/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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namespace HH.WMS.Utils.NPOI.SS.Formula
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{
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/**
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* Used to help optimise cell evaluation result caching by allowing applications to specify which
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* parts of a workbook are <em>final</em>.<br/>
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* The term <b>final</b> is introduced here to denote immutability or 'having constant definition'.
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* This classification refers to potential actions (on the evaluated workbook) by the evaluating
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* application. It does not refer to operations performed by the evaluator ({@link
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* WorkbookEvaluator}).<br/>
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* <br/>
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* <b>General guidelines</b>:
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* <ul>
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* <li>a plain value cell can be marked as 'final' if it will not be changed after the first call
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* to {@link WorkbookEvaluator#evaluate(EvaluationCell)}.
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* </li>
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* <li>a formula cell can be marked as 'final' if its formula will not be changed after the first
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* call to {@link WorkbookEvaluator#evaluate(EvaluationCell)}. This remains true even if changes
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* in dependent values may cause the evaluated value to change.</li>
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* <li>plain value cells should be marked as 'not final' if their plain value value may change.
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* </li>
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* <li>formula cells should be marked as 'not final' if their formula definition may change.</li>
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* <li>cells which may switch between plain value and formula should also be marked as 'not final'.
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* </li>
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* </ul>
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* <b>Notes</b>:
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* <ul>
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* <li>If none of the spreadsheet cells is expected to have its definition changed after evaluation
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* begins, every cell can be marked as 'final'. This is the most efficient / least resource
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* intensive option.</li>
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* <li>To retain freedom to change any cell definition at any time, an application may classify all
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* cells as 'not final'. This freedom comes at the expense of greater memory consumption.</li>
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* <li>For the purpose of these classifications, setting the cached formula result of a cell (for
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* example in {@link HSSFFormulaEvaluator#evaluateFormulaCell(org.apache.poi.ss.usermodel.Cell)})
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* does not constitute changing the definition of the cell.</li>
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* <li>Updating cells which have been classified as 'final' will cause the evaluator to behave
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* unpredictably (typically ignoring the update).</li>
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* </ul>
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*
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* @author Josh Micich
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*/
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public abstract class IStabilityClassifier
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{
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/**
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* Convenience implementation for situations where all cell definitions remain fixed after
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* evaluation begins.
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*/
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static IStabilityClassifier TOTALLY_IMMUTABLE = new TotallyImmutable();
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/**
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* Checks if a cell's value(/formula) is fixed - in other words - not expected to be modified
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* between calls to the evaluator. (Note - this is an independent concept from whether a
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* formula cell's evaluated value may change during successive calls to the evaluator).
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*
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* @param sheetIndex zero based index into workbook sheet list
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* @param rowIndex zero based row index of cell
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* @param columnIndex zero based column index of cell
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* @return <c>false</c> if the evaluating application may need to modify the specified
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* cell between calls to the evaluator.
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*/
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public abstract bool IsCellFinal(int sheetIndex, int rowIndex, int columnIndex);
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}
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public class TotallyImmutable : IStabilityClassifier
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{
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public override bool IsCellFinal(int sheetIndex, int rowIndex, int columnIndex)
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{
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return true;
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}
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};
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}
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