package jalview.util;

/**
 * A class to wrap a case insensitive string. For use in collections where we
 * want to preserve case, but do not want to duplicate upper and lower case
 * variants
 */
public final class CaseInsensitiveString
{
  String value;

  public CaseInsensitiveString(String s)
  {
    this.value = s;
  }

  @Override
  public String toString()
  {
    return value;
  }

  /**
   * Answers true if the object compared to is a CaseInsensitiveString wrapping
   * the same string value (ignoring case), or if both wrap a null value, else
   * false
   */
  @Override
  public boolean equals(Object o)
  {
    if (o == null)
    {
      return false;
    }
    if (!(o instanceof CaseInsensitiveString))
    {
      return false;
    }
    CaseInsensitiveString obj = (CaseInsensitiveString) o;
    if (value == null)
    {
      return obj.value == null;
    }
    return value.equalsIgnoreCase(obj.value);
  }

  /**
   * hashCode overriden to guarantee that 'equal' objects have the same hash
   * code
   */
  @Override
  public int hashCode()
  {
    return value == null ? super.hashCode() : value.toUpperCase()
            .hashCode();
  }
}