001 /** 002 * ======================================== 003 * JFreeReport : a free Java report library 004 * ======================================== 005 * 006 * Project Info: http://reporting.pentaho.org/ 007 * 008 * (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors. 009 * 010 * This library is free software; you can redistribute it and/or modify it under the terms 011 * of the GNU Lesser General Public License as published by the Free Software Foundation; 012 * either version 2.1 of the License, or (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 015 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 016 * See the GNU Lesser General Public License for more details. 017 * 018 * You should have received a copy of the GNU Lesser General Public License along with this 019 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, 020 * Boston, MA 02111-1307, USA. 021 * 022 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 023 * in the United States and other countries.] 024 * 025 * ------------ 026 * $Id: PrecomputedValueRegistry.java 2725 2007-04-01 18:49:29Z taqua $ 027 * ------------ 028 * (C) Copyright 2000-2005, by Object Refinery Limited. 029 * (C) Copyright 2005-2007, by Pentaho Corporation. 030 */ 031 032 package org.jfree.report.data; 033 034 /** 035 * Expression precomputation processes the report in a parallel process to 036 * retrieve the final value of an function. The final value of an expression 037 * is the value the expression would return before it goes out of scope. 038 * 039 * Precomputation can be generally considered expensive, so it should be done 040 * only once. During the precomputation run, no output is generated at all. 041 * Only named data-row expressions can be precomputed. 042 * 043 * @author Thomas Morgner 044 */ 045 public interface PrecomputedValueRegistry 046 { 047 public void startElement (PrecomputeNodeKey element); 048 public void finishElement (PrecomputeNodeKey element); 049 public PrecomputeNode currentNode (); 050 051 public void addFunction(final String name, final Object value); 052 053 public void startElementPrecomputation(final PrecomputeNodeKey element); 054 055 public void finishElementPrecomputation(final PrecomputeNodeKey element); 056 }