Kawa/gnu/mapping/ReadOnlyLocation.java

// Copyright (c) 2005  Per M.A. Bothner.
// This is free software;  for terms and warranty disclaimer see ./COPYING.

package gnu.mapping;

public class ReadOnlyLocation extends ConstrainedLocation
{
  public static ReadOnlyLocation make (Location base)
  {
    ReadOnlyLocation rloc = new ReadOnlyLocation();
    rloc.base = base;
    return rloc;
  }

  public boolean isConstant ()
  {
    return true;
  }

  protected Object coerce (Object newValue)
  {
    StringBuffer sbuf
      = new StringBuffer("attempt to modify read-only location");
    Symbol name = getKeySymbol();
    if (name != null)
      {
	sbuf.append(": ");
	sbuf.append(name);
      }
    throw new IllegalStateException(sbuf.toString());
  }

}