164,10 @@ private StreamWriter(Builder builder)
         Instant.ofEpochSecond(
             stream.getCreateTime().getSeconds(), stream.getCreateTime().getNanos());
     if (stream.getType() == Stream.WriteStream.Type.PENDING && stream.hasCommitTime()) {
-      backgroundResources.shutdown();
-      backgroundResources.awaitTermination(1, TimeUnit.MINUTES);
       throw new IllegalStateException(
           "Cannot write to a stream that is already committed: " + streamName);
     }
     if (createTime.plus(streamTTL).compareTo(Instant.now()) < 0) {
-      backgroundResources.shutdown();
-      backgroundResources.awaitTermination(1, TimeUnit.MINUTES);
       throw new IllegalStateException(
           "Cannot write to a stream that is already expired: " + streamName);
     }
@@ -360,7 +356,7 @@ private void writeBatch(final InflightBatch inflightBatch) {
   /** Close the stream writer. Shut down all resources. */
   @Override
   public void close() {
-    LOG.info("Closing stream writer");
+    LOG.info("Closing stream writer:" + streamName);
     shutdown();
     try {
       awaitTermination(1, TimeUnit.MINUTES);
@@ -512,10 +508,12 @@ public RetrySettings getRetrySettings() {
    * should be invoked prior to deleting the {@link WriteStream} object in order to ensure that no
    * pending messages are lost.
    */
-  public void shutdown() {
-    Preconditions.checkState(
-        !shutdown.getAndSet(true), "Cannot shut down a writer already shut-down.");
-    LOG.info("Shutdown called on writer");
+  protected void shutdown() {
+    if (shutdown.getAndSet(true)) {
+      LOG.fine("Already shutdown.");
+      return;
+    }
+    LOG.fine("Shutdown called on writer");
     if (currentAlarmFuture != null && activeAlarm.getAndSet(false)) {
       currentAlarmFuture.cancel(false);
     }
@@ -535,7 +533,7 @@ public void shutdown() {
    *
    * <p>Call this method to make sure all resources are freed properly.
    */
-  public boolean awaitTermination(long duration, TimeUnit unit) throws InterruptedException {
+  protected boolean awaitTermination(long duration, TimeUnit unit) throws InterruptedException {
     return backgroundResources.awaitTermination(duration, unit);
   }
 

google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1alpha2/StreamWriterTest.java

@@ -294,8 +294,7 @@ public void testWriteByShutdown() throws Exception {
     // Note we are not advancing time or reaching the count threshold but messages should
     // still get written by call to shutdown
 
-    writer.shutdown();
-    writer.awaitTermination(10, TimeUnit.SECONDS);
+    writer.close();
 
     // Verify the appends completed
     assertTrue(appendFuture1.isDone());
@@ -407,8 +406,7 @@ public void run() {
     // Wait is necessary for response to be scheduled before timer is advanced.
     fakeExecutor.advanceTime(Duration.ofSeconds(10));
     t.join();
-    writer.shutdown();
-    writer.awaitTermination(1, TimeUnit.MINUTES);
+    writer.close();
   }
 
   @Test
@@ -527,8 +525,7 @@ public void testStreamReconnectionExceedRetry() throws Exception {
     } catch (ExecutionException e) {
       assertEquals(transientError.toString(), e.getCause().getCause().toString());
     }
-    writer.shutdown();
-    assertTrue(writer.awaitTermination(1, TimeUnit.MINUTES));
+    writer.close();
   }
 
   @Test
@@ -643,7 +640,7 @@ public void testWriterGetters() throws Exception {
             .getFlowControlSettings()
             .getMaxOutstandingRequestBytes()
             .longValue());
-    writer.shutdown();
+    writer.close();
   }
 
   @Test
@@ -823,29 +820,6 @@ public void testBuilderInvalidArguments() {
     }
   }
 
-  @Test
-  public void testAwaitTermination() throws Exception {
-    StreamWriter writer =
-        getTestStreamWriterBuilder("projects/p/datasets/d/tables/t/streams/await").build();
-    testBigQueryWrite.addResponse(AppendRowsResponse.newBuilder().build());
-    ApiFuture<AppendRowsResponse> appendFuture1 = sendTestMessage(writer, new String[] {"AWAIT"});
-    writer.shutdown();
-    assertTrue(writer.awaitTermination(1, TimeUnit.MINUTES));
-  }
-
-  @Test
-  public void testClose() throws Exception {
-    StreamWriter writer = getTestStreamWriterBuilder().build();
-    writer.close();
-    try {
-      writer.shutdown();
-      fail("Should throw");
-    } catch (IllegalStateException e) {
-      LOG.info(e.toString());
-      assertEquals("Cannot shut down a writer already shut-down.", e.getMessage());
-    }
-  }
-
   @Test
   public void testExistingClient() throws Exception {
     BigQueryWriteSettings settings =