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bug 58885: performance regression on XSSFSheet.addMergedRegion(CellRangeAddress). Add an unsafe version of addMergedRegion that doesn't check for overlapping merged regions

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git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1727776 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Javen O'Neal 2016-01-31 03:27:35 +00:00
parent a79dfd18e4
commit e365e9cbac
2 changed files with 146 additions and 12 deletions
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106
src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFSheet.java
View File

@ -295,24 +295,60 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
}
/**
* Adds a merged region of cells (hence those cells form one).
* Adds a merged region of cells on a sheet.
*
* @param region (rowfrom/colfrom-rowto/colto) to merge
* @param region to merge
* @return index of this region
* @throws IllegalStateException if region intersects with a multi-cell array formula
* @throws IllegalStateException if region intersects with an existing region on this sheet
*/
@Override
public int addMergedRegion(CellRangeAddress region) {
region.validate(SpreadsheetVersion.EXCEL2007);
return addMergedRegion(region, true);
}
// throw IllegalStateException if the argument CellRangeAddress intersects with
// a multi-cell array formula defined in this sheet
validateArrayFormulas(region);
/**
* Adds a merged region of cells (hence those cells form one).
* Skips validation. It is possible to create overlapping merged regions
* or create a merged region that intersects a multi-cell array formula
* with this formula, which may result in a corrupt workbook.
*
* To check for merged regions overlapping array formulas or other merged regions
* after addMergedRegionUnsafe has been called, call {@link #validateArrayFormulas()} and {@link #validateMergedRegions()}
*
* @param region to merge
* @return index of this region
*/
public int addMergedRegionUnsafe(CellRangeAddress region) {
return addMergedRegion(region, false);
}
/**
* Adds a merged region of cells (hence those cells form one).
* If validate is true, check to make sure adding the merged region to the sheet doesn't create a corrupt workbook
* If validate is false, skips the expensive merged region checks, but may produce a corrupt workbook.
*
* @param region to merge
* @param validate whether to validate merged region
* @return index of this region
* @throws IllegalStateException if region intersects with a multi-cell array formula
* @throws IllegalStateException if region intersects with an existing region on this sheet
*/
private int addMergedRegion(CellRangeAddress region, boolean validate) {
if (region.getNumberOfCells() < 2) {
throw new IllegalArgumentException("Merged region " + region.formatAsString() + " must contain 2 or more cells");
}
region.validate(SpreadsheetVersion.EXCEL2007);
// Throw IllegalStateException if the argument CellRangeAddress intersects with
// a merged region already in this sheet
validateMergedRegions(region);
if (validate) {
// throw IllegalStateException if the argument CellRangeAddress intersects with
// a multi-cell array formula defined in this sheet
validateArrayFormulas(region);
// Throw IllegalStateException if the argument CellRangeAddress intersects with
// a merged region already in this sheet
validateMergedRegions(region);
}
CTMergeCells ctMergeCells = worksheet.isSetMergeCells() ? worksheet.getMergeCells() : worksheet.addNewMergeCells();
CTMergeCell ctMergeCell = ctMergeCells.addNewMergeCell();
@ -331,6 +367,7 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
int firstColumn = region.getFirstColumn();
int lastRow = region.getLastRow();
int lastColumn = region.getLastColumn();
// for each cell in sheet, if cell belongs to an array formula, check if merged region intersects array formula cells
for (int rowIn = firstRow; rowIn <= lastRow; rowIn++) {
for (int colIn = firstColumn; colIn <= lastColumn; colIn++) {
XSSFRow row = getRow(rowIn);
@ -342,6 +379,7 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
if(cell.isPartOfArrayFormulaGroup()){
CellRangeAddress arrayRange = cell.getArrayFormulaRange();
if (arrayRange.getNumberOfCells() > 1 &&
// region.intersects(arrayRange) is more concise and probably correct. Is it equivalent?
( arrayRange.isInRange(region.getFirstRow(), region.getFirstColumn()) ||
arrayRange.isInRange(region.getFirstRow(), region.getFirstColumn())) ){
String msg = "The range " + region.formatAsString() + " intersects with a multi-cell array formula. " +
@ -351,13 +389,26 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
}
}
}
}
/**
* Verify that none of the merged regions intersect a multi-cell array formula in this sheet
*
* @param region
* @throws IllegalStateException if candidate region intersects an existing array formula in this sheet
*/
private void checkForMergedRegionsIntersectingArrayFormulas() {
for (CellRangeAddress region : getMergedRegions()) {
validateArrayFormulas(region);
}
}
/**
* Verify that candidate region does not intersect with an existing merged region in this sheet
*
* @param candidateRegion
* @throws IllegalStateException if candidate region intersects an existing merged region in this sheet
* @throws IllegalStateException if candidate region intersects an existing merged region in this sheet (or candidateRegion is already merged in this sheet)
*/
private void validateMergedRegions(CellRangeAddress candidateRegion) {
for (final CellRangeAddress existingRegion : getMergedRegions()) {
@ -368,6 +419,39 @@ public class XSSFSheet extends POIXMLDocumentPart implements Sheet {
}
}
/**
* Verify that no merged regions intersect another merged region in this sheet.
*
* @throws IllegalStateException if at least one region intersects with another merged region in this sheet
*/
private void checkForIntersectingMergedRegions() {
final List<CellRangeAddress> regions = getMergedRegions();
final int size = regions.size();
for (int i=0; i < size; i++) {
final CellRangeAddress region = regions.get(i);
for (final CellRangeAddress other : regions.subList(i+1, regions.size())) {
if (region.intersects(other)) {
String msg = "The range " + region.formatAsString() +
" intersects with another merged region " +
other.formatAsString() + " in this sheet";
throw new IllegalStateException(msg);
}
}
}
}
/**
* Verify that merged regions do not intersect multi-cell array formulas and
* no merged regions intersect another merged region in this sheet.
*
* @throws IllegalStateException if region intersects with a multi-cell array formula
* @throws IllegalStateException if at least one region intersects with another merged region in this sheet
*/
public void validateMergedRegions() {
checkForMergedRegionsIntersectingArrayFormulas();
checkForIntersectingMergedRegions();
}
/**
* Adjusts the column width to fit the contents.
*

52
src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java
View File

@ -26,6 +26,8 @@ import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.junit.Assume.assumeTrue;
import java.io.IOException;
import java.util.Arrays;
@ -300,6 +302,54 @@ public final class TestXSSFSheet extends BaseTestSheet {
workbook.close();
}
/**
* bug 58885: checking for overlapping merged regions when
* adding a merged region is safe, but runs in O(n).
* the check for merged regions when adding a merged region
* can be skipped (unsafe) and run in O(1).
*/
@Test
public void addMergedRegionUnsafe() throws IOException {
XSSFWorkbook wb = new XSSFWorkbook();
XSSFSheet sh = wb.createSheet();
CellRangeAddress region1 = CellRangeAddress.valueOf("A1:B2");
CellRangeAddress region2 = CellRangeAddress.valueOf("B2:C3");
CellRangeAddress region3 = CellRangeAddress.valueOf("C3:D4");
CellRangeAddress region4 = CellRangeAddress.valueOf("J10:K11");
assumeTrue(region1.intersects(region2));
assumeTrue(region2.intersects(region3));
sh.addMergedRegionUnsafe(region1);
assertTrue(sh.getMergedRegions().contains(region1));
// adding a duplicate or overlapping merged region should not
// raise an exception with the unsafe version of addMergedRegion.
sh.addMergedRegionUnsafe(region2);
// the safe version of addMergedRegion should throw when trying to add a merged region that overlaps an existing region
assertTrue(sh.getMergedRegions().contains(region2));
try {
sh.addMergedRegion(region3);
fail("Expected IllegalStateException. region3 overlaps already added merged region2.");
} catch (final IllegalStateException e) {
// expected
assertFalse(sh.getMergedRegions().contains(region3));
}
// addMergedRegion should not re-validate previously-added merged regions
sh.addMergedRegion(region4);
// validation methods should detect a problem with previously added merged regions (runs in O(n^2) time)
try {
sh.validateMergedRegions();
fail("Expected validation to fail. Sheet contains merged regions A1:B2 and B2:C3, which overlap at B2.");
} catch (final IllegalStateException e) {
// expected
}
wb.close();
}
@Test
public void setDefaultColumnStyle() throws IOException {
XSSFWorkbook workbook = new XSSFWorkbook();
@ -1901,4 +1951,4 @@ public final class TestXSSFSheet extends BaseTestSheet {
assertEquals("B2:D4", ignoredErrors.get(IgnoredErrorType.EVALUATION_ERROR).iterator().next().formatAsString());
workbook.close();
}
}
}