content: /*
   * Created on Oct 26, 2010
   *
   * 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.
   *
   * Copyright @2010-2012 the original author or authors.
   */
  package org.fest.assertions.data;
  
  import static org.fest.util.Objects.HASH_CODE_PRIME;
  
  /**
   * A positive index.
   *
   * @author Alex Ruiz
   */
  public class Index {
    public final int value;
  
    //TODO:(Yvonne) why we need this method.
    /**
     * Creates a new {@link Index}.
     *
     * @param value the value of the index.
     * @return the created {@code Index}.
     * @throws IllegalArgumentException if the given value is negative.
     */
    public static Index atIndex(int value) {
      /*if (value < 0) {
        throw new IllegalArgumentException("The value of the index should not be negative");
      }*/
      return new Index(value);
    }
  
    private Index(int value) {
      if(value < 0) {
        throw new IllegalArgumentException("The value of the index should not be negative");
      }
      this.value = value;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
      if (obj == null) {
        return false;
      }
      if (getClass() != obj.getClass()) {
        return false;
      }
      return value == ((Index) obj).value;
    }
  
    @Override
    public int hashCode() {
      int result = 1;
      result = HASH_CODE_PRIME * result + value;
      return result;
    }
  
    @Override
    public String toString() {
      return String.format("%s[value=%d]", getClass().getSimpleName(), value);
    }
  }
  