Formula evaluation and error handling example - reports what cells can't be evaluated...

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1607583 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/src/examples/src/org/apache/poi/ss/examples/formula/CheckFunctionsSupported.java b/src/examples/src/org/apache/poi/ss/examples/formula/CheckFunctionsSupported.java
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+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+package org.apache.poi.ss.examples.formula;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
+
+import org.apache.poi.ss.formula.eval.NotImplementedException;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.FormulaEvaluator;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.ss.usermodel.WorkbookFactory;
+import org.apache.poi.ss.util.CellReference;
+
+/**
+ * Attempts to re-evaluate all the formulas in the workbook, and
+ *  reports what (if any) formula functions used are not (currently)
+ *  supported by Apache POI.
+ *
+ * <p>This provides examples of how to evaluate formulas in excel
+ *  files using Apache POI, along with how to handle errors whilst
+ *  doing so.
+ */
+public class CheckFunctionsSupported {
+    public static void main(String[] args) throws Exception {
+        if (args.length < 1) {
+            System.err.println("Use:");
+            System.err.println("  CheckFunctionsSupported <filename>");
+            return;
+        }
+        
+        Workbook wb = WorkbookFactory.create(new File(args[0]));
+        CheckFunctionsSupported check = new CheckFunctionsSupported(wb);
+        
+        // Fetch all the problems
+        List<FormulaEvaluationProblems> problems = new ArrayList<CheckFunctionsSupported.FormulaEvaluationProblems>();
+        for (int sn=0; sn<wb.getNumberOfSheets(); sn++) {
+            problems.add(check.getEvaluationProblems(sn));
+        }
+        
+        // Produce an overall summary
+        Set<String> unsupportedFunctions = new TreeSet<String>();
+        for (FormulaEvaluationProblems p : problems) {
+            unsupportedFunctions.addAll(p.unsupportedFunctions);
+        }
+        if (unsupportedFunctions.isEmpty()) {
+            System.out.println("There are no unsupported formula functions used");
+        } else {
+            System.out.println("Unsupported formula functions:");
+            for (String function : unsupportedFunctions) {
+                System.out.println("  " + function);
+            }
+            System.out.println("Total unsupported functions = " + unsupportedFunctions.size());
+        }
+        
+        // Report sheet by sheet
+        for (int sn=0; sn<wb.getNumberOfSheets(); sn++) {
+            String sheetName = wb.getSheetName(sn);
+            FormulaEvaluationProblems probs = problems.get(sn);
+            
+            System.out.println();
+            System.out.println("Sheet = " + sheetName);
+            
+            if (probs.unevaluatableCells.isEmpty()) {
+                System.out.println(" All cells evaluated without error");
+            } else {
+                for (CellReference cr : probs.unevaluatableCells.keySet()) {
+                    System.out.println(" " + cr.formatAsString() + " - " + 
+                                       probs.unevaluatableCells.get(cr).toString());
+                }
+            }
+        }
+    }
+    
+    private Workbook workbook;
+    private FormulaEvaluator evaluator;
+    public CheckFunctionsSupported(Workbook workbook) {
+        this.workbook = workbook;
+        this.evaluator = workbook.getCreationHelper().createFormulaEvaluator();
+    }
+    
+    public Set<String> getUnsupportedFunctions(String sheetName) {
+        return getUnsupportedFunctions(workbook.getSheet(sheetName));
+    }
+    public Set<String> getUnsupportedFunctions(int sheetIndex) {
+        return getUnsupportedFunctions(workbook.getSheetAt(sheetIndex));
+    }
+    public Set<String> getUnsupportedFunctions(Sheet sheet) {
+        FormulaEvaluationProblems problems = getEvaluationProblems(sheet);
+        return problems.unsupportedFunctions;
+    }
+    
+    public FormulaEvaluationProblems getEvaluationProblems(String sheetName) {
+        return getEvaluationProblems(workbook.getSheet(sheetName));
+    }
+    public FormulaEvaluationProblems getEvaluationProblems(int sheetIndex) {
+        return getEvaluationProblems(workbook.getSheetAt(sheetIndex));
+    }
+    public FormulaEvaluationProblems getEvaluationProblems(Sheet sheet) {
+        Set<String> unsupportedFunctions = new HashSet<String>();
+        Map<CellReference,Exception> unevaluatableCells = new HashMap<CellReference, Exception>();
+        
+        for (Row r : sheet) {
+            for (Cell c : r) {
+                try {
+                    evaluator.evaluate(c);
+                } catch (Exception e) {
+                    if (e instanceof NotImplementedException) {
+                        NotImplementedException nie = (NotImplementedException)e;
+                        // TODO
+                        System.err.println("TODO - Not Implemented: " + nie);
+                    }
+                    unevaluatableCells.put(new CellReference(c), e);
+                }
+            }
+        }
+        
+        return new FormulaEvaluationProblems(unsupportedFunctions, unevaluatableCells);
+    }
+    
+    public static class FormulaEvaluationProblems {
+        /** Which used functions are unsupported by POI at this time */
+        public Set<String> unsupportedFunctions;
+        /** Which cells had unevaluatable formulas, and why? */
+        public Map<CellReference,Exception> unevaluatableCells;
+        
+        protected FormulaEvaluationProblems(Set<String> unsupportedFunctions,
+                             Map<CellReference, Exception> unevaluatableCells) {
+            this.unsupportedFunctions = Collections.unmodifiableSet(unsupportedFunctions);
+            this.unevaluatableCells = Collections.unmodifiableMap(unevaluatableCells);
+        }
+    }
+}