created CsvIOReadFiles class (#31738)

Co-authored-by: Lahari Guduru <lahariguduru@google.com>

sdks/java/io/csv/src/main/java/org/apache/beam/sdk/io/csv/CsvIOReadFiles.java

@@ -0,0 +1,54 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.beam.sdk.io.csv;
+
+import org.apache.beam.sdk.Pipeline;
+import org.apache.beam.sdk.io.FileIO;
+import org.apache.beam.sdk.transforms.PTransform;
+import org.apache.beam.sdk.values.PCollection;
+import org.apache.beam.sdk.values.PCollectionTuple;
+import org.apache.beam.sdk.values.TupleTag;
+
+/**
+ * Skeleton for error handling in CsvIO that transforms a {@link FileIO.ReadableFile} into the
+ * result of parsing.
+ */
+// TODO(https://github.com/apache/beam/issues/31736): Plan completion in future PR after
+// dependencies are completed.
+class CsvIOReadFiles<T> extends PTransform<PCollection<FileIO.ReadableFile>, CsvIOParseResult<T>> {
+  /** Stores required parameters for parsing. */
+  private final CsvIOParseConfiguration.Builder configBuilder;
+
+  CsvIOReadFiles(CsvIOParseConfiguration.Builder configBuilder) {
+    this.configBuilder = configBuilder;
+  }
+
+  /** {@link PTransform} that parses and relays the filename associated with each error. */
+  // TODO: complete expand method to unsure parsing from FileIO.ReadableFile to CsvIOParseResult.
+  @Override
+  public CsvIOParseResult<T> expand(PCollection<FileIO.ReadableFile> input) {
+    // TODO(https://github.com/apache/beam/issues/31736): Needed to prevent check errors, will
+    // remove with future PR.
+    configBuilder.build();
+    TupleTag<T> outputTag = new TupleTag<>();
+    TupleTag<CsvIOParseError> errorTag = new TupleTag<>();
+    Pipeline p = input.getPipeline();
+    PCollectionTuple tuple = PCollectionTuple.empty(p);
+    return CsvIOParseResult.of(outputTag, errorTag, tuple);
+  }
+}

sdks/java/io/csv/src/test/java/org/apache/beam/sdk/io/csv/CsvIOReadFilesTest.java

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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.beam.sdk.io.csv;
+
+import org.apache.beam.sdk.util.SerializableUtils;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link CsvIOReadFiles}. */
+@RunWith(JUnit4.class)
+public class CsvIOReadFilesTest {
+  @Test
+  public void isSerializable() {
+    SerializableUtils.ensureSerializable(CsvIOReadFiles.class);
+  }
+}