01: /*
02: * ============================================================================
03: * GNU Lesser General Public License
04: * ============================================================================
05: *
06: * JasperReports - Free Java report-generating library.
07: * Copyright (C) 2001-2006 JasperSoft Corporation http://www.jaspersoft.com
08: *
09: * 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 10:27:35Z teodord $
35: * @see net.sf.jasperreports.engine.fill.JRExtendedIncrementer
36: */
37: public interface JRCalculable {
38: /**
39: * Constant for the count helper variable.
40: */
41: static final byte HELPER_COUNT = 0;
42:
43: /**
44: * Constant for the sum helper variable.
45: */
46: static final byte HELPER_SUM = 1;
47:
48: /**
49: * Constant for the variance helper variable.
50: */
51: static final byte HELPER_VARIANCE = 2;
52:
53: /**
54: * The number of defined helper variables.
55: */
56: static final int HELPER_SIZE = 3;
57:
58: /**
59: * Returns <code>true</code> iff the calculable object was only initialized and not incremented.
60: *
61: * @return <code>true</code> iff the calculable object was only initialized and not incremented
62: */
63: boolean isInitialized();
64:
65: /**
66: * Sets the initialized flag for this calculable object.
67: * @param isInitialized the initialized flag
68: * @see #isInitialized()
69: */
70: void setInitialized(boolean isInitialized);
71:
72: /**
73: * Returns the incremented value of the calculable object.
74: *
75: * @return the incremented value
76: */
77: Object getIncrementedValue();
78:
79: /**
80: * Returns the value of the calculable object.
81: *
82: * @return the value
83: */
84: Object getValue();
85:
86: /**
87: * Returns a helper variable.
88: *
89: * @param helperType the desired helper variable type
90: * @return the helper variable
91: */
92: JRCalculable getHelperVariable(byte helperType);
93: }
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