Corrects Java's failure to match an end anchor when immediately preceded by a quantifier. (#815)

Resolves #814

Co-authored-by: Faron Dutton <[email protected]>

Author: fdutton

src/main/java/com/networknt/schema/regex/JDKRegularExpression.java

@@ -9,9 +9,19 @@ class JDKRegularExpression implements RegularExpression {
     private final boolean hasEndAnchor;
 
     JDKRegularExpression(String regex) {
-        this.pattern = Pattern.compile(regex);
+        // The patterns in JSON Schema are not implicitly anchored so we must
+        // use Matcher.find(). However, this method does not honor the end
+        // anchor when immediately preceded by a quantifier (e.g., ?, *, +).
+        // To make this work in all cases, we wrap the pattern in a group. 
         this.hasStartAnchor = '^' == regex.charAt(0);
         this.hasEndAnchor = '$' == regex.charAt(regex.length() - 1);
+        String pattern = regex;
+        if (this.hasEndAnchor) {
+            pattern = pattern.substring(this.hasStartAnchor ? 1 : 0, pattern.length() - 1);
+            pattern = '(' + pattern + ")$";
+            if (this.hasStartAnchor) pattern = '^' + pattern;
+        }
+        this.pattern = Pattern.compile(pattern);
     }
 
     @Override

src/test/java/com/networknt/schema/regex/Issue814Test.java

@@ -0,0 +1,47 @@
+package com.networknt.schema.regex;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class Issue814Test {
+
+    @Test
+    void jdkTypePattern() {
+        JDKRegularExpression ex = new JDKRegularExpression("^list|date|time|string|enum|int|double|long|boolean|number$");
+        assertTrue(ex.matches("list"));
+        assertTrue(ex.matches("string"));
+        assertTrue(ex.matches("boolean"));
+        assertTrue(ex.matches("number"));
+        assertTrue(ex.matches("enum"));
+    }
+
+    @Test
+    void jdkOptionsPattern() {
+        JDKRegularExpression ex = new JDKRegularExpression("^\\d*|[a-zA-Z_]+$");
+        assertTrue(ex.matches("external"));
+        assertTrue(ex.matches("external_gte"));
+        assertTrue(ex.matches("force"));
+        assertTrue(ex.matches("internal"));
+    }
+
+    @Test
+    void joniTypePattern() {
+        JoniRegularExpression ex = new JoniRegularExpression("^list|date|time|string|enum|int|double|long|boolean|number$");
+        assertTrue(ex.matches("list"));
+        assertTrue(ex.matches("string"));
+        assertTrue(ex.matches("boolean"));
+        assertTrue(ex.matches("number"));
+        assertTrue(ex.matches("enum"));
+    }
+
+    @Test
+    void joniOptionsPattern() {
+        JoniRegularExpression ex = new JoniRegularExpression("^\\d*|[a-zA-Z_]+$");
+        assertTrue(ex.matches("internal"));
+        assertTrue(ex.matches("external"));
+        assertTrue(ex.matches("external_gte"));
+        assertTrue(ex.matches("force"));
+    }
+
+}