Add isEmpty function to validate that JSON objects are not empty

src/main/java/com/yetanalytics/xapi/model/AbstractActor.java

@@ -79,4 +79,12 @@ protected int countIFIs() {
     }
 
     public abstract boolean isValidAuthority();
+
+    @Override
+    public boolean isEmpty() {
+        return (
+            mbox == null && mbox_sha1sum == null &&
+            openid == null && account == null
+        );
+    }
 }

src/main/java/com/yetanalytics/xapi/model/AbstractObject.java

@@ -7,7 +7,7 @@
 * Abstract Class for serialization and deserialization of xAPI Objects
 */
 @JsonDeserialize(using = AbstractObjectDeserializer.class)
-public class AbstractObject {
+public abstract class AbstractObject implements JSONObject {
 
     private ObjectType objectType;
 
@@ -18,4 +18,6 @@ public void setObjectType(ObjectType objectType) {
         this.objectType = objectType;
     }
 
+    @Override
+    public abstract boolean isEmpty();
 }

src/main/java/com/yetanalytics/xapi/model/Account.java

@@ -3,14 +3,15 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.NotNull;
 
 /**
 * Class representation of the Account Component of the 
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#2424-account-object">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class Account {
+public class Account implements JSONObject {
 
     @NotNull
     private String homePage;
@@ -30,4 +31,10 @@ public String getName() {
     public void setName(String name) {
         this.name = name;
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return homePage == null && name == null;
+    }
 }

src/main/java/com/yetanalytics/xapi/model/Activity.java

@@ -5,6 +5,7 @@
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 
 import jakarta.validation.Valid;
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.NotNull;
 
 /**
@@ -33,4 +34,10 @@ public ActivityDefinition getDefinition() {
     public void setDefinition(ActivityDefinition definition) {
         this.definition = definition;
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return id == null && definition == null;
+    }
 }

src/main/java/com/yetanalytics/xapi/model/ActivityDefinition.java

@@ -5,14 +5,15 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.AssertTrue;
 
 /**
 * Class representation of the Activity Definition Component of the 
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#activity-definition">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class ActivityDefinition {
+public class ActivityDefinition implements JSONObject {
 
     private LangMap name;
     private LangMap description;
@@ -162,6 +163,16 @@ private boolean isNoInteraction() {
         );
     }
 
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return (
+            name == null && description == null &&
+            type == null && moreInfo == null && extensions == null &&
+            interactionType == null && isNoInteraction()
+        );
+    }
+
     @AssertTrue
     public boolean isValidInteractionActivity() {
         if (interactionType == null) {

src/main/java/com/yetanalytics/xapi/model/Agent.java

@@ -4,6 +4,7 @@
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.AssertTrue;
 
 /**
@@ -17,6 +18,12 @@ public class Agent extends AbstractActor {
 
     // Validation
 
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return super.isEmpty();
+    }
+
     /**
      * Assertion that the Agent has only 1 Inverse Functional Identifier (IFI).
      * @return true if the Agent has exactly 1 IFI, false otherwise

src/main/java/com/yetanalytics/xapi/model/Attachment.java

@@ -3,14 +3,15 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.NotNull;
 
 /**
  * Class representation of the Attachment Component of the 
  * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#2411-attachments">9274.1.1 xAPI Specification</a>.
  */
 @JsonInclude(Include.NON_NULL)
-public class Attachment {
+public class Attachment implements JSONObject {
 
     @NotNull
     private String usageType;
@@ -68,5 +69,17 @@ public void setFileUrl(String fileUrl) {
         this.fileUrl = fileUrl;
     }
 
-
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return (
+            usageType == null &&
+            display == null &&
+            description == null &&
+            contentType == null &&
+            length == null &&
+            sha2 == null &&
+            fileUrl == null
+        );
+    }
 }

src/main/java/com/yetanalytics/xapi/model/Context.java

@@ -1,15 +1,18 @@
 package com.yetanalytics.xapi.model;
 
 import java.util.UUID;
+
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
+import jakarta.validation.constraints.AssertFalse;
+
 /**
 * Class representation of the Context Component of the 
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#246-context">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class Context {
+public class Context implements JSONObject {
 
     private UUID registration;
     private AbstractActor instructor;
@@ -76,4 +79,19 @@ public void setExtensions(Extensions extensions) {
         this.extensions = extensions;
     }
 
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return (
+            registration == null &&
+            instructor == null &&
+            team == null &&
+            contextActivities == null &&
+            revision == null &&
+            platform == null &&
+            language == null &&
+            statement == null &&
+            extensions == null
+        );
+    }
 }

src/main/java/com/yetanalytics/xapi/model/ContextActivities.java

@@ -4,6 +4,9 @@
 
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.yetanalytics.xapi.model.deserializers.ContextActivityListDeserializer;
+
+import jakarta.validation.constraints.AssertFalse;
+
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
@@ -12,7 +15,7 @@
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#2462-contextactivities-property">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class ContextActivities {
+public class ContextActivities implements JSONObject {
 
     @JsonDeserialize(using = ContextActivityListDeserializer.class)
     private List<Activity> parent;
@@ -48,4 +51,12 @@ public void setOther(List<Activity> other) {
         this.other = other;
     }
 
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return (
+            parent == null && grouping == null &&
+            category == null && other == null
+        );
+    }
 }

src/main/java/com/yetanalytics/xapi/model/Extensions.java

@@ -13,6 +13,8 @@
 import com.yetanalytics.xapi.model.serializers.ExtensionSerializer;
 import com.yetanalytics.xapi.util.Mapper;
 
+import jakarta.validation.constraints.AssertFalse;
+
 /**
  * A wrapper object for using <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#41-extensions">xAPI Extensions</a>.
  * 
@@ -22,7 +24,7 @@
  */
 @JsonDeserialize(using = ExtensionDeserializer.class)
 @JsonSerialize(using = ExtensionSerializer.class)
-public class Extensions {
+public class Extensions implements JSONObject {
 
     private Map<String,Object> extMap = new HashMap<>();
 
@@ -96,4 +98,10 @@ public Set<String> getKeys() {
     public Map<String, Object> getMap() {
         return extMap;
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return extMap.isEmpty();
+    }
 }

src/main/java/com/yetanalytics/xapi/model/Group.java

@@ -6,6 +6,7 @@
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.AssertTrue;
 
 /**
@@ -48,4 +49,11 @@ public boolean isValidAuthority() {
             )
         );
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        // zero-length member arrays still count as non-empty
+        return super.isEmpty() && member == null;
+    }
 }

src/main/java/com/yetanalytics/xapi/model/InteractionComponent.java

@@ -2,14 +2,15 @@
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
+import jakarta.validation.constraints.AssertFalse;
 import jakarta.validation.constraints.NotNull;
 
 /**
 * Class representation of the Interaction Component of the 
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#interaction-components">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class InteractionComponent {
+public class InteractionComponent implements JSONObject {
 
     @NotNull
     private String id;
@@ -32,5 +33,9 @@ public void setDescription(LangMap description) {
         this.description = description;
     }
 
-
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return id == null && description == null;
+    }
 }

src/main/java/com/yetanalytics/xapi/model/JSONObject.java

@@ -0,0 +1,5 @@
+package com.yetanalytics.xapi.model;
+
+public interface JSONObject {
+    public boolean isEmpty();
+}

src/main/java/com/yetanalytics/xapi/model/LangMap.java

@@ -9,6 +9,8 @@
 import com.yetanalytics.xapi.model.deserializers.LangMapDeserializer;
 import com.yetanalytics.xapi.model.serializers.LangMapSerializer;
 
+import jakarta.validation.constraints.AssertFalse;
+
 /**
  * Java wrapper object for the 
  * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#42-language-maps">xAPI Language Map object</a>.
@@ -18,7 +20,7 @@
  */
 @JsonDeserialize(using = LangMapDeserializer.class)
 @JsonSerialize(using = LangMapSerializer.class)
-public class LangMap {
+public class LangMap implements JSONObject {
 
     private HashMap<String,String> languageHashMap = new HashMap<>();
 
@@ -71,4 +73,10 @@ public Set<String> getLanguageCodes() {
     public Map<String, String> getMap() {
         return languageHashMap;
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return languageHashMap.isEmpty();
+    }
 }

src/main/java/com/yetanalytics/xapi/model/Result.java

@@ -4,13 +4,14 @@
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 
 import jakarta.validation.Valid;
+import jakarta.validation.constraints.AssertFalse;
 
 /**
 * Class representation of the Result component of the 
 * <a href="https://github.com/adlnet/xAPI-Spec/blob/master/xAPI-Data.md#245-result">9274.1.1 xAPI Specification</a>.
 */
 @JsonInclude(Include.NON_NULL)
-public class Result {
+public class Result implements JSONObject {
 
     @Valid
     private Score score;
@@ -56,4 +57,17 @@ public Extensions getExtensions() {
     public void setExtensions(Extensions extensions) {
         this.extensions = extensions;
     }
+
+    @Override
+    @AssertFalse
+    public boolean isEmpty() {
+        return (
+            score == null &&
+            success == null &&
+            completion == null &&
+            response == null &&
+            duration == null &&
+            extensions == null
+        );
+    }
 }