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.logicaltypes;
  
  import static org.apache.beam.sdk.util.Preconditions.checkArgumentNotNull;
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkArgument;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.Map;
  import java.util.Objects;
  import java.util.stream.Collectors;
  import org.apache.beam.sdk.schemas.Schema;
  import org.apache.beam.sdk.schemas.Schema.Field;
  import org.apache.beam.sdk.schemas.Schema.FieldType;
  import org.apache.beam.sdk.schemas.Schema.LogicalType;
  import org.apache.beam.sdk.schemas.SchemaTranslation;
  import org.apache.beam.sdk.values.Row;
  import org.checkerframework.checker.nullness.qual.NonNull;
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * A logical type representing a union of fields. This logical type is initialized with a set of
   * field and represents a union of those fields. This logical type is backed by a Row object
   * containing one nullable field matching each input field, and one additional {@link
   * EnumerationType} logical type field that indicates which field is set.
   */
  public class OneOfType implements LogicalType<OneOfType.Value, Row> {
    public static final String IDENTIFIER = "OneOf";
  
    private final Schema oneOfSchema;
    private final EnumerationType enumerationType;
    private final byte[] schemaProtoRepresentation;
  
    private OneOfType(List<Field> fields) {
      this(fields, null);
    }
  
    private OneOfType(List<Field> fields, @Nullable Map<String, Integer> enumMap) {
      List<Field> nullableFields =
          fields.stream().map(f -> f.withNullable(true)).collect(Collectors.toList());
      if (enumMap != null) {
        nullableFields.stream().forEach(f -> checkArgument(enumMap.containsKey(f.getName())));
        enumerationType = EnumerationType.create(enumMap);
      } else {
        List<String> enumValues =
            nullableFields.stream().map(Field::getName).collect(Collectors.toList());
        enumerationType = EnumerationType.create(enumValues);
      }
      oneOfSchema = Schema.builder().addFields(nullableFields).build();
      schemaProtoRepresentation =
          SchemaTranslation.schemaToProto(oneOfSchema, false, false).toByteArray();
    }
  
    /** Create an {@link OneOfType} logical type. */
    public static OneOfType create(Field... fields) {
      return create(Arrays.asList(fields));
    }
  
    /** Create an {@link OneOfType} logical type. */
    public static OneOfType create(List<Field> fields) {
      return new OneOfType(fields);
    }
  
    /**
     * Create an {@link OneOfType} logical type. This method allows control over the integer values in
     * the generated enum.
     */
    public static OneOfType create(List<Field> fields, Map<String, Integer> enumValues) {
      return new OneOfType(fields, enumValues);
    }
  
    /** Returns the schema of the underlying {@link Row} that is used to represent the union. */
    public Schema getOneOfSchema() {
      return oneOfSchema;
    }
  
    /** Returns the {@link EnumerationType} that is used to represent the case type. */
    public EnumerationType getCaseEnumType() {
      return enumerationType;
    }
  
    @Override
    public String getIdentifier() {
      return IDENTIFIER;
    }
  
    @Override
    public FieldType getArgumentType() {
      return FieldType.BYTES;
    }
  
    @Override
    public byte[] getArgument() {
      return schemaProtoRepresentation;
    }
  
    @Override
    public FieldType getBaseType() {
      return FieldType.row(oneOfSchema);
    }
  
    /** Create a {@link Value} specifying which field to set and the value to set. */
    public <T extends @NonNull Object> Value createValue(String caseValue, T value) {
      return createValue(getCaseEnumType().valueOf(caseValue), value);
    }
  
    /** Create a {@link Value} specifying which field to set and the value to set. */
    public <T extends @NonNull Object> Value createValue(int caseValue, T value) {
      return createValue(getCaseEnumType().valueOf(caseValue), value);
    }
  
    /** Create a {@link Value} specifying which field to set and the value to set. */
    public <T extends @NonNull Object> Value createValue(EnumerationType.Value caseType, T value) {
      return new Value(caseType, value);
    }
  
    public FieldType getFieldType(OneOfType.Value oneOneValue) {
      return oneOfSchema.getField(enumerationType.toString(oneOneValue.getCaseType())).getType();
    }
  
    @Override
    public Row toBaseType(Value input) {
      EnumerationType.Value caseType = input.getCaseType();
      int setFieldIndex = oneOfSchema.indexOf(enumerationType.toString(caseType));
      Row.Builder builder = Row.withSchema(oneOfSchema);
      for (int i = 0; i < oneOfSchema.getFieldCount(); ++i) {
        Object value = (i == setFieldIndex) ? input.getValue() : null;
        builder = builder.addValue(value);
      }
      return builder.build();
    }
  
    @Override
    public Value toInputType(Row base) {
      EnumerationType.Value caseType = null;
      Object oneOfValue = null;
      for (int i = 0; i < base.getFieldCount(); ++i) {
        Object value = base.getValue(i);
        if (value != null) {
          checkArgument(caseType == null, "More than one field set in union %s", this);
          caseType = enumerationType.valueOf(oneOfSchema.getField(i).getName());
          oneOfValue = value;
        }
      }
      checkArgumentNotNull(caseType, "No value set in union %s", this);
      checkArgumentNotNull(oneOfValue, "No value set in union %s", this);
      return createValue(caseType, oneOfValue);
    }
  
    @Override
    public String toString() {
      return "OneOf: " + oneOfSchema;
    }
  
    /**
     * Represents a single OneOf value. Each object contains an {@link EnumerationType.Value}
     * specifying which field is set along with the value of that field.
     */
    public static class Value {
      private final EnumerationType.Value caseType;
      private final Object value;
  
      public Value(EnumerationType.Value caseType, Object value) {
        this.caseType = caseType;
        this.value = value;
      }
  
      /** Returns the enumeration that specified which OneOf field is set. */
      public EnumerationType.Value getCaseType() {
        return caseType;
      }
  
      /** Returns the current value of the OneOf as the destination type. */
      public <T> T getValue(Class<T> clazz) {
        return (T) value;
      }
  
      /** Returns the current value of the OneOf. */
      public Object getValue() {
        return value;
      }
  
      @Override
      public String toString() {
        return "caseType: " + caseType + " Value: " + value;
      }
  
      @Override
      public boolean equals(@Nullable Object o) {
        if (this == o) {
          return true;
        }
        if (o == null || getClass() != o.getClass()) {
          return false;
        }
        Value value1 = (Value) o;
        return Objects.equals(caseType, value1.caseType) && Objects.equals(value, value1.value);
      }
  
      @Override
      public int hashCode() {
        return Objects.hash(caseType, value);
      }
    }
  }
  