Add support for @Pattern annotations in String schemas

src/main/java/com/fasterxml/jackson/module/jsonSchema/customProperties/ValidationSchemaFactoryWrapper.java

@@ -81,6 +81,7 @@ private JsonSchema addValidationConstraints(JsonSchema schema, BeanProperty prop
             StringSchema stringSchema = schema.asStringSchema();
             stringSchema.setMaxLength(constraintResolver.getStringMaxLength(prop));
             stringSchema.setMinLength(constraintResolver.getStringMinLength(prop));
+            stringSchema.setPattern(constraintResolver.getStringPattern(prop));
         }
         return schema;
     }

src/main/java/com/fasterxml/jackson/module/jsonSchema/validation/AnnotationConstraintResolver.java

@@ -63,4 +63,13 @@ public Integer getStringMaxLength(BeanProperty prop) {
     public Integer getStringMinLength(BeanProperty prop) {
         return getMinSize(prop);
     }
+
+    @Override
+    public String getStringPattern(final BeanProperty prop) {
+        Pattern patternAnnotation = prop.getAnnotation(Pattern.class);
+        if (patternAnnotation != null) {
+            return patternAnnotation.regexp();
+        }
+        return null;
+    }
 }

src/main/java/com/fasterxml/jackson/module/jsonSchema/validation/ValidationConstraintResolver.java

@@ -19,4 +19,5 @@ public interface ValidationConstraintResolver {
 
     Integer getStringMinLength(BeanProperty prop);
 
+    String getStringPattern(BeanProperty prop);
 }

src/test/java/com/fasterxml/jackson/module/jsonSchema/ValidationSchemaFactoryWrapperTest.java

@@ -87,6 +87,9 @@ public static class ValidationBean {
         @Size(min = 15, max = 16)
         private String stringWithMinAndMaxSize;
 
+        @Pattern(regexp = "[a-z]+")
+        private String stringWithPattern;
+
         public List<String> getListWithoutConstraints() {
             return listWithoutConstraints;
         }
@@ -222,6 +225,14 @@ public String getStringWithMinAndMaxSize() {
         public void setStringWithMinAndMaxSize(String stringWithMinAndMaxSize) {
             this.stringWithMinAndMaxSize = stringWithMinAndMaxSize;
         }
+
+        public String getStringWithPattern() {
+            return stringWithPattern;
+        }
+
+        public void setStringWithPattern(final String stringWithPattern) {
+            this.stringWithPattern = stringWithPattern;
+        }
     }
 
     /*
@@ -256,6 +267,11 @@ private Object[][] stringTestData() {
                 {"stringWithMinAndMaxSize", 15, 16}};
     }
 
+    private Object[][] stringPatternTestData() {
+        return new Object[][] {{"stringWithPattern", "[a-z]+"},
+                {"stringWithoutConstraints", null}};
+    }
+
     /**
      * Test set validation constraints
      */
@@ -294,6 +310,13 @@ public void testAddingValidationConstraints() throws Exception {
             assertEquals(testCase[1], stringSchema.getMinLength());
             assertEquals(testCase[2], stringSchema.getMaxLength());
         }
+        for (Object[] testCase : stringPatternTestData()) {
+            JsonSchema propertySchema = properties.get(testCase[0]);
+            assertNotNull(propertySchema);
+            assertTrue(propertySchema.isStringSchema());
+            StringSchema stringSchema = propertySchema.asStringSchema();
+            assertEquals(testCase[1], stringSchema.getPattern());
+        }
     }
 
 }