/*
 * 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;

import org.apache.beam.sdk.annotations.Experimental;
import org.apache.beam.sdk.annotations.Experimental.Kind;
import org.apache.beam.sdk.schemas.utils.POJOUtils;
import org.apache.beam.sdk.schemas.utils.PojoValueGetterFactory;
import org.apache.beam.sdk.schemas.utils.PojoValueSetterFactory;
import org.apache.beam.sdk.values.TypeDescriptor;

/**
 * A {@link SchemaProvider} for Java POJO objects.
 *
 * <p>This provider finds all public fields (recursively) in a Java object, and creates schemas and
 * rows that bind to those fields. The field order in the schema is not guaranteed to match the
 * field order in the class. The Java object is expected to have implemented a correct .equals() and
 * .hashCode() methods. The equals method must be completely determined by the schema fields. i.e.
 * if the object has hidden fields that are not reflected in the schema but are compared in equals,
 * then results will be incorrect.
 *
 * <p>TODO: Validate equals() method is provided, and if not generate a "slow" equals method based
 * on the schema.
 */
@Experimental(Kind.SCHEMAS)
public class JavaFieldSchema extends GetterBasedSchemaProvider {
  @Override
  public <T> Schema schemaFor(TypeDescriptor<T> typeDescriptor) {
    return POJOUtils.schemaFromPojoClass(typeDescriptor.getRawType());
  }

  @Override
  public FieldValueGetterFactory fieldValueGetterFactory() {
    return new PojoValueGetterFactory();
  }

  @Override
  public FieldValueSetterFactory fieldValueSetterFactory() {
    return new PojoValueSetterFactory();
  }
}
