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Josh Cummings suggestions: Package renamed and Benchmark using JMH
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+65
-32
lines changed

4 files changed

+65
-32
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core-java-modules/core-java-11/src/test/java/com/baeldung/pattern/PatternJava11UnitTest.java renamed to core-java-modules/core-java-11/src/test/java/com/baeldung/patternreuse/PatternJava11UnitTest.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
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package com.baeldung.pattern;
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package com.baeldung.patternreuse;
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import org.junit.jupiter.api.Test;
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‎core-java-modules/core-java-text/pom.xml‎

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@@ -13,6 +13,19 @@
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<relativePath>../../parent-java</relativePath>
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</parent>
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<dependencies>
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<dependency>
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<groupId>org.openjdk.jmh</groupId>
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<artifactId>jmh-core</artifactId>
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<version>${jmh-core.version}</version>
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</dependency>
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<dependency>
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<groupId>org.openjdk.jmh</groupId>
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<artifactId>jmh-generator-annprocess</artifactId>
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<version>${jmh-core.version}</version>
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</dependency>
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</dependencies>
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<build>
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<finalName>core-java-text</finalName>
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<resources>

core-java-modules/core-java-text/src/main/java/com/baeldung/pattern/PatternPerformanceComparison.java renamed to core-java-modules/core-java-text/src/main/java/com/baeldung/patternreuse/PatternPerformanceComparison.java

Lines changed: 50 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -1,68 +1,88 @@
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package com.baeldung.pattern;
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package com.baeldung.patternreuse;
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3-
import java.time.Duration;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.runner.RunnerException;
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import java.io.IOException;
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import java.time.Instant;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.concurrent.TimeUnit;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.MILLISECONDS)
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@Fork(value = 1, warmups = 1)
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@Warmup(iterations = 5)
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@State(Scope.Benchmark)
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public class PatternPerformanceComparison {
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private static final String PATTERN = "\\d*[02468]";
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private static List<String> values;
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15-
public static void main(String[] args) {
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loadValues();
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private static Matcher matcherFromPreCompiledPattern;
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private static Pattern preCompiledPattern;
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// 5_000_000 Pattern objects created
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// 5_000_000 Matcher objects created
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Instant start = Instant.now();
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public static void main(String[] args) throws IOException, RunnerException {
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org.openjdk.jmh.Main.main(args);
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}
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@Benchmark
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public void matcherFromPreCompiledPatternResetMatches() {
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//With pre-compiled pattern and reusing the matcher
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// 1 Pattern object created
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// 1 Matcher objects created
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for (String value : values) {
22-
value.matches(PATTERN);
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matcherFromPreCompiledPattern.reset(value).matches();
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}
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System.out.println(Duration.between(start, Instant.now()).toMillis() + "ms -> String.matchs(regex)");
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}
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26-
// Above approach "value.matches(PATTERN)" makes this internally
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// 5_000_000 Pattern objects created
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@Benchmark
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public void preCompiledPatternMatcherMatches() {
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// With pre-compiled pattern
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// 1 Pattern object created
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// 5_000_000 Matcher objects created
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start = Instant.now();
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for (String value : values) {
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Pattern.matches(PATTERN, value);
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preCompiledPattern.matcher(value).matches();
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}
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System.out.println(Duration.between(start, Instant.now()).toMillis() + "ms -> Pattern.matches(regex, charSequence)");
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}
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@Benchmark
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public void patternCompileMatcherMatches() {
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// Above approach "Pattern.matches(PATTERN, value)" makes this internally
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// 5_000_000 Pattern objects created
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// 5_000_000 Matcher objects created
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start = Instant.now();
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for (String value : values) {
4057
Pattern.compile(PATTERN).matcher(value).matches();
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}
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System.out.println(Duration.between(start, Instant.now()).toMillis() + "ms -> Pattern.compile(regex).matcher(charSequence).matches()");
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}
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// With pre-compiled pattern
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// 1 Pattern object created
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@Benchmark
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public void patternMatches() {
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// Above approach "value.matches(PATTERN)" makes this internally
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// 5_000_000 Pattern objects created
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// 5_000_000 Matcher objects created
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Pattern preCompiledPattern = Pattern.compile(PATTERN);
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start = Instant.now();
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for (String value : values) {
50-
preCompiledPattern.matcher(value).matches();
67+
Pattern.matches(PATTERN, value);
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}
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System.out.println(Duration.between(start, Instant.now()).toMillis() + "ms -> preCompiledPattern.matcher(value).matches()");
69+
}
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//With pre-compiled pattern and reusing the matcher
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// 1 Pattern object created
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// 1 Matcher objects created
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Matcher matcherFromPreCompiledPattern = preCompiledPattern.matcher("");
58-
start = Instant.now();
71+
@Benchmark
72+
public void stringMatchs() {
73+
// 5_000_000 Pattern objects created
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// 5_000_000 Matcher objects created
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Instant start = Instant.now();
5976
for (String value : values) {
60-
matcherFromPreCompiledPattern.reset(value).matches();
77+
value.matches(PATTERN);
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}
62-
System.out.println(Duration.between(start, Instant.now()).toMillis() + "ms -> matcherFromPreCompiledPattern.reset(value).matches()");
6379
}
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65-
private static void loadValues() {
81+
@Setup()
82+
public void setUp() {
83+
preCompiledPattern = Pattern.compile(PATTERN);
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matcherFromPreCompiledPattern = preCompiledPattern.matcher("");
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values = new ArrayList<>();
6787
for (int x = 1; x <= 5_000_000; x++) {
6888
values.add(String.valueOf(x));

core-java-modules/core-java-text/src/test/java/com/baeldung/pattern/PatternUnitTest.java renamed to core-java-modules/core-java-text/src/test/java/com/baeldung/patternreuse/PatternUnitTest.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
package com.baeldung.pattern;
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package com.baeldung.patternreuse;
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import org.junit.jupiter.api.Test;
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