Adds support for validating regular expressions (#706)

Co-authored-by: fdutton <fdutton@noreply>

Author: fdutton

src/main/java/com/networknt/schema/JsonMetaSchema.java

@@ -17,6 +17,7 @@
 package com.networknt.schema;
 
 import com.fasterxml.jackson.databind.JsonNode;
+import com.networknt.schema.format.RegexFormat;
 import com.networknt.schema.format.TimeFormat;
 import com.networknt.schema.utils.StringUtils;
 import org.slf4j.Logger;
@@ -91,6 +92,7 @@ static PatternFormat pattern(String name, String regex) {
         COMMON_BUILTIN_FORMATS.add(pattern("phone", "^\\+(?:[0-9] ?){6,14}[0-9]$"));
         COMMON_BUILTIN_FORMATS.add(pattern("utc-millisec", "^[0-9]+(\\.?[0-9]+)?$"));
         COMMON_BUILTIN_FORMATS.add(pattern("style", "\\s*(.+?):\\s*([^;]+);?"));
+        COMMON_BUILTIN_FORMATS.add(new RegexFormat());
     }
 
     public static class Builder {

src/main/java/com/networknt/schema/format/RegexFormat.java

@@ -0,0 +1,42 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.networknt.schema.format;
+
+import com.networknt.schema.AbstractFormat;
+
+import java.util.regex.Pattern;
+import java.util.regex.PatternSyntaxException;
+
+/**
+ * Validates that a value is a valid regex.
+ */
+public class RegexFormat extends AbstractFormat {
+
+    public RegexFormat() {
+        super("regex", "must be a valid regex");
+    }
+
+    @Override
+    public boolean matches(String value) {
+        if (null == value) return true;
+        try {
+            Pattern.compile(value);
+            return true;
+
+        } catch (PatternSyntaxException e) {
+            return false;
+        }
+    }
+
+}

src/test/java/com/networknt/schema/JsonSchemaTestSuiteTest.java

@@ -87,11 +87,9 @@ private void disableV202012Tests() {
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/iri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/iri.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/json-pointer.json"));
-        disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/regex.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/relative-json-pointer.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/uri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/uri-template.json"));
-        disabled.add(Paths.get("src/test/suite/tests/draft2020-12/optional/format/uri.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/ref.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/refRemote.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2020-12/type.json"));
@@ -114,7 +112,6 @@ private void disableV201909Tests() {
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/iri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/iri.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/json-pointer.json"));
-        disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/regex.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/relative-json-pointer.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/uri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft2019-09/optional/format/uri-template.json"));
@@ -141,11 +138,9 @@ private void disableV7Tests() {
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/iri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/iri.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/json-pointer.json"));
-        disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/regex.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/relative-json-pointer.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/uri-reference.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/uri-template.json"));
-        disabled.add(Paths.get("src/test/suite/tests/draft7/optional/format/uri.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/ref.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/refRemote.json"));
         disabled.add(Paths.get("src/test/suite/tests/draft7/type.json"));