docs(samples): Update Dataflow snippets to Beam 2.57 (#9392)

* docs(samples): Update Dataflow snippets for Beam 2.57

* Minor style fix: Remove unused local variable

Author: VeronicaWasson

dataflow/snippets/pom.xml

@@ -37,7 +37,7 @@
     <maven.compiler.source>11</maven.compiler.source>
     <maven.compiler.target>11</maven.compiler.target>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <apache_beam.version>2.56.0</apache_beam.version>
+    <apache_beam.version>2.57.0</apache_beam.version>
     <slf4j.version>2.0.12</slf4j.version>
     <parquet.version>1.14.0</parquet.version>
     <iceberg.version>1.4.2</iceberg.version>

dataflow/snippets/src/main/java/com/example/dataflow/ApacheIcebergRead.java

@@ -59,7 +59,7 @@ public static void main(String[] args) {
 
     // Parse the pipeline options passed into the application. Example:
     //   --runner=DirectRunner --warehouseLocation=$LOCATION --catalogName=$CATALOG \
-    //   -tableName= $TABLE_NAME --outputPath=$OUTPUT_FILE
+    //   --tableName= $TABLE_NAME --outputPath=$OUTPUT_FILE
     // For more information, see https://beam.apache.org/documentation/programming-guide/#configuring-pipeline-options
     Options options = PipelineOptionsFactory.fromArgs(args).withValidation().as(Options.class);
     Pipeline pipeline = Pipeline.create(options);
@@ -77,11 +77,8 @@ public static void main(String[] args) {
         .build();
 
     // Build the pipeline.
-    PCollectionRowTuple.empty(pipeline).apply(
-            Managed.read(Managed.ICEBERG)
-                .withConfig(config)
-        )
-        .get("output")
+    pipeline.apply(Managed.read(Managed.ICEBERG).withConfig(config))
+        .getSinglePCollection()
         // Format each record as a string with the format 'id:name'.
         .apply(MapElements
             .into(TypeDescriptors.strings())

dataflow/snippets/src/main/java/com/example/dataflow/ApacheIcebergWrite.java

@@ -85,14 +85,9 @@ public static void main(String[] args) {
         .build();
 
     // Build the pipeline.
-    var input = pipeline
-        .apply(Create.of(TABLE_ROWS))
-        .apply(JsonToRow.withSchema(SCHEMA));
-
-    PCollectionRowTuple.of("input", input).apply(
-        Managed.write(Managed.ICEBERG)
-            .withConfig(config)
-    );
+    pipeline.apply(Create.of(TABLE_ROWS))
+        .apply(JsonToRow.withSchema(SCHEMA))
+        .apply(Managed.write(Managed.ICEBERG).withConfig(config));
 
     pipeline.run().waitUntilFinish();
   }

dataflow/snippets/src/main/java/com/example/dataflow/PubSubWriteWithAttributes.java

@@ -70,7 +70,7 @@ public static void main(String[] args) {
     );
 
     // Parse the pipeline options passed into the application. Example:
-    //   ----runner=DirectRunner --topic=projects/MY_PROJECT/topics/MY_TOPIC"
+    //   --runner=DirectRunner --topic=projects/MY_PROJECT/topics/MY_TOPIC"
     // For more information, see https://beam.apache.org/documentation/programming-guide/#configuring-pipeline-options
     var options = PipelineOptionsFactory.fromArgs(args).withValidation().as(Options.class);
     var pipeline = Pipeline.create(options);