JRCalculable


1   /*
2    * ============================================================================
3    * GNU Lesser General Public License
4    * ============================================================================
5    *
6    * JasperReports - Free Java report-generating library.
7    * Copyright (C) 2001-2006 JasperSoft Corporation http://www.jaspersoft.com
8    * 
9    * This library is free software; you can redistribute it and/or
10   * modify it under the terms of the GNU Lesser General Public
11   * License as published by the Free Software Foundation; either
12   * version 2.1 of the License, or (at your option) any later version.
13   * 
14   * This library is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17   * Lesser General Public License for more details.
18   * 
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA.
22   * 
23   * JasperSoft Corporation
24   * 303 Second Street, Suite 450 North
25   * San Francisco, CA 94107
26   * http://www.jaspersoft.com
27   */
28  package net.sf.jasperreports.engine.fill;
29  
30  /**
31   * Interface for objects that can be used by extended incrementers for calculations.
32   * 
33   * @author Lucian Chirita (lucianc@users.sourceforge.net)
34   * @version $Id: JRCalculable.java 1229 2006-04-19 13:27:35 +0300 (Wed, 19 Apr 2006) teodord $
35   * @see net.sf.jasperreports.engine.fill.JRExtendedIncrementer
36   */
37  public interface JRCalculable
38  {
39      /**
40       * Constant for the count helper variable.
41       */
42      static final byte HELPER_COUNT = 0;
43      
44      /**
45       * Constant for the sum helper variable.
46       */
47      static final byte HELPER_SUM = 1;
48      
49      /**
50       * Constant for the variance helper variable.
51       */
52      static final byte HELPER_VARIANCE = 2;
53      
54      /**
55       * The number of defined helper variables.
56       */
57      static final int HELPER_SIZE = 3;
58  
59      
60      /**
61       * Returns <code>true</code> iff the calculable object was only initialized and not incremented.
62       * 
63       * @return <code>true</code> iff the calculable object was only initialized and not incremented
64       */
65      boolean isInitialized();
66      
67      
68      /**
69       * Sets the initialized flag for this calculable object.
70       * @param isInitialized the initialized flag
71       * @see #isInitialized()
72       */
73      void setInitialized(boolean isInitialized);
74  
75      
76      /**
77       * Returns the incremented value of the calculable object.
78       * 
79       * @return the incremented value
80       */
81      Object   getIncrementedValue();
82  
83      
84      /**
85       * Returns the value of the calculable object.
86       * 
87       * @return the value
88       */
89      Object   getValue();
90  
91      
92      /**
93       * Returns a helper variable.
94       * 
95       * @param helperType the desired helper variable type
96       * @return the helper variable
97       */
98      JRCalculable getHelperVariable(byte helperType);
99  }
100
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