1 /*
   2  * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.tools.jstat;
  27 
  28 import java.text.*;
  29 import sun.jvmstat.monitor.MonitorException;
  30 
  31 /**
  32  * A class implementing the Closure interface which is used to resolve
  33  * all the symbols in the expressions contained in ColumnFormat objects.
  34  *
  35  * @author Brian Doherty
  36  * @since 1.5
  37  */
  38 public class SymbolResolutionClosure implements Closure {
  39     private static final boolean debug =
  40             Boolean.getBoolean("SymbolResolutionClosure.debug");
  41 
  42     private ExpressionEvaluator ee;
  43 
  44     public SymbolResolutionClosure(ExpressionEvaluator ee) {
  45         this.ee = ee;
  46     }
  47 
  48     public void visit(Object o, boolean hasNext) throws MonitorException {
  49         if (! (o instanceof ColumnFormat)) {
  50             return;
  51         }
  52 
  53         ColumnFormat c = (ColumnFormat)o;
  54         Expression e = c.getExpression();
  55         String previous = e.toString();
  56         e = (Expression)ee.evaluate(e);
  57         if (debug) {
  58             System.out.print("Expression: " + previous + " resolved to "
  59                              + e.toString());
  60         }
  61         c.setExpression(e);
  62     }
  63 }