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/*
 * Copyright (C) 2014 Square, Inc.
 *
 * Licensed 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 io.avaje.json.core;

import io.avaje.json.JsonAdapter;
import io.avaje.json.JsonReader;
import io.avaje.json.JsonWriter;
import io.avaje.json.view.ViewBuilder;
import io.avaje.json.view.ViewBuilderAware;

import java.lang.invoke.MethodHandle;
import java.util.*;

/**
 * Converts collection types to JSON arrays containing their converted contents.
 */
abstract class CollectionAdapter, T> implements ViewBuilderAware, JsonAdapter {

  static  JsonAdapter> createList(JsonAdapter elementAdapter) {
    return new CollectionAdapter<>(elementAdapter) {
      @Override
      List newCollection() {
        return new ArrayList<>();
      }
    };
  }

  static  JsonAdapter> createSet(JsonAdapter elementAdapter) {
    return new CollectionAdapter<>(elementAdapter) {
      @Override
      Set newCollection() {
        return new LinkedHashSet<>();
      }
    };
  }

  private final JsonAdapter elementAdapter;

  private CollectionAdapter(JsonAdapter elementAdapter) {
    this.elementAdapter = elementAdapter;
  }

  abstract C newCollection();

  @Override
  public boolean isViewBuilderAware() {
    return elementAdapter.isViewBuilderAware();
  }

  @Override
  public ViewBuilderAware viewBuild() {
    return this;
  }

  @Override
  public void build(ViewBuilder builder, String name, MethodHandle handle) {
    builder.addArray(name, elementAdapter, handle);
  }

  @Override
  public C fromJson(JsonReader reader) {
    C result = newCollection();
    reader.beginArray();
    while (reader.hasNextElement()) {
      result.add(elementAdapter.fromJson(reader));
    }
    reader.endArray();
    return result;
  }

  @Override
  public void toJson(JsonWriter writer, C value) {
    if (value.isEmpty()) {
      writer.emptyArray();
      return;
    }
    writer.beginArray();
    for (T element : value) {
      elementAdapter.toJson(writer, element);
    }
    writer.endArray();
  }

  @Override
  public String toString() {
    return elementAdapter + ".collection()";
  }
}