logicalnotexpression.java

来自「linux下建立JAVA虚拟机的源码KAFFE」· Java 代码 · 共 44 行

/* gnu.classpath.tools.gjdoc.expr.LogicalNotExpression
   Copyright (C) 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
 
GNU Classpath 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
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */

package gnu.classpath.tools.gjdoc.expr;

class LogicalNotExpression
   extends UnaryExpression
{
   protected LogicalNotExpression(Expression expr)
   {
      super(expr);
   }

   public ConstantExpression evaluate(Context context)
      throws IllegalExpressionException
   {
      ConstantExpression value = expr.evaluate(context);

      if (Type.BOOLEAN == value.getType()) {
         return new ConstantBoolean(!((ConstantBoolean)value).booleanValue());
      }
      else {
         throw new IllegalExpressionException("Operator ! cannot be applied to " + value.getType());
      }
   }
}