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commit f10f164c61423158261b49e7db8f01fe92441150 Author: Dominik Stadler <[email protected]> AuthorDate: Sun Nov 7 07:42:38 2021 +0100 Add a microBenchmark for replacing strings It shows that Java 11 improves a lot and no custom string-replace is necessary any more when using this version --- .../org/apache/poi/integration/TestXLSX2CSV.java | 68 +++++++++++++++++++++- 1 file changed, 66 insertions(+), 2 deletions(-) diff --git a/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java b/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java index 0867f12b81..912890d458 100644 --- a/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java +++ b/poi-examples/src/test/java/org/apache/poi/integration/TestXLSX2CSV.java @@ -33,8 +33,11 @@ import org.apache.poi.openxml4j.opc.PackageAccess; import org.apache.poi.xssf.XSSFTestDataSamples; import org.junit.jupiter.api.AfterEach; import org.junit.jupiter.api.BeforeEach; +import org.junit.jupiter.api.Disabled; import org.junit.jupiter.api.Test; +import net.bytebuddy.utility.RandomString; + public class TestXLSX2CSV { private PrintStream err; private final UnsynchronizedByteArrayOutputStream errorBytes = UnsynchronizedByteArrayOutputStream.builder().get(); @@ -130,7 +133,68 @@ public class TestXLSX2CSV { assertEquals("", errorOutput); String output = outputBytes.toString(StandardCharsets.UTF_8); - assertTrue(output.contains("\"Lorem\",111,,,"), "Had: " + output); - assertTrue(output.contains(",\"hello, xssf\",,\"hello, xssf\","), "Had: " + output); + assertTrue(output.contains("\"Lorem\",111,,,"), "Had: " + output); + assertTrue(output.contains(",\"hello, xssf\",,\"hello, xssf\","), "Had: " + output); } + + @Disabled("Used for local micro-benchmarking") + @Test + public void microBenchmark() { + checkReplace("str"); + checkReplace("str.123"); + checkReplace("str.123,"); + checkReplace("str,,,.123,,,,"); + for (int i = 0; i < 1000;i++) { + checkReplace(RandomString.make(20)); + } + + for (int i = 0;i < 10;i++) { + long start = System.currentTimeMillis(); + String str = RandomString.make(100) + "\"\"" + RandomString.make(100) + "\"\"" + RandomString.make(100); + String expected = str.replace("\"", "\"\""); + for (int j = 0;j < 300000;j++) { + //assertEquals(expected, replaceString(str, "\"", "\"\"")); + assertEquals(expected, replaceDirect(str, "\"", "\"\"")); + } + + System.out.println(" , " + (System.currentTimeMillis() - start)); + } + + // Java 8: replaceString: 1001, 921, 1264, 1019, 1258, 990, 1089, 1430, 1153, 907 + // Java 8: replaceDirect: 375, 282, 240, 246, 264, 271, 258, 250, 263, 259 + // Java 11: replaceString: 510, 218, 202, 205, 202, 198, 202, 198, 208, 201 + // Java 11: replaceDirect: 384, 228, 204, 201, 201, 200, 206, 196, 200, 200 + // + // => On Java 8, a custom implementation would make sense, however on Java 9 + // String.replace() was optimized so that it does not make any difference + // anymore! + } + + private void checkReplace(String orig) { + assertEquals(replaceString(orig, ",", "."), replaceDirect(orig, ",", "."), + "Did have a difference with " + orig); + } + + public static String replaceString(String originalStr, String oldStr, String newStr) { + return originalStr.replace(oldStr, newStr); + } + + public static String replaceDirect(String originalStr, String oldStr, String newStr) { + int p = originalStr.indexOf(oldStr); + if (p == -1) { + return originalStr; + } else { + StringBuilder result = new StringBuilder(); + result.append(originalStr, 0, p); + result.append(newStr); + int q = p + oldStr.length(); + while ((p = originalStr.indexOf(oldStr, q)) != -1) { + result.append(originalStr, q, p); + result.append(newStr); + q = p + oldStr.length(); + } + result.append(originalStr, q, originalStr.length()); + return result.toString(); + } + } } --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
