/*
    *
    * The DbUnit Database Testing Framework
    * Copyright (C)2005, DbUnit.org
    *
    * This library is free software; you can redistribute it and/or
    * modify it under the terms of the GNU Lesser General Public
    * License as published by the Free Software Foundation; either
    * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  package org.dbunit.util.search;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Basic implementation of the {@link IEdge} interface.
   * 
   * @author Felipe Leme (dbunit@felipeal.net)
   * @author Last changed by: $Author$
   * @version $Revision$ $Date$
   * @since 2.2.0 (Aug 25, 2005)
   */
  public class Edge implements IEdge {
  
      /**
       * Logger for this class
       */
      private static final Logger logger = LoggerFactory.getLogger(Edge.class);
  
      private final Comparable<String> nodeFrom;
      private final Comparable<String> nodeTo;
  
      /**
       * @param nodeFrom
       * @param nodeTo
       */
      public Edge(final Comparable<String> nodeFrom, final Comparable<String> nodeTo) {
          if (nodeFrom == null) {
              throw new IllegalArgumentException("node from cannot be null");
          }
          if (nodeTo == null) {
              throw new IllegalArgumentException("node to cannot be null");
          }
          this.nodeFrom = nodeFrom;
          this.nodeTo = nodeTo;
      }
  
      @Override
      public Object getFrom() {
          return this.nodeFrom;
      }
  
      @Override
      public Object getTo() {
          return this.nodeTo;
      }
  
      @Override
      public String toString() {
          return this.nodeFrom + "->" + this.nodeTo;
      }
  
      /**
       * Compares this edge to the given one using 
       * the <code>{@link #getFrom()}</code> nodes first. 
       * If those are equal the <code>{@link #getTo()}}</code>
       * is used for comparison.
       * @see java.lang.Comparable#compareTo(java.lang.Object)
       */
      @Override
      public int compareTo(final Object o) {
          logger.debug("compareTo(o={}) - start", o);
  
          final Edge otherEdge = (Edge) o;
          int result = this.nodeFrom.compareTo((String) otherEdge.getFrom());
          if ( result == 0 ) {
              result = this.nodeTo.compareTo((String) otherEdge.getTo());
          }
          return result;
      }
  
      @Override
      public int hashCode() {
          final int prime = 31;
          int result = 1;
          result = prime * result
                  + ((nodeFrom == null) ? 0 : nodeFrom.hashCode());
          result = prime * result + ((nodeTo == null) ? 0 : nodeTo.hashCode());
         return result;
     }
 
     @Override
     public boolean equals(final Object obj) {
         if (this == obj)
             return true;
         if (obj == null)
             return false;
         if (getClass() != obj.getClass())
             return false;
         final Edge other = (Edge) obj;
         if (nodeFrom == null) {
             if (other.nodeFrom != null)
                 return false;
         } else if (!nodeFrom.equals(other.nodeFrom))
             return false;
         if (nodeTo == null) {
             if (other.nodeTo != null)
                 return false;
         } else if (!nodeTo.equals(other.nodeTo))
             return false;
         return true;
     }
 
 }