[BEAM-12883] Add coder for ReadableFileCoder that supports MetadataCoderV2

sdks/java/core/src/main/java/org/apache/beam/sdk/io/ReadableFileCoder.java

@@ -20,31 +20,66 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import org.apache.beam.sdk.coders.AtomicCoder;
+import java.util.Collections;
+import java.util.List;
 import org.apache.beam.sdk.coders.Coder;
+import org.apache.beam.sdk.coders.CoderException;
+import org.apache.beam.sdk.coders.StructuredCoder;
 import org.apache.beam.sdk.coders.VarIntCoder;
 import org.apache.beam.sdk.io.fs.MatchResult;
+import org.apache.beam.sdk.io.fs.MatchResult.Metadata;
 import org.apache.beam.sdk.io.fs.MetadataCoder;
+import org.checkerframework.checker.initialization.qual.Initialized;
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.UnknownKeyFor;
 
-/** A {@link Coder} for {@link FileIO.ReadableFile}. */
-public class ReadableFileCoder extends AtomicCoder<FileIO.ReadableFile> {
-  private static final ReadableFileCoder INSTANCE = new ReadableFileCoder();
+/** A {@link Coder} for {@link org.apache.beam.sdk.io.FileIO.ReadableFile}. */
+public class ReadableFileCoder extends StructuredCoder<FileIO.ReadableFile> {
+
+  private final Coder<Metadata> metadataCoder;
+
+  public static ReadableFileCoder of(Coder<Metadata> metadataCoder) {
+    return new ReadableFileCoder(metadataCoder);
+  }
 
-  /** Returns the instance of {@link ReadableFileCoder}. */
   public static ReadableFileCoder of() {
-    return INSTANCE;
+    return new ReadableFileCoder(MetadataCoder.of());
+  }
+
+  public Coder<Metadata> getMetadataCoder() {
+    return metadataCoder;
+  }
+
+  private ReadableFileCoder(Coder<Metadata> metadataCoder) {
+    this.metadataCoder = metadataCoder;
   }
 
   @Override
-  public void encode(FileIO.ReadableFile value, OutputStream os) throws IOException {
-    MetadataCoder.of().encode(value.getMetadata(), os);
-    VarIntCoder.of().encode(value.getCompression().ordinal(), os);
+  public void encode(
+      FileIO.ReadableFile value, @UnknownKeyFor @NonNull @Initialized OutputStream outStream)
+      throws CoderException, IOException {
+    getMetadataCoder().encode(value.getMetadata(), outStream);
+    VarIntCoder.of().encode(value.getCompression().ordinal(), outStream);
   }
 
   @Override
-  public FileIO.ReadableFile decode(InputStream is) throws IOException {
-    MatchResult.Metadata metadata = MetadataCoder.of().decode(is);
-    Compression compression = Compression.values()[VarIntCoder.of().decode(is)];
+  public FileIO.ReadableFile decode(@UnknownKeyFor @NonNull @Initialized InputStream inStream)
+      throws CoderException, IOException {
+    MatchResult.Metadata metadata = getMetadataCoder().decode(inStream);
+    Compression compression = Compression.values()[VarIntCoder.of().decode(inStream)];
     return new FileIO.ReadableFile(metadata, compression);
   }
+
+  @Override
+  public @UnknownKeyFor @NonNull @Initialized List<? extends Coder<?>> getCoderArguments() {
+    return Collections.singletonList(metadataCoder);
+  }
+
+  @Override
+  public void verifyDeterministic() throws NonDeterministicException {
+    // ignore the default Metadata coder for backward compatible
+    if (!getMetadataCoder().equals(MetadataCoder.of())) {
+      verifyDeterministic(this, "Metadata coder must be deterministic", getMetadataCoder());
+    }
+  }
 }