From 16ea202e52424ca318b7008ed3d850548e5d3854 Mon Sep 17 00:00:00 2001
From: Yegor Kozlov <yegor@apache.org>
Date: Tue, 7 Feb 2012 08:11:37 +0000
Subject: [PATCH] added HSSFFormulaEvaluator.setIgnoreMissingWorkbooks, see
 Bugzilla 52575

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1241372 13f79535-47bb-0310-9956-ffa450edef68
---
 .../hssf/usermodel/HSSFFormulaEvaluator.java  | 20 ++++++++++++
 .../poi/ss/formula/WorkbookEvaluator.java     | 32 +++++++++++++------
 .../poi/ss/formula/TestMissingWorkbook.java   |  6 ++--
 3 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java b/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
index 86c85f02b3..5d01e7a63a 100644
--- a/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
+++ b/src/java/org/apache/poi/hssf/usermodel/HSSFFormulaEvaluator.java
@@ -369,4 +369,24 @@ public class HSSFFormulaEvaluator implements FormulaEvaluator  {
 		}
 		throw new RuntimeException("Unexpected eval class (" + eval.getClass().getName() + ")");
 	}
+
+    /**
+     * Whether to ignore missing references to external workbooks and
+     * use cached formula results in the main workbook instead.
+     * <p>
+     * In some cases exetrnal workbooks referenced by formulas in the main workbook are not avaiable.
+     * With this method you can control how POI handles such missing references:
+     * <ul>
+     *     <li>by default ignoreMissingWorkbooks=false and POI throws {@link org.apache.poi.ss.formula.CollaboratingWorkbooksEnvironment.WorkbookNotFoundException}
+     *     if an external reference cannot be resolved</li>
+     *     <li>if ignoreMissingWorkbooks=true then POI uses cached formula result
+     *     that already exists in the main workbook</li>
+     * </ul>
+     *
+     * @param ignore whether to ignore missing references to external workbooks
+     */
+    public void setIgnoreMissingWorkbooks(boolean ignore){
+        _bookEvaluator.setIgnoreMissingWorkbooks(ignore);
+    }
+
 }
diff --git a/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java b/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
index 3807c9c291..e6d4da22f9 100644
--- a/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
+++ b/src/java/org/apache/poi/ss/formula/WorkbookEvaluator.java
@@ -85,12 +85,6 @@ public final class WorkbookEvaluator {
 	
 	private static final POILogger LOG = POILogFactory.getLogger(WorkbookEvaluator.class);
 
-    /**
-     * Whether to use cached formula results if external workbook references in a formula is not available.
-     * See Bugzilla 52575 for details.
-     */
-    private static final String IGNORE_MISSING_WORKBOOKS = WorkbookEvaluator.class.getName() + ".IGNORE_MISSING_WORKBOOKS";
-
     private final EvaluationWorkbook _workbook;
 	private EvaluationCache _cache;
 	/** part of cache entry key (useful when evaluating multiple workbooks) */
@@ -103,6 +97,8 @@ public final class WorkbookEvaluator {
 	private final IStabilityClassifier _stabilityClassifier;
 	private final AggregatingUDFFinder _udfFinder;
 
+    private boolean _ignoreMissingWorkbooks = false;
+
 	/**
 	 * @param udfFinder pass <code>null</code> for default (AnalysisToolPak only)
 	 */
@@ -310,9 +306,7 @@ public final class WorkbookEvaluator {
 			 catch (NotImplementedException e) {
 				throw addExceptionInfo(e, sheetIndex, rowIndex, columnIndex);
 			 } catch (RuntimeException re) {
-				 if (re.getCause() instanceof WorkbookNotFoundException 
-						 //To be replaced by configuration infrastructure
-						 && Boolean.valueOf(System.getProperty(IGNORE_MISSING_WORKBOOKS))) {
+				 if (re.getCause() instanceof WorkbookNotFoundException && _ignoreMissingWorkbooks) {
  					logInfo(re.getCause().getMessage() + " - Continuing with cached value!");
  					switch(srcCell.getCachedFormulaResultType()) {
 	 					case Cell.CELL_TYPE_NUMERIC:
@@ -671,4 +665,24 @@ public final class WorkbookEvaluator {
 	public FreeRefFunction findUserDefinedFunction(String functionName) {
 		return _udfFinder.findFunction(functionName);
 	}
+
+    /**
+     * Whether to ignore missing references to external workbooks and
+     * use cached formula results in the main workbook instead.
+     * <p>
+     * In some cases exetrnal workbooks referenced by formulas in the main workbook are not avaiable.
+     * With this method you can control how POI handles such missing references:
+     * <ul>
+     *     <li>by default ignoreMissingWorkbooks=false and POI throws {@link WorkbookNotFoundException}
+     *     if an external reference cannot be resolved</li>
+     *     <li>if ignoreMissingWorkbooks=true then POI uses cached formula result
+     *     that already exists in the main workbook</li>
+     * </ul>
+     *
+     * @param ignore whether to ignore missing references to external workbooks
+     * @see <a href="https://issues.apache.org/bugzilla/show_bug.cgi?id=52575">Bug 52575</a> for details
+     */
+    public void setIgnoreMissingWorkbooks(boolean ignore){
+        _ignoreMissingWorkbooks = ignore;
+    }
 }
diff --git a/src/testcases/org/apache/poi/ss/formula/TestMissingWorkbook.java b/src/testcases/org/apache/poi/ss/formula/TestMissingWorkbook.java
index 7b639f996e..faf943dbfe 100644
--- a/src/testcases/org/apache/poi/ss/formula/TestMissingWorkbook.java
+++ b/src/testcases/org/apache/poi/ss/formula/TestMissingWorkbook.java
@@ -72,9 +72,9 @@ public class TestMissingWorkbook extends TestCase {
 		assertEquals(Cell.CELL_TYPE_FORMULA, lB1Cell.getCellType());
 		assertEquals(Cell.CELL_TYPE_FORMULA, lC1Cell.getCellType());
 		
-		FormulaEvaluator evaluator = mainWorkbook.getCreationHelper().createFormulaEvaluator();
-		
-		System.setProperty(propertyKey, Boolean.toString(true));
+		HSSFFormulaEvaluator evaluator = mainWorkbook.getCreationHelper().createFormulaEvaluator();
+        evaluator.setIgnoreMissingWorkbooks(true);
+
 		assertEquals(Cell.CELL_TYPE_NUMERIC, evaluator.evaluateFormulaCell(lA1Cell));
 		assertEquals(Cell.CELL_TYPE_STRING, evaluator.evaluateFormulaCell(lB1Cell));
 		assertEquals(Cell.CELL_TYPE_BOOLEAN, evaluator.evaluateFormulaCell(lC1Cell));