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1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package chapters.onJoran.calculator;
15  
16  import org.xml.sax.Attributes;
17  
18  import ch.qos.logback.core.joran.action.Action;
19  import ch.qos.logback.core.joran.spi.InterpretationContext;
20  import ch.qos.logback.core.util.OptionHelper;
21  
22  /**
23   * This action converts the value attribute of the associated element to an
24   * integer and pushes the resulting Integer object on top of the execution
25   * context stack.
26   * 
27   * <p>It also illustrates usage of Joran's error reporting/handling paradigm.
28   * 
29   * @author Ceki G&uuml;lc&uuml;
30   */
31  public class LiteralAction extends Action {
32      public static final String VALUE_ATR = "value";
33  
34      public void begin(InterpretationContext ic, String name, Attributes attributes) {
35          String valueStr = attributes.getValue(VALUE_ATR);
36  
37          if (OptionHelper.isEmpty(valueStr)) {
38              ic.addError("The literal action requires a value attribute");
39              return;
40          }
41  
42          try {
43              Integer i = Integer.valueOf(valueStr);
44              ic.pushObject(i);
45          } catch (NumberFormatException nfe) {
46              ic.addError("The value [" + valueStr + "] could not be converted to an Integer", nfe);
47              throw nfe;
48          }
49      }
50  
51      public void end(InterpretationContext ic, String name) {
52          // Nothing to do here.
53          // In general, the end() method of actions associated with elements
54          // having no children do not need to perform any processing in their
55          // end() method.
56      }
57  }