docs: adding pubsub emulator example

README.md

@@ -52,20 +52,20 @@ If you are using Maven without the BOM, add this to your dependencies:
 If you are using Gradle 5.x or later, add this to your dependencies:
 
 ```Groovy
-implementation platform('com.google.cloud:libraries-bom:26.15.0')
+implementation platform('com.google.cloud:libraries-bom:26.16.0')
 
 implementation 'com.google.cloud:google-cloud-pubsub'
 ```
 If you are using Gradle without BOM, add this to your dependencies:
 
 ```Groovy
-implementation 'com.google.cloud:google-cloud-pubsub:1.123.12'
+implementation 'com.google.cloud:google-cloud-pubsub:1.123.13'
 ```
 
 If you are using SBT, add this to your dependencies:
 
 ```Scala
-libraryDependencies += "com.google.cloud" % "google-cloud-pubsub" % "1.123.12"
+libraryDependencies += "com.google.cloud" % "google-cloud-pubsub" % "1.123.13"
 ```
 <!-- {x-version-update-end} -->
 
@@ -304,6 +304,7 @@ Samples are in the [`samples/`](https://github.com/googleapis/java-pubsub/tree/m
 | Test Topic Permissions Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/TestTopicPermissionsExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/TestTopicPermissionsExample.java) |
 | Update Dead Letter Policy Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/UpdateDeadLetterPolicyExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/UpdateDeadLetterPolicyExample.java) |
 | Update Push Configuration Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/UpdatePushConfigurationExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/UpdatePushConfigurationExample.java) |
+| Use Pub Sub Emulator Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/UsePubSubEmulatorExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/UsePubSubEmulatorExample.java) |
 | Update Topic Schema Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/UpdateTopicSchemaExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/UpdateTopicSchemaExample.java) |
 | State | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/utilities/State.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/utilities/State.java) |
 | State Proto | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/utilities/StateProto.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/utilities/StateProto.java) |

samples/snippets/src/main/java/pubsub/UsePubSubEmulatorExample.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2017 Google LLC
+ *
+ * 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 pubsub;
+
+import com.google.api.gax.core.CredentialsProvider;
+import com.google.api.gax.core.NoCredentialsProvider;
+import com.google.api.gax.grpc.GrpcTransportChannel;
+import com.google.api.gax.rpc.FixedTransportChannelProvider;
+import com.google.api.gax.rpc.TransportChannelProvider;
+import com.google.cloud.pubsub.v1.Publisher;
+import com.google.cloud.pubsub.v1.TopicAdminClient;
+import com.google.cloud.pubsub.v1.TopicAdminSettings;
+import com.google.pubsub.v1.TopicName;
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import java.io.IOException;
+
+/**
+ * Snippet that demonstrates creating Pub/Sub clients using the Google Cloud Pub/Sub emulator.
+ *
+ * <p>Note: clients cannot start/stop the emulator.
+ */
+public class UsePubSubEmulatorExample {
+
+  public static void main(String... args) throws IOException {
+    // [START pubsub_use_emulator]
+    String hostport = System.getenv("PUBSUB_EMULATOR_HOST");
+    ManagedChannel channel = ManagedChannelBuilder.forTarget(hostport).usePlaintext().build();
+    try {
+      TransportChannelProvider channelProvider =
+          FixedTransportChannelProvider.create(GrpcTransportChannel.create(channel));
+      CredentialsProvider credentialsProvider = NoCredentialsProvider.create();
+
+      // Set the channel and credentials provider when creating a `TopicAdminClient`.
+      // Similarly for SubscriptionAdminClient
+      TopicAdminClient topicClient =
+          TopicAdminClient.create(
+              TopicAdminSettings.newBuilder()
+                  .setTransportChannelProvider(channelProvider)
+                  .setCredentialsProvider(credentialsProvider)
+                  .build());
+
+      TopicName topicName = TopicName.of("my-project-id", "my-topic-id");
+      // Set the channel and credentials provider when creating a `Publisher`.
+      // Similarly for Subscriber
+      Publisher publisher =
+          Publisher.newBuilder(topicName)
+              .setChannelProvider(channelProvider)
+              .setCredentialsProvider(credentialsProvider)
+              .build();
+    } finally {
+      channel.shutdown();
+    }
+    // [END pubsub_use_emulator]
+  }
+}