content: /*
   * 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.schemas.transforms.providers;
  
  import com.google.auto.service.AutoService;
  import com.google.auto.value.AutoValue;
  import java.net.MalformedURLException;
  import java.util.Collections;
  import java.util.List;
  import javax.annotation.Nullable;
  import org.apache.beam.sdk.schemas.AutoValueSchema;
  import org.apache.beam.sdk.schemas.Schema;
  import org.apache.beam.sdk.schemas.annotations.DefaultSchema;
  import org.apache.beam.sdk.schemas.transforms.SchemaTransform;
  import org.apache.beam.sdk.schemas.transforms.SchemaTransformProvider;
  import org.apache.beam.sdk.schemas.transforms.TypedSchemaTransformProvider;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.transforms.ParDo;
  import org.apache.beam.sdk.values.PCollectionRowTuple;
  import org.apache.beam.sdk.values.PCollectionTuple;
  import org.apache.beam.sdk.values.Row;
  import org.apache.beam.sdk.values.TupleTag;
  import org.apache.beam.sdk.values.TupleTagList;
  
  /**
   * An implementation of {@link TypedSchemaTransformProvider} for Filter for the java language.
   *
   * <p><b>Internal only:</b> This class is actively being worked on, and it will likely change. We
   * provide no backwards compatibility guarantees, and it should not be implemented outside the Beam
   * repository.
   */
  @SuppressWarnings({
    "nullness" // TODO(https://github.com/apache/beam/issues/20497)
  })
  @AutoService(SchemaTransformProvider.class)
  public class JavaFilterTransformProvider
      extends TypedSchemaTransformProvider<JavaFilterTransformProvider.Configuration> {
    protected static final String INPUT_ROWS_TAG = "input";
    protected static final String OUTPUT_ROWS_TAG = "output";
  
    @Override
    protected Class<Configuration> configurationClass() {
      return Configuration.class;
    }
  
    @Override
    protected SchemaTransform from(Configuration configuration) {
      return new JavaFilterTransform(configuration);
    }
  
    @Override
    public String identifier() {
      return "beam:schematransform:org.apache.beam:yaml:filter-java:v1";
    }
  
    @Override
    public List<String> inputCollectionNames() {
      return Collections.singletonList(INPUT_ROWS_TAG);
    }
  
    @Override
    public List<String> outputCollectionNames() {
      return Collections.singletonList(OUTPUT_ROWS_TAG);
    }
  
    @DefaultSchema(AutoValueSchema.class)
    @AutoValue
    public abstract static class Configuration {
      @Nullable
      public abstract String getLanguage();
  
      public abstract JavaRowUdf.Configuration getKeep();
  
      @Nullable
      public abstract ErrorHandling getErrorHandling();
  
      public static Builder builder() {
        return new AutoValue_JavaFilterTransformProvider_Configuration.Builder();
      }
  
      @AutoValue.Builder
      public abstract static class Builder {
  
        public abstract Builder setLanguage(String language);
  
        public abstract Builder setKeep(JavaRowUdf.Configuration keep);
  
        public abstract Builder setErrorHandling(ErrorHandling errorHandling);
  
        public abstract Configuration build();
      }
    }
  
    /** A {@link SchemaTransform} for Filter-java. */
    protected static class JavaFilterTransform extends SchemaTransform {
  
      private final Configuration configuration;
  
      JavaFilterTransform(Configuration configuration) {
        this.configuration = configuration;
      }
  
      @Override
      public PCollectionRowTuple expand(PCollectionRowTuple input) {
        Schema inputSchema = input.get(INPUT_ROWS_TAG).getSchema();
        JavaRowUdf keepFn;
        try {
          keepFn = new JavaRowUdf(this.configuration.getKeep(), inputSchema);
        } catch (MalformedURLException
            | ReflectiveOperationException
            | StringCompiler.CompileException exn) {
          throw new RuntimeException(exn);
        }
        if (!keepFn.getOutputType().withNullable(false).equals(Schema.FieldType.BOOLEAN)) {
          throw new RuntimeException(
              String.format(
                  "KeepFn %s must return a boolean, but returns %s instead.",
                  this.configuration.getKeep(), keepFn.getOutputType()));
        }
        boolean handleErrors = ErrorHandling.hasOutput(configuration.getErrorHandling());
        Schema errorSchema = ErrorHandling.errorSchema(inputSchema);
  
        PCollectionTuple pcolls =
            input
                .get(INPUT_ROWS_TAG)
                .apply(
                    "Filter",
                    ParDo.of(createDoFn(keepFn, errorSchema, handleErrors))
                        .withOutputTags(filteredValues, TupleTagList.of(errorValues)));
        pcolls.get(filteredValues).setRowSchema(inputSchema);
        pcolls.get(errorValues).setRowSchema(errorSchema);
  
        PCollectionRowTuple result =
            PCollectionRowTuple.of(OUTPUT_ROWS_TAG, pcolls.get(filteredValues));
        if (handleErrors) {
          result = result.and(configuration.getErrorHandling().getOutput(), pcolls.get(errorValues));
        }
        return result;
      }
  
      private static final TupleTag<Row> filteredValues = new TupleTag<Row>() {};
      private static final TupleTag<Row> errorValues = new TupleTag<Row>() {};
  
      private static DoFn<Row, Row> createDoFn(
          JavaRowUdf keepFn, Schema errorSchema, boolean handleErrors) {
        return new DoFn<Row, Row>() {
          @ProcessElement
          public void processElement(@Element Row inputRow, MultiOutputReceiver out) {
            boolean keep = false;
            try {
              keep = (boolean) keepFn.getFunction().apply(inputRow);
            } catch (Exception exn) {
              if (handleErrors) {
                out.get(errorValues).output(ErrorHandling.errorRecord(errorSchema, inputRow, exn));
              } else {
                throw new RuntimeException(exn);
              }
            }
            if (keep) {
              out.get(filteredValues).output(inputRow);
            }
          }
        };
      }
    }
  }
  