From 7bcfc9b3d0b57db0e759255925002514e6e4062d Mon Sep 17 00:00:00 2001
From: "andre.cruz" <andre.cruz@feedzai.com>
Date: Tue, 24 May 2022 14:58:38 +0100
Subject: [PATCH] added a regex validator for FreeTextFieldType

---
 .../fieldtype/FreeTextFieldType.java          | 29 ++++++++++++++++++-
 .../fieldtype/FreeTextFieldTypeTest.java      | 24 ++++++++++++++-
 2 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/openml-api/src/main/java/com/feedzai/openml/provider/descriptor/fieldtype/FreeTextFieldType.java b/openml-api/src/main/java/com/feedzai/openml/provider/descriptor/fieldtype/FreeTextFieldType.java
index ecc3fc1..df55430 100644
--- a/openml-api/src/main/java/com/feedzai/openml/provider/descriptor/fieldtype/FreeTextFieldType.java
+++ b/openml-api/src/main/java/com/feedzai/openml/provider/descriptor/fieldtype/FreeTextFieldType.java
@@ -22,6 +22,7 @@
 
 import java.util.Objects;
 import java.util.Optional;
+import java.util.regex.Pattern;
 
 /**
  * A concrete implementation of a {@link ModelParameterType} for parameters whose values are textual.
@@ -36,18 +37,44 @@ public class FreeTextFieldType implements ModelParameterType {
      */
     private final String defaultValue;
 
+    /**
+     * A regular expression defining a valid input.
+     */
+    private final String validRegex;
+
     /**
      * Creates a new instance of this class.
      *
      * @param defaultValue  The default value.
      */
     public FreeTextFieldType(final String defaultValue) {
+        this(defaultValue, null);
+    }
+
+    /**
+     * Creates a new instance of this class.
+     *
+     * @param defaultValue  The default value.
+     * @param validRegex    A regex that matches valid inputs.
+     */
+    public FreeTextFieldType(final String defaultValue, final String validRegex) {
         this.defaultValue = Preconditions.checkNotNull(defaultValue, "defaultValue can't be null.");
+        this.validRegex = validRegex;
     }
 
     @Override
     public Optional<ParamValidationError> validate(final String parameterName, final String parameterValue) {
-        return Optional.empty();
+        if (this.validRegex == null)
+            return Optional.empty();
+
+        boolean inputIsValid = Pattern.matches(this.validRegex, parameterValue);
+        if (inputIsValid) {
+            return Optional.empty();
+        } else {
+            String reason = "Should match the following regex: " + this.validRegex;
+
+            return Optional.of(new ParamValidationError(parameterName, parameterValue, reason));
+        }
     }
 
     /**
diff --git a/openml-api/src/test/java/com/feedzai/openml/provider/fieldtype/FreeTextFieldTypeTest.java b/openml-api/src/test/java/com/feedzai/openml/provider/fieldtype/FreeTextFieldTypeTest.java
index 1ecaa20..fda3025 100644
--- a/openml-api/src/test/java/com/feedzai/openml/provider/fieldtype/FreeTextFieldTypeTest.java
+++ b/openml-api/src/test/java/com/feedzai/openml/provider/fieldtype/FreeTextFieldTypeTest.java
@@ -31,7 +31,7 @@
 public class FreeTextFieldTypeTest extends AbstractConfigFieldTypeTest<FreeTextFieldType> {
 
     /**
-     * Tests the {@link FreeTextFieldType#validate(String, String)} method.
+     * Tests the {@link FreeTextFieldType#validate(String, String)} method with no regex validator string.
      */
     @Test
     public void validate() {
@@ -43,6 +43,28 @@ public void validate() {
         assertValidationResult(fieldType, "param2", "some string", false);
     }
 
+    /**
+     * Tests the {@link FreeTextFieldType#validate(String, String)} method using the regex validator constructor.
+     */
+    @Test
+    public void validateRegex() {
+        final FreeTextFieldType fieldType = new FreeTextFieldType("1", "^((\\d+(\\.\\d*)?,)*(\\d+(\\.\\d*)?))$");
+
+        // Test valid inputs
+        assertValidationResult(fieldType, "param0", "1", false);
+        assertValidationResult(fieldType, "param0", "1.", false);
+        assertValidationResult(fieldType, "param1", "1.2", false);
+        assertValidationResult(fieldType, "param0", "1.,2", false);
+        assertValidationResult(fieldType, "param2", "1.2,3,4.5", false);
+        assertValidationResult(fieldType, "param3", "1,2,3.4", false);
+
+        // Test invalid inputs
+        assertValidationResult(fieldType, "param4", "", true);
+        assertValidationResult(fieldType, "param5", "1,", true);
+        assertValidationResult(fieldType, "param6", ",1", true);
+        assertValidationResult(fieldType, "param6", "1.2,3.,", true);
+    }
+
     /**
      * Checks the default value method.
      */