move regex module from existing module to core-java-regex module

2020-02-05 19:39:20 +05:30
parent 67f38293d8
commit fa6647a95e
11 changed files with 12 additions and 12 deletions
@@ -0,0 +1,92 @@
+package com.baeldung.patternreuse;
+
+import org.openjdk.jmh.annotations.*;
+import org.openjdk.jmh.infra.Blackhole;
+import org.openjdk.jmh.runner.RunnerException;
+
+import java.io.IOException;
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@BenchmarkMode(Mode.AverageTime)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Fork(value = 1, warmups = 1)
+@Warmup(iterations = 5)
+@State(Scope.Benchmark)
+public class PatternPerformanceComparison {
+
+    private static final String PATTERN = "\\d*[02468]";
+    private static List<String> values;
+
+    private static Matcher matcherFromPreCompiledPattern;
+    private static Pattern preCompiledPattern;
+
+    public static void main(String[] args) throws IOException, RunnerException {
+        org.openjdk.jmh.Main.main(args);
+    }
+
+    @Benchmark
+    public void matcherFromPreCompiledPatternResetMatches(Blackhole bh) {
+        //With pre-compiled pattern and reusing the matcher
+        // 1 Pattern object created
+        // 1 Matcher objects created
+        for (String value : values) {
+            bh.consume(matcherFromPreCompiledPattern.reset(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void preCompiledPatternMatcherMatches(Blackhole bh) {
+        // With pre-compiled pattern
+        // 1         Pattern object created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(preCompiledPattern.matcher(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void patternCompileMatcherMatches(Blackhole bh) {
+        // Above approach "Pattern.matches(PATTERN, value)" makes this internally
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(Pattern.compile(PATTERN).matcher(value).matches());
+        }
+    }
+
+    @Benchmark
+    public void patternMatches(Blackhole bh) {
+        // Above approach "value.matches(PATTERN)" makes this internally
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        for (String value : values) {
+            bh.consume(Pattern.matches(PATTERN, value));
+        }
+    }
+
+    @Benchmark
+    public void stringMatchs(Blackhole bh) {
+        // 5_000_000 Pattern objects created
+        // 5_000_000 Matcher objects created
+        Instant start = Instant.now();
+        for (String value : values) {
+            bh.consume(value.matches(PATTERN));
+        }
+    }
+
+    @Setup()
+    public void setUp() {
+        preCompiledPattern = Pattern.compile(PATTERN);
+        matcherFromPreCompiledPattern = preCompiledPattern.matcher("");
+
+        values = new ArrayList<>();
+        for (int x = 1; x <= 5_000_000; x++) {
+            values.add(String.valueOf(x));
+        }
+    }
+}
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>