add javadocs to SpannerConfig

sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/SpannerConfig.java

@@ -148,82 +148,107 @@ abstract Builder setExecuteStreamingSqlRetrySettings(
     public abstract SpannerConfig build();
   }
 
+  /** Specifies the Cloud Spanner project ID */
   public SpannerConfig withProjectId(ValueProvider<String> projectId) {
     return toBuilder().setProjectId(projectId).build();
   }
 
+  /** Specifies the Cloud Spanner project ID */
   public SpannerConfig withProjectId(String projectId) {
     return withProjectId(ValueProvider.StaticValueProvider.of(projectId));
   }
 
+  /** Specifies the Cloud Spanner instance ID */
   public SpannerConfig withInstanceId(ValueProvider<String> instanceId) {
     return toBuilder().setInstanceId(instanceId).build();
   }
 
+  /** Specifies the Cloud Spanner instance ID */
   public SpannerConfig withInstanceId(String instanceId) {
     return withInstanceId(ValueProvider.StaticValueProvider.of(instanceId));
   }
 
+  /** Specifies the Cloud Spanner database ID */
   public SpannerConfig withDatabaseId(ValueProvider<String> databaseId) {
     return toBuilder().setDatabaseId(databaseId).build();
   }
 
+  /** Specifies the Cloud Spanner database ID */
   public SpannerConfig withDatabaseId(String databaseId) {
     return withDatabaseId(ValueProvider.StaticValueProvider.of(databaseId));
   }
 
+  /** Specifies the Cloud Spanner host */
   public SpannerConfig withHost(ValueProvider<String> host) {
     return toBuilder().setHost(host).build();
   }
 
+  /** Specifies the Cloud Spanner host, when an emulator is used */
   public SpannerConfig withEmulatorHost(ValueProvider<String> emulatorHost) {
     return toBuilder().setEmulatorHost(emulatorHost).build();
   }
 
+  /**
+   * Specifies whether a local channel provider should be used. This should be set to True when an
+   * emulator is used.
+   */
   public SpannerConfig withIsLocalChannelProvider(ValueProvider<Boolean> isLocalChannelProvider) {
     return toBuilder().setIsLocalChannelProvider(isLocalChannelProvider).build();
   }
 
+  /** Specifies the commit deadline. This is overridden if the CommitRetrySettings is specified. */
   public SpannerConfig withCommitDeadline(Duration commitDeadline) {
     return withCommitDeadline(ValueProvider.StaticValueProvider.of(commitDeadline));
   }
 
+  /** Specifies the commit deadline. This is overridden if the CommitRetrySettings is specified. */
   public SpannerConfig withCommitDeadline(ValueProvider<Duration> commitDeadline) {
     return toBuilder().setCommitDeadline(commitDeadline).build();
   }
 
+  /** Specifies the maximum cumulative backoff. */
   public SpannerConfig withMaxCumulativeBackoff(Duration maxCumulativeBackoff) {
     return withMaxCumulativeBackoff(ValueProvider.StaticValueProvider.of(maxCumulativeBackoff));
   }
 
+  /** Specifies the maximum cumulative backoff. */
   public SpannerConfig withMaxCumulativeBackoff(ValueProvider<Duration> maxCumulativeBackoff) {
     return toBuilder().setMaxCumulativeBackoff(maxCumulativeBackoff).build();
   }
 
+  /**
+   * Specifies the ExecuteStreamingSql retry settings. If not set, the default timeout is set to 2
+   * hours.
+   */
   public SpannerConfig withExecuteStreamingSqlRetrySettings(
       RetrySettings executeStreamingSqlRetrySettings) {
     return toBuilder()
         .setExecuteStreamingSqlRetrySettings(executeStreamingSqlRetrySettings)
         .build();
   }
 
+  /** Specifies the commit retry settings. Setting this overrides the commit deadline. */
   public SpannerConfig withCommitRetrySettings(RetrySettings commitRetrySettings) {
     return toBuilder().setCommitRetrySettings(commitRetrySettings).build();
   }
 
+  /** Specifies the errors that will be retried by the client library for all operations. */
   public SpannerConfig withRetryableCodes(ImmutableSet<Code> retryableCodes) {
     return toBuilder().setRetryableCodes(retryableCodes).build();
   }
 
+  /** Specifies the service factory to create instance of Spanner. */
   @VisibleForTesting
   SpannerConfig withServiceFactory(ServiceFactory<Spanner, SpannerOptions> serviceFactory) {
     return toBuilder().setServiceFactory(serviceFactory).build();
   }
 
+  /** Specifies the RPC priority. */
   public SpannerConfig withRpcPriority(RpcPriority rpcPriority) {
     return withRpcPriority(ValueProvider.StaticValueProvider.of(rpcPriority));
   }
 
+  /** Specifies the RPC priority. */
   public SpannerConfig withRpcPriority(ValueProvider<RpcPriority> rpcPriority) {
     return toBuilder().setRpcPriority(rpcPriority).build();
   }