CLEANUP: Replace System.out with Proper SLF4J Logging

Replace all System.out console output in production code with proper SLF4J logging:

PROVIDER REGISTRATION MESSAGES (7 files):
• AttributeTypesMetaDataProvider: System.out → log.info
• CoreTypeMetaDataProvider: System.out → log.info
• FieldTypesMetaDataProvider: System.out → log.info
• KeyTypesMetaDataProvider: System.out → log.info
• ValidatorTypesMetaDataProvider: System.out → log.info
• OMMetaDataProvider: System.out → log.info

DEBUG MESSAGES (1 file):
• ExpressionParser: System.out → log.debug for parsing trace messages

TECHNICAL IMPROVEMENTS:
• Added SLF4J Logger declarations to all affected classes
• Used parameterized logging for better performance: log.debug("{} {}", var1, var2)
• Maintained message content while improving logging framework consistency
• Test files and example applications retain System.out (appropriate for demonstrations)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: dmealing

metadata/src/main/java/com/draagon/meta/attr/AttributeTypesMetaDataProvider.java

@@ -2,6 +2,8 @@
 
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Attribute Types MetaData provider that registers all concrete attribute type implementations.
@@ -29,6 +31,8 @@
  */
 public class AttributeTypesMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(AttributeTypesMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // FIRST: Register the base attribute type that all others inherit from
@@ -44,7 +48,7 @@ public void registerTypes(MetaDataRegistry registry) {
         ClassAttribute.registerTypes(registry);
         PropertiesAttribute.registerTypes(registry);
 
-        System.out.println("Info: Attribute types registered via provider");
+        log.info("Attribute types registered via provider");
     }
 
     @Override

metadata/src/main/java/com/draagon/meta/core/CoreTypeMetaDataProvider.java

@@ -3,6 +3,8 @@
 import com.draagon.meta.MetaData;
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Core Type MetaData provider that registers the fundamental base types.
@@ -24,12 +26,14 @@
  */
 public class CoreTypeMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(CoreTypeMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // Register the fundamental metadata.base type that all others inherit from
         MetaData.registerTypes(registry);
 
-        System.out.println("Info: Core base types registered via provider");
+        log.info("Core base types registered via provider");
     }
 
     @Override

metadata/src/main/java/com/draagon/meta/field/FieldTypesMetaDataProvider.java

@@ -2,6 +2,8 @@
 
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Field Types MetaData provider that registers all concrete field type implementations.
@@ -31,6 +33,8 @@
  */
 public class FieldTypesMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(FieldTypesMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // FIRST: Register the base field type that all others inherit from
@@ -48,7 +52,7 @@ public void registerTypes(MetaDataRegistry registry) {
         ByteField.registerTypes(registry);
         ShortField.registerTypes(registry);
 
-        System.out.println("Info: Field types registered via provider");
+        log.info("Field types registered via provider");
     }
 
     @Override

metadata/src/main/java/com/draagon/meta/key/KeyTypesMetaDataProvider.java

@@ -2,6 +2,8 @@
 
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Key Types MetaData provider that registers all concrete key type implementations.
@@ -24,6 +26,8 @@
  */
 public class KeyTypesMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(KeyTypesMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // FIRST: Register the base key type that all others inherit from
@@ -34,7 +38,7 @@ public void registerTypes(MetaDataRegistry registry) {
         ForeignKey.registerTypes(registry);
         SecondaryKey.registerTypes(registry);
 
-        System.out.println("Info: Key types registered via provider");
+        log.info("Key types registered via provider");
     }
 
     @Override

metadata/src/main/java/com/draagon/meta/validator/ValidatorTypesMetaDataProvider.java

@@ -2,6 +2,8 @@
 
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * Validator Types MetaData provider that registers all concrete validator type implementations.
@@ -26,6 +28,8 @@
  */
 public class ValidatorTypesMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(ValidatorTypesMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // FIRST: Register the base validator type that all others inherit from
@@ -38,7 +42,7 @@ public void registerTypes(MetaDataRegistry registry) {
         NumericValidator.registerTypes(registry);
         ArrayValidator.registerTypes(registry);
 
-        System.out.println("Info: Validator types registered via provider");
+        log.info("Validator types registered via provider");
     }
 
     @Override

om/src/main/java/com/draagon/meta/manager/exp/parser/ExpressionParser.java

@@ -10,9 +10,12 @@
 import com.draagon.meta.field.LongField;
 import com.draagon.meta.field.StringField;
 import com.draagon.meta.manager.exp.Expression;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class ExpressionParser
 {
+  private static final Logger log = LoggerFactory.getLogger(ExpressionParser.class);
   private static ExpressionParser instance = null;
 
   protected class ExpResult
@@ -108,7 +111,7 @@ else if ( c == 'o' && isOr( str, x )){
         //if ( str.charAt( r.getEnd() ) != ')' )
         x = r.getEnd();
 
-        System.out.println( "END: [" + str.charAt( x ) + "] " + str.substring( x ));
+        log.debug("END: [{}] {}", str.charAt(x), str.substring(x));
 
         n = x;
       }
@@ -268,6 +271,6 @@ public static void main( String [] args ) throws ExpressionParseError
     mc.addMetaField( d );
 
     Expression exp = ExpressionParser.getInstance().parse( mc, "( time > = '10/12/2006 14:55' and ( ( id = 5 or name = 'test me!' ) and value <> 20))" );
-    System.out.println( "EXPRESSION: " + exp );
+    log.debug("EXPRESSION: {}", exp);
   }
 }

om/src/main/java/com/draagon/meta/object/managed/OMMetaDataProvider.java

@@ -2,6 +2,8 @@
 
 import com.draagon.meta.registry.MetaDataRegistry;
 import com.draagon.meta.registry.MetaDataTypeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * OM (Object Manager) MetaData provider that registers managed object types.
@@ -22,12 +24,14 @@
  */
 public class OMMetaDataProvider implements MetaDataTypeProvider {
 
+    private static final Logger log = LoggerFactory.getLogger(OMMetaDataProvider.class);
+
     @Override
     public void registerTypes(MetaDataRegistry registry) {
         // Register managed object type
         ManagedMetaObject.registerTypes(registry);
 
-        System.out.println("Info: OM managed types registered via provider");
+        log.info("OM managed types registered via provider");
     }
 
     @Override