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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
    https://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.
/**
 * 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
 *
 *     https://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.avro.util.internal;

import java.io.IOException;

import org.apache.avro.JsonProperties;
import org.apache.avro.Schema;
import org.apache.avro.Schema.Field;
import org.apache.avro.Schema.Field.Order;
import org.apache.avro.io.Encoder;
import org.apache.avro.io.EncoderFactory;
import org.apache.avro.io.JsonEncoder;
import org.apache.avro.io.parsing.ResolvingGrammarGenerator;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonNode;

public class Accessor {
  public abstract static class JsonPropertiesAccessor {
    protected abstract void addProp(JsonProperties props, String name, JsonNode value);
  }

  public abstract static class FieldAccessor {
    protected abstract JsonNode defaultValue(Field field);

    protected abstract Field createField(String name, Schema schema, String doc, JsonNode defaultValue,
        boolean validate, Order order);

    protected abstract Field createField(String name, Schema schema, String doc, JsonNode defaultValue);
  }

  public abstract static class ResolvingGrammarGeneratorAccessor {
    protected abstract void encode(Encoder e, Schema s, JsonNode n) throws IOException;
  }

  public abstract static class EncoderFactoryAccessor {
    protected abstract JsonEncoder jsonEncoder(EncoderFactory factory, Schema schema, JsonGenerator gen)
        throws IOException;
  }

  private static volatile JsonPropertiesAccessor jsonPropertiesAccessor;

  private static volatile FieldAccessor fieldAccessor;

  private static volatile ResolvingGrammarGeneratorAccessor resolvingGrammarGeneratorAccessor;

  public static void setAccessor(JsonPropertiesAccessor accessor) {
    if (jsonPropertiesAccessor != null)
      throw new IllegalStateException("JsonPropertiesAccessor already initialized");
    jsonPropertiesAccessor = accessor;
  }

  public static void setAccessor(FieldAccessor accessor) {
    if (fieldAccessor != null)
      throw new IllegalStateException("FieldAccessor already initialized");
    fieldAccessor = accessor;
  }

  private static FieldAccessor fieldAccessor() {
    if (fieldAccessor == null)
      ensureLoaded(Field.class);
    return fieldAccessor;
  }

  public static void setAccessor(ResolvingGrammarGeneratorAccessor accessor) {
    if (resolvingGrammarGeneratorAccessor != null)
      throw new IllegalStateException("ResolvingGrammarGeneratorAccessor already initialized");
    resolvingGrammarGeneratorAccessor = accessor;
  }

  private static ResolvingGrammarGeneratorAccessor resolvingGrammarGeneratorAccessor() {
    if (resolvingGrammarGeneratorAccessor == null)
      ensureLoaded(ResolvingGrammarGenerator.class);
    return resolvingGrammarGeneratorAccessor;
  }

  private static void ensureLoaded(Class<?> c) {
    try {
      Class.forName(c.getName());
    } catch (ClassNotFoundException e) {
      // Shall never happen as the class is specified by its Class instance
    }
  }

  public static void addProp(JsonProperties props, String name, JsonNode value) {
    jsonPropertiesAccessor.addProp(props, name, value);
  }

  public static JsonNode defaultValue(Field field) {
    return fieldAccessor.defaultValue(field);
  }

  public static void encode(Encoder e, Schema s, JsonNode n) throws IOException {
    resolvingGrammarGeneratorAccessor().encode(e, s, n);
  }

  public static Field createField(String name, Schema schema, String doc, JsonNode defaultValue, boolean validate,
      Order order) {
    return fieldAccessor().createField(name, schema, doc, defaultValue, validate, order);
  }

  public static Field createField(String name, Schema schema, String doc, JsonNode defaultValue) {
    return fieldAccessor().createField(name, schema, doc, defaultValue);
  }

}