content: /* Alloy Analyzer 4 -- Copyright (c) 2006-2009, Felix Chang
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files
   * (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify,
   * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
   * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
   * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  package edu.mit.csail.sdg.alloy4;
  
  /**
   * Immutable; this is the abstract parent class of the various possible errors.
   */
  
  public abstract class Err extends RuntimeException {
  
      /** This ensures this class can be serialized reliably. */
      private static final long serialVersionUID = 0;
  
      /**
       * This stores the filename/line/column information (Pos.UNKNOWN if unknown)
       * (never null)
       */
      public final Pos          pos;
  
      /** The actual error message (never null) */
      public final String       msg;
  
      /**
       * Constructs a new Err object.
       *
       * @param pos - the filename/line/row information (can be null if unknown)
       * @param msg - the actual error message (can be null)
       * @param cause - if nonnull, it will be recorded as the cause of this exception
       */
      Err(Pos pos, String msg, Throwable cause) {
          super((msg == null ? "" : msg), cause);
          this.pos = (pos == null ? Pos.UNKNOWN : pos);
          this.msg = (msg == null ? "" : msg);
      }
  
      /**
       * Two Err objects are equal if the type, position, and message are the same.
       */
      @Override
      public final boolean equals(Object other) {
          if (this == other)
              return true;
          else if (other == null || getClass() != other.getClass())
              return false;
          Err that = (Err) other;
          return pos.equals(that.pos) && msg.equals(that.msg);
      }
  
      /** Returns a hash code consistent with equals() */
      @Override
      public final int hashCode() {
          return msg.hashCode();
      }
  
      /**
       * Returns this exception type, its error message, and its complete stack trace
       * as a String.
       */
      public final String dump() {
          return MailBug.dump(this);
      }
  }
  