/*
    * 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.giraph.block_app.framework.block;
  
  import com.google.common.base.Objects;
  
  /**
   * Number of pieces
   */
  public class PieceCount {
    private boolean known;
    private int count;
  
    public PieceCount(int count) {
      known = true;
      this.count = count;
    }
  
    private PieceCount() {
      known = false;
    }
  
    public static PieceCount createUnknownCount() {
      return new PieceCount();
    }
  
  
    public PieceCount add(PieceCount other) {
      if (!this.known || !other.known) {
        known = false;
      } else {
        count += other.count;
      }
      return this;
    }
  
    public PieceCount multiply(int value) {
      count *= value;
      return this;
    }
  
    public int getCount() {
      if (known) {
        return count;
      } else {
        throw new IllegalStateException(
            "Can't get superstep count when it's unknown");
      }
    }
  
    public boolean isKnown() {
      return known;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj instanceof PieceCount) {
        PieceCount other = (PieceCount) obj;
        if (known) {
          return other.known && other.count == count;
        } else {
          return !other.known;
        }
      }
      return false;
    }
  
    @Override
    public int hashCode() {
      return Objects.hashCode(known, count);
    }
  }