/*
 * 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.texera.amber.engine.common

import scala.collection.mutable

class CheckpointState {

  private val states = new mutable.HashMap[String, SerializedState]()

  def save[T <: Any](key: String, state: T): Unit = {
    states(key) = SerializedState.fromObject(state.asInstanceOf[AnyRef], AmberRuntime.serde)
  }

  def has(key: String): Boolean = {
    states.contains(key)
  }

  def load[T <: Any](key: String): T = {
    if (states.contains(key)) {
      states(key).toObject(AmberRuntime.serde).asInstanceOf[T]
    } else {
      throw new RuntimeException(s"no state saved for key = $key")
    }
  }

  def size(): Long = {
    states.filter(_._2 != null).map(_._2.size()).sum
  }

}
