production_part.java

package java_cup;


/**
 * This class represents one part (either a symbol or an action) of a
 * production. In this base class it contains only an optional label string that
 * the user can use to refer to the part within actions.
 * <p>
 * This is an abstract class.
 * 
 * @see java_cup.production
 * @version last updated: 11/25/95
 * @author Scott Hudson
 */
@SuppressWarnings (
{ "all" } )
public abstract class production_part
{

  /*-----------------------------------------------------------*/
  /*--- Constructor(s) ----------------------------------------*/
  /*-----------------------------------------------------------*/
  /** Simple constructor. */
  public production_part ( String lab )
  {
    _label = lab;
  }


  /*-----------------------------------------------------------*/
  /*--- (Access to) Instance Variables ------------------------*/
  /*-----------------------------------------------------------*/
  /**
   * Optional label for referring to the part within an action (null for no
   * label).
   */
  protected String _label;


  /**
   * Optional label for referring to the part within an action (null for no
   * label).
   */
  public String label ()
  {
    return _label;
  }


  /*-----------------------------------------------------------*/
  /*--- General Methods ---------------------------------------*/
  /*-----------------------------------------------------------*/
  /**
   * Indicate if this is an action (rather than a symbol). Here in the base
   * class, we don't this know yet, so its an abstract method.
   */
  public abstract boolean is_action ();


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Equality comparison. */
  public boolean equals ( production_part other )
  {
    if ( other == null )
      return false;
    /* compare the labels */
    if ( label () != null )
      return label ().equals ( other.label () );
    else
      return other.label () == null;
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Generic equality comparison. */
  public boolean equals ( Object other )
  {
    if ( ! ( other instanceof production_part ) )
      return false;
    else
      return equals ( ( production_part ) other );
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Produce a hash code. */
  public int hashCode ()
  {
    return label () == null ? 0 : label ().hashCode ();
  }


  /* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . */
  /** Convert to a string. */
  public String toString ()
  {
    if ( label () != null )
      return label () + ":";
    else
      return " ";
  }
  /*-----------------------------------------------------------*/
}