package de.unisiegen.tpml.core ;


/**
 * Abstract base class for classes implementing the <code>ProofRule</code>
 * interface.
 * 
 * @author Benedikt Meurer
 * @version $Rev$
 * @see de.unisiegen.tpml.core.ProofRule
 */
public abstract class AbstractProofRule implements ProofRule
{
  //
  // Attributes
  //
  /**
   * The group id of the proof rule, used to sort the proof rules by group when
   * displaying them to the user.
   * 
   * @see #getGroup()
   */
  private int group ;


  /**
   * The name of the proof rule.
   * 
   * @see #getName()
   */
  private String name ;


  //
  // Constructor (protected)
  //
  /**
   * Allocates a new <code>AbstractProofRule</code> with the specified
   * <code>name</code>.
   * 
   * @param pGroup the group id of the proof rule, see the description of the
   *          {@link #getGroup()} method.
   * @param pName the name of the proof rule.
   * @throws NullPointerException if <code>name</code> is <code>null</code>.
   */
  protected AbstractProofRule ( int pGroup , String pName )
  {
    if ( pName == null )
    {
      throw new NullPointerException ( "name is null" ) ; //$NON-NLS-1$
    }
    this.group = pGroup ;
    this.name = pName ;
  }


  //
  // Accessors
  //
  /**
   * {@inheritDoc}
   * 
   * @see de.unisiegen.tpml.core.ProofRule#getGroup()
   */
  public int getGroup ( )
  {
    return this.group ;
  }


  /**
   * {@inheritDoc}
   * 
   * @see de.unisiegen.tpml.core.ProofRule#getName()
   */
  public String getName ( )
  {
    return this.name ;
  }


  //
  // Comparisons
  //
  /**
   * {@inheritDoc}
   * 
   * @see java.lang.Comparable#compareTo(Object)
   */
  public int compareTo ( ProofRule other )
  {
    // compare groups first
    if ( getGroup ( ) < other.getGroup ( ) )
    {
      return - 1 ;
    }
    else if ( getGroup ( ) > other.getGroup ( ) )
    {
      return 1 ;
    }
    else
    {
      // compare by name
      return getName ( ).compareTo ( other.getName ( ) ) ;
    }
  }


  //
  // Base methods
  //
  /**
   * {@inheritDoc}
   * 
   * @see #getName()
   * @see java.lang.Object#toString()
   */
  @ Override
  public String toString ( )
  {
    return this.name ;
  }


  /**
   * {@inheritDoc} Two proof rules are considered equal if both the name and the
   * class of the proof rule are equal.
   * 
   * @see java.lang.Object#equals(java.lang.Object)
   */
  @ Override
  public boolean equals ( Object obj )
  {
    if ( obj instanceof AbstractProofRule )
    {
      AbstractProofRule other = ( AbstractProofRule ) obj ;
      return ( this.name.equals ( other.name ) && this.getClass ( ).equals (
          other.getClass ( ) ) ) ;
    }
    return false ;
  }


  /**
   * {@inheritDoc}
   * 
   * @see java.lang.Object#hashCode()
   */
  @ Override
  public int hashCode ( )
  {
    return this.name.hashCode ( ) + this.getClass ( ).hashCode ( ) ;
  }
}