Minor improvements to error handling in ForkedEvaluator. Added junits.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@820479 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/ss/formula/eval/forked/ForkedEvaluationSheet.java

@@ -27,6 +27,7 @@ import org.apache.poi.ss.formula.EvaluationWorkbook;
 import org.apache.poi.ss.usermodel.Cell;
 import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.util.CellReference;
 
 /**
  * Represents a sheet being used for forked evaluation.  Initially, objects of this class contain
@@ -65,6 +66,11 @@ final class ForkedEvaluationSheet implements EvaluationSheet {
 		ForkedEvaluationCell result = _sharedCellsByRowCol.get(key);
 		if (result == null) {
 			EvaluationCell mcell = _masterSheet.getCell(rowIndex, columnIndex);
+			if (mcell == null) {
+				CellReference cr = new CellReference(rowIndex, columnIndex);
+				throw new UnsupportedOperationException("Underlying cell '"
+						+ cr.formatAsString() + "' is missing in master sheet.");
+			}
 			result = new ForkedEvaluationCell(this, mcell);
 			_sharedCellsByRowCol.put(key, result);
 		}

src/testcases/org/apache/poi/ss/formula/AllSSFormulaTests.java

@@ -17,6 +17,8 @@
 
 package org.apache.poi.ss.formula;
 
+import org.apache.poi.ss.formula.eval.forked.TestForkedEvaluator;
+
 import junit.framework.Test;
 import junit.framework.TestSuite;
 /**
@@ -30,6 +32,7 @@ public final class AllSSFormulaTests {
 		result.addTestSuite(TestCellCacheEntry.class);
 		result.addTestSuite(TestEvaluationCache.class);
 		result.addTestSuite(TestWorkbookEvaluator.class);
+		result.addTestSuite(TestForkedEvaluator.class);
 		return result;
 	}
 }

src/testcases/org/apache/poi/ss/formula/eval/forked/TestForkedEvaluator.java

@@ -0,0 +1,118 @@
+/* ====================================================================
+   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.formula.eval.forked;
+
+import junit.framework.AssertionFailedError;
+import junit.framework.TestCase;
+
+import org.apache.poi.hssf.record.formula.eval.NumberEval;
+import org.apache.poi.hssf.usermodel.HSSFRow;
+import org.apache.poi.hssf.usermodel.HSSFSheet;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.formula.IStabilityClassifier;
+
+/**
+ * @author Josh Micich
+ */
+public final class TestForkedEvaluator extends TestCase {
+	/**
+	 * set up a calculation workbook with input cells nicely segregated on a
+	 * sheet called "Inputs"
+	 */
+	private static HSSFWorkbook createWorkbook() {
+		HSSFWorkbook wb = new HSSFWorkbook();
+		HSSFSheet sheet1 = wb.createSheet("Inputs");
+		HSSFSheet sheet2 = wb.createSheet("Calculations");
+		HSSFRow row;
+		row = sheet2.createRow(0);
+		row.createCell(0).setCellFormula("B1*Inputs!A1-Inputs!B1");
+		row.createCell(1).setCellValue(5.0); // Calculations!B1
+
+		// some default input values
+		row = sheet1.createRow(0);
+		row.createCell(0).setCellValue(2.0); // Inputs!A1
+		row.createCell(1).setCellValue(3.0); // Inputs!B1
+		return wb;
+	}
+
+	/**
+	 * Shows a basic use-case for {@link ForkedEvaluator}
+	 */
+	public void testBasic() {
+		HSSFWorkbook wb = createWorkbook();
+
+		// The stability classifier is useful to reduce memory consumption of caching logic
+		IStabilityClassifier stabilityClassifier = new IStabilityClassifier() {
+			public boolean isCellFinal(int sheetIndex, int rowIndex, int columnIndex) {
+				return sheetIndex == 1;
+			}
+		};
+
+		ForkedEvaluator fe1 = ForkedEvaluator.create(wb, stabilityClassifier, null);
+		ForkedEvaluator fe2 = ForkedEvaluator.create(wb, stabilityClassifier, null);
+
+		// fe1 and fe2 can be used concurrently on separate threads
+
+		fe1.updateCell("Inputs", 0, 0, new NumberEval(4.0));
+		fe1.updateCell("Inputs", 0, 1, new NumberEval(1.1));
+
+		fe2.updateCell("Inputs", 0, 0, new NumberEval(1.2));
+		fe2.updateCell("Inputs", 0, 1, new NumberEval(2.0));
+
+		assertEquals(18.9, ((NumberEval) fe1.evaluate("Calculations", 0, 0)).getNumberValue(), 0.0);
+		assertEquals(4.0, ((NumberEval) fe2.evaluate("Calculations", 0, 0)).getNumberValue(), 0.0);
+		fe1.updateCell("Inputs", 0, 0, new NumberEval(3.0));
+		assertEquals(13.9, ((NumberEval) fe1.evaluate("Calculations", 0, 0)).getNumberValue(), 0.0);
+	}
+
+	/**
+	 * As of Sep 2009, the Forked evaluator can update values from existing cells (this is because
+	 * the underlying 'master' cell is used as a key into the calculation cache.  Prior to the fix
+	 * for this bug, an attempt to update a missing cell would result in NPE.  This junit tests for
+	 * a more meaningful error message.<br/>
+	 *
+	 * An alternate solution might involve allowing empty cells to be created as necessary.  That
+	 * was considered less desirable because so far, the underlying 'master' workbook is strictly
+	 * <i>read-only</i> with respect to the ForkedEvaluator.
+	 */
+	public void testMissingInputCell() {
+		HSSFWorkbook wb = createWorkbook();
+
+		ForkedEvaluator fe = ForkedEvaluator.create(wb, null, null);
+
+		// attempt update input at cell A2 (which is missing)
+		try {
+			fe.updateCell("Inputs", 1, 0, new NumberEval(4.0));
+			throw new AssertionFailedError(
+					"Expected exception to be thrown due to missing input cell");
+		} catch (NullPointerException e) {
+			StackTraceElement[] stes = e.getStackTrace();
+			if (stes[0].getMethodName().equals("getIdentityKey")) {
+				throw new AssertionFailedError("Identified bug with update of missing input cell");
+			}
+			throw e;
+		} catch (UnsupportedOperationException e) {
+			if (e.getMessage().equals(
+					"Underlying cell 'A2' is missing in master sheet.")) {
+				// expected during successful test
+			} else {
+				throw e;
+			}
+		}
+	}
+}