[Java] Improve cucumber expression creation performance

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Fixed
+- [Java] Improve cucumber expression creation performance ([#202](https://github.com/cucumber/cucumber-expressions/pull/202))
+
 ## [16.1.1] - 2022-12-08
 ### Fixed
 - [Java] Improve expression creation performance ([#187](https://github.com/cucumber/cucumber-expressions/pull/187), [#189](https://github.com/cucumber/cucumber-expressions/pull/189))

java/src/main/java/io/cucumber/cucumberexpressions/CucumberExpression.java

@@ -24,7 +24,27 @@
 
 @API(status = API.Status.STABLE)
 public final class CucumberExpression implements Expression {
-    private static final Pattern ESCAPE_PATTERN = Pattern.compile("[\\\\^\\[({$.|?*+})\\]]");
+    /**
+     * List of characters to be escaped.
+     * The last char is '}' with index 125, so we need only 126 characters.
+     */
+    private static final boolean[] CHAR_TO_ESCAPE = new boolean[126];
+    static {
+        CHAR_TO_ESCAPE['^'] = true;
+        CHAR_TO_ESCAPE['$'] = true;
+        CHAR_TO_ESCAPE['['] = true;
+        CHAR_TO_ESCAPE[']'] = true;
+        CHAR_TO_ESCAPE['('] = true;
+        CHAR_TO_ESCAPE[')'] = true;
+        CHAR_TO_ESCAPE['{'] = true;
+        CHAR_TO_ESCAPE['}'] = true;
+        CHAR_TO_ESCAPE['.'] = true;
+        CHAR_TO_ESCAPE['|'] = true;
+        CHAR_TO_ESCAPE['?'] = true;
+        CHAR_TO_ESCAPE['*'] = true;
+        CHAR_TO_ESCAPE['+'] = true;
+        CHAR_TO_ESCAPE['\\'] = true;
+    }
     private final List<ParameterType<?>> parameterTypes = new ArrayList<>();
     private final String source;
     private final TreeRegexp treeRegexp;
@@ -61,9 +81,18 @@ private String rewriteToRegex(Node node) {
     }
 
     private static String escapeRegex(String text) {
-        return ESCAPE_PATTERN.matcher(text).replaceAll("\\\\$0");
+        int length = text.length();
+        StringBuilder sb = new StringBuilder(length * 2); // prevent resizes
+        int maxChar = CHAR_TO_ESCAPE.length;
+        for (int i = 0; i < length; i++) {
+            char currentChar = text.charAt(i);
+            if (currentChar < maxChar && CHAR_TO_ESCAPE[currentChar]) {
+                sb.append('\\');
+            }
+            sb.append(currentChar);
+        }
+        return sb.toString();
     }
-
 
     private String rewriteOptional(Node node) {
         assertNoParameters(node, astNode -> createParameterIsNotAllowedInOptional(astNode, source));

java/src/test/java/io/cucumber/cucumberexpressions/CucumberExpressionTest.java

@@ -12,6 +12,8 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.lang.reflect.Type;
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -192,4 +194,34 @@ private List<?> match(String expr, String text, ParameterTypeRegistry parameterT
             return list;
         }
     }
+
+    @Test
+    void escape_all_regexp_characters() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+        assertEquals("\\^\\$\\[\\]\\(\\)\\{\\}\\.\\|\\?\\*\\+\\\\", delegateEscapeRegex("^$[](){}.|?*+\\"));
+    }
+
+    @Test
+    void escape_escaped_regexp_characters() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+        assertEquals("\\^\\$\\[\\]\\\\\\(\\\\\\)\\{\\}\\\\\\\\\\.\\|\\?\\*\\+", delegateEscapeRegex("^$[]\\(\\){}\\\\.|?*+"));
+    }
+
+
+    @Test
+    void do_not_escape_when_there_is_nothing_to_escape() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+        assertEquals("dummy", delegateEscapeRegex("dummy"));
+    }
+
+    @Test
+    void escapeRegex_gives_no_error_for_unicode_characters() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
+        assertEquals("🥒", delegateEscapeRegex("🥒"));
+    }
+
+    private String delegateEscapeRegex(String expression) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
+        // this delegate is used to test the private method `escapeRegex(String)`
+        ParameterTypeRegistry context = new ParameterTypeRegistry(Locale.ENGLISH);
+        Method escapeRegex = CucumberExpression.class.getDeclaredMethod("escapeRegex", String.class);
+        escapeRegex.setAccessible(true);
+        return (String)escapeRegex.invoke(new CucumberExpression("", context), expression);
+    }
+
 }