Add support for custom validation callbacks on fields

* Add support for custom validation callbacks on fields

Introduce setCustomValidationCallback to PdmFieldHandle, allowing custom validation logic via user-provided lambdas or functions. The validate() method now invokes this callback if set, in addition to built-in checks. Includes comprehensive unit tests for custom and combined validation scenarios. Backward compatible: default behavior unchanged if no callback is set.

Fwk/AppFwk/cafProjectDataModel/cafPdmCore/cafPdmCore_UnitTests/cafPdmCoreBasicTest.cpp

@@ -12,6 +12,7 @@
 #include "cafPdmReferenceHelper.h"
 #include "cafPdmValueField.h"
 
+#include <memory>
 #include <vector>
 
 class DemoPdmObject : public caf::PdmObjectHandle
@@ -1008,3 +1009,87 @@ TEST( BaseTest, ObjectValidation )
 
     delete customObj;
 }
+
+//--------------------------------------------------------------------------------------------------
+/// Test of custom validation callback
+//--------------------------------------------------------------------------------------------------
+TEST( BaseTest, CustomValidationCallback )
+{
+    class TestObject : public caf::PdmObjectHandle
+    {
+    public:
+        TestObject()
+        {
+            this->addField( &m_value, "value" );
+            this->addField( &m_rangedValue, "rangedValue" );
+        }
+
+        caf::PdmDataValueField<int> m_value;
+        caf::PdmDataValueField<int> m_rangedValue;
+    };
+
+    auto obj = std::make_unique<TestObject>();
+
+    // A field with no callback is valid by default
+    obj->m_value.setValue( 42 );
+    EXPECT_TRUE( obj->m_value.isValid() );
+    EXPECT_TRUE( obj->m_value.validate().isEmpty() );
+
+    // Registering a callback that returns an error string makes the field invalid
+    obj->m_value.setCustomValidationCallback( []() -> QString { return "Custom error"; } );
+    EXPECT_FALSE( obj->m_value.isValid() );
+    EXPECT_EQ( QString( "Custom error" ), obj->m_value.validate() );
+
+    // Registering a callback that returns empty string keeps the field valid
+    obj->m_value.setCustomValidationCallback( []() -> QString { return QString(); } );
+    EXPECT_TRUE( obj->m_value.isValid() );
+    EXPECT_TRUE( obj->m_value.validate().isEmpty() );
+
+    // The callback can access the field value for conditional validation
+    obj->m_value.setCustomValidationCallback(
+        [&obj]() -> QString
+        {
+            if ( obj->m_value.value() % 2 != 0 )
+            {
+                return "Value must be even";
+            }
+            return QString();
+        } );
+
+    obj->m_value.setValue( 4 );
+    EXPECT_TRUE( obj->m_value.isValid() );
+
+    obj->m_value.setValue( 7 );
+    EXPECT_FALSE( obj->m_value.isValid() );
+    EXPECT_EQ( QString( "Value must be even" ), obj->m_value.validate() );
+
+    // Custom callback works alongside range validation (both must pass)
+    obj->m_rangedValue.setRange( 0, 100 );
+    obj->m_rangedValue.setCustomValidationCallback(
+        [&obj]() -> QString
+        {
+            if ( obj->m_rangedValue.value() % 2 != 0 )
+            {
+                return "Value must be even";
+            }
+            return QString();
+        } );
+
+    // Both range and custom pass
+    obj->m_rangedValue.setValue( 50 );
+    EXPECT_TRUE( obj->m_rangedValue.isValid() );
+
+    // Range fails (custom would pass)
+    obj->m_rangedValue.setValue( 150 );
+    EXPECT_FALSE( obj->m_rangedValue.isValid() );
+    EXPECT_TRUE( obj->m_rangedValue.validate().contains( "exceeds maximum" ) );
+
+    // Custom fails (range would pass)
+    obj->m_rangedValue.setValue( 51 );
+    EXPECT_FALSE( obj->m_rangedValue.isValid() );
+    EXPECT_EQ( QString( "Value must be even" ), obj->m_rangedValue.validate() );
+
+    // Both pass
+    obj->m_rangedValue.setValue( 50 );
+    EXPECT_TRUE( obj->m_rangedValue.isValid() );
+}

Fwk/AppFwk/cafProjectDataModel/cafPdmCore/cafPdmDataValueField.h

@@ -259,7 +259,7 @@ QString caf::PdmDataValueField<DataType>::validate() const
             return QString( "Value %1 exceeds maximum %2" ).arg( m_fieldValue ).arg( m_maxValue.value() );
         }
     }
-    return QString();
+    return executeCustomValidation();
 }
 
 } // End of namespace caf

Fwk/AppFwk/cafProjectDataModel/cafPdmCore/cafPdmFieldHandle.cpp

@@ -135,6 +135,26 @@ std::vector<QString> PdmFieldHandle::keywordAliases() const
 //--------------------------------------------------------------------------------------------------
 QString PdmFieldHandle::validate() const
 {
+    return executeCustomValidation();
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+void PdmFieldHandle::setCustomValidationCallback( std::function<QString()> callback )
+{
+    m_customValidationCallback = std::move( callback );
+}
+
+//--------------------------------------------------------------------------------------------------
+///
+//--------------------------------------------------------------------------------------------------
+QString PdmFieldHandle::executeCustomValidation() const
+{
+    if ( m_customValidationCallback )
+    {
+        return m_customValidationCallback();
+    }
     return QString();
 }
 

Fwk/AppFwk/cafProjectDataModel/cafPdmCore/cafPdmFieldHandle.h

@@ -2,6 +2,7 @@
 
 #include "cafPdmBase.h"
 #include <QString>
+#include <functional>
 #include <vector>
 
 namespace caf
@@ -61,9 +62,11 @@ public:
     // Validation
     virtual QString validate() const;
     bool            isValid() const;
+    void            setCustomValidationCallback( std::function<QString()> callback );
 
 protected:
-    bool isInitializedByInitFieldMacro() const { return m_ownerObject != nullptr; }
+    QString executeCustomValidation() const;
+    bool    isInitializedByInitFieldMacro() const { return m_ownerObject != nullptr; }
 
 private:
     PDM_DISABLE_COPY_AND_ASSIGN( PdmFieldHandle );
@@ -77,6 +80,8 @@ private:
     std::vector<QString> m_keywordAliases;
 
     std::vector<std::pair<PdmFieldCapability*, bool>> m_capabilities;
+
+    std::function<QString()> m_customValidationCallback;
 };
 
 //--------------------------------------------------------------------------------------------------

Fwk/AppFwk/cafTests/cafTestApplication/ValidationTest.cpp

@@ -26,18 +26,36 @@ ValidationTestObject::ValidationTestObject()
     m_percentage.uiCapability()->setUiToolTip( "Valid range: 0 to 100%" );
     m_percentage.setRange( 0.0, 100.0 );
 
-    // Count field: minimum value only (>= 0)
+    // Count field: minimum value only (>= 0) and must be even (custom callback)
     CAF_PDM_InitField( &m_count, "count", 0, "Count", "", "", "" );
-    m_count.uiCapability()->setUiToolTip( "Must be non-negative" );
+    m_count.uiCapability()->setUiToolTip( "Must be non-negative and even" );
     m_count.setMinValue( 0 );
+    m_count.setCustomValidationCallback(
+        [this]() -> QString
+        {
+            if ( m_count() % 2 != 0 )
+            {
+                return "Count must be an even number";
+            }
+            return {};
+        } );
 
     // Name field: no validation
     CAF_PDM_InitField( &m_name, "name", QString( "John Doe" ), "Name", "", "", "" );
     m_name.uiCapability()->setUiToolTip( "Free text field" );
 
-    // Email field: no validation (but could add custom validation in validate())
+    // Email field: custom validation callback
     CAF_PDM_InitField( &m_email, "email", QString( "john@example.com" ), "Email", "", "", "" );
-    m_email.uiCapability()->setUiToolTip( "Email address" );
+    m_email.uiCapability()->setUiToolTip( "Email address (must contain @)" );
+    m_email.setCustomValidationCallback(
+        [this]() -> QString
+        {
+            if ( !m_email().isEmpty() && !m_email().contains( "@" ) )
+            {
+                return "Email must contain @ symbol";
+            }
+            return {};
+        } );
 
     // Range field: -100.0 to 100.0
     CAF_PDM_InitField( &m_rangeField, "rangeField", 0.0, "Range Field", "", "", "" );
@@ -54,15 +72,7 @@ std::map<QString, QString> ValidationTestObject::validate( const QString& config
     auto errors = PdmObject::validate( configName );
 
     // Add custom object-level validation
-
+    // Note: email validation is handled by a custom validation callback on the field itself
-    // Email validation (basic)
-    if ( !m_email().isEmpty() )
-    {
-        if ( !m_email().contains( "@" ) )
-        {
-            errors["email"] = "Email must contain @ symbol";
-        }
-    }
 
     // Name validation
     if ( m_name().isEmpty() )
@@ -135,6 +145,7 @@ void ValidationTestObject::performValidation()
     qDebug() << "Age valid:" << m_age.isValid();
     qDebug() << "Percentage valid:" << m_percentage.isValid();
     qDebug() << "Count valid:" << m_count.isValid();
+    qDebug() << "Email valid:" << m_email.isValid();
 
     // Show validation messages
     if ( !m_temperature.isValid() )
@@ -153,4 +164,8 @@ void ValidationTestObject::performValidation()
     {
         qDebug() << "  Count error:" << m_count.validate();
     }
+    if ( !m_email.isValid() )
+    {
+        qDebug() << "  Email error:" << m_email.validate();
+    }
 }