diff --git a/valdr-bean-validation/src/main/java/com/github/valdr/ConstraintAttributes.java b/valdr-bean-validation/src/main/java/com/github/valdr/ConstraintAttributes.java
index c315f08..d9dde84 100644
--- a/valdr-bean-validation/src/main/java/com/github/valdr/ConstraintAttributes.java
+++ b/valdr-bean-validation/src/main/java/com/github/valdr/ConstraintAttributes.java
@@ -40,6 +40,14 @@ public int size() {
   public Object put(String key, Object value) {
     return map.put(key, value);
   }
+  
+  public Object remove(String key) {
+      return map.remove(key);
+  }
+  
+  public Object get(String key) {
+      return map.get(key);
+  }
 
   private void removeUnusedAttributes(Map<String, Object> annotationAttributes) {
     Iterator<String> it = annotationAttributes.keySet().iterator();
diff --git a/valdr-bean-validation/src/main/java/com/github/valdr/decorator/PatternDecorator.java b/valdr-bean-validation/src/main/java/com/github/valdr/decorator/PatternDecorator.java
index 738f904..12d0c53 100644
--- a/valdr-bean-validation/src/main/java/com/github/valdr/decorator/PatternDecorator.java
+++ b/valdr-bean-validation/src/main/java/com/github/valdr/decorator/PatternDecorator.java
@@ -1,10 +1,11 @@
 package com.github.valdr.decorator;
 
-import com.github.valdr.ConstraintAttributes;
-
+import java.util.HashMap;
 import java.util.Map;
 import java.util.Set;
 
+import com.github.valdr.ConstraintAttributes;
+
 /**
  * Decorates the map of attributes of the {@link javax.validation.constraints.Pattern} constraint.
  */
@@ -31,12 +32,15 @@ public PatternDecorator(ConstraintAttributes decoratee) {
   @Override
   public Set<Map.Entry<String, Object>> entrySet() {
     Set<Map.Entry<String, Object>> entrySet = getDecoratee().entrySet();
+    Map<String, Object> result = new HashMap<>();
     for (Map.Entry<String, Object> entry : entrySet) {
       if ("regexp".equals(entry.getKey())) {
-        entry.setValue(javaToJavaScriptRegexpPattern(entry));
+        result.put("value", javaToJavaScriptRegexpPattern(entry));
+      } else {
+          result.put(entry.getKey(), entry.getValue());
       }
     }
-    return entrySet;
+    return result.entrySet();
   }
 
   private String javaToJavaScriptRegexpPattern(Map.Entry<String, Object> entry) {