RealmListAdapter.kt

package de.wdv.apps.yoursingapore.core.moshi

import com.squareup.moshi.JsonAdapter
import com.squareup.moshi.JsonReader
import com.squareup.moshi.JsonWriter
import com.squareup.moshi.Types
import io.realm.RealmList
import io.realm.RealmModel


/*
 * Copyright 2017 Markus Wedler.
 *
 * 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
 *
 *     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.
 */

class RealmListAdapter<T : RealmModel>(
    val elementAdapter: JsonAdapter<T>) : JsonAdapter<RealmList<T>>() {

  companion object {

    val FACTORY: Factory = Factory { type, annotations, moshi ->
      val rawType: Class<*> = Types.getRawType(type)

      if (rawType == RealmList::class.java) {
        val elementType = Types.collectionElementType(type, RealmList::class.java)
        val elementAdapter = moshi.adapter<RealmModel>(elementType)
        return@Factory RealmListAdapter(elementAdapter).nullSafe()
      }
      null
    }
  }

  override fun fromJson(reader: JsonReader): RealmList<T> {

    val result = RealmList<T>()
    reader.beginArray()
    while (reader.hasNext()) {
      result.add(elementAdapter.fromJson(reader))
    }
    reader.endArray()
    return result
  }

  override fun toJson(writer: JsonWriter, value: RealmList<T>) {
    writer.beginArray()
    for (element in value) {
      elementAdapter.toJson(writer, element)
    }
    writer.endArray()
  }
}