01: /**
02: * ========================================
03: * JFreeReport : a free Java report library
04: * ========================================
05: *
06: * Project Info: http://reporting.pentaho.org/
07: *
08: * (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
09: *
10: * This library is free software; you can redistribute it and/or modify it under the terms
11: * of the GNU Lesser General Public License as published by the Free Software Foundation;
12: * either 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, but WITHOUT ANY WARRANTY;
15: * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
16: * See the GNU Lesser General Public License for more details.
17: *
18: * You should have received a copy of the GNU Lesser General Public License along with this
19: * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20: * Boston, MA 02111-1307, USA.
21: *
22: * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
23: * in the United States and other countries.]
24: *
25: * ------------
26: * $Id: PrecomputedValueRegistry.java 3048 2007-07-28 18:02:42Z tmorgner $
27: * ------------
28: * (C) Copyright 2000-2005, by Object Refinery Limited.
29: * (C) Copyright 2005-2007, by Pentaho Corporation.
30: */package org.jfree.report.data;
31:
32: /**
33: * Expression precomputation processes the report in a parallel process to
34: * retrieve the final value of an function. The final value of an expression
35: * is the value the expression would return before it goes out of scope.
36: *
37: * Precomputation can be generally considered expensive, so it should be done
38: * only once. During the precomputation run, no output is generated at all.
39: * Only named data-row expressions can be precomputed.
40: *
41: * @author Thomas Morgner
42: */
43: public interface PrecomputedValueRegistry {
44: public void startElement(PrecomputeNodeKey element);
45:
46: public void finishElement(PrecomputeNodeKey element);
47:
48: public PrecomputeNode currentNode();
49:
50: public void addFunction(final String name, final Object value);
51:
52: public void startElementPrecomputation(
53: final PrecomputeNodeKey element);
54:
55: public void finishElementPrecomputation(
56: final PrecomputeNodeKey element);
57: }
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