Prevent scalars from being wrapped

CHANGELOG.md

@@ -10,8 +10,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 ### Changed
+* HalResourecWrapperis#EmbeddedOriginallyAList is now private
 
 ### Fixed
+* Single scalars (e.g. String, Integers, Boolean, etc.) are now not allowed in Wrappers and will result in an exception
 
 ## [1.0.0]
 

README.md

@@ -18,6 +18,15 @@ ___
 
 hateoflux is a lightweight, reactive-first Java library designed to streamline the creation of hypermedia-driven APIs in Spring WebFlux applications. It addresses the limitations of Spring HATEOAS in reactive environments, offering a more intuitive and maintainable approach to building HAL+JSON compliant APIs.
 
+<br>
+<p style="text-align:center">
+<a href="https://github.com/kamillionlabs/hateoflux#getting-started">Getting Started</a> | 
+<a href="https://hateoflux.kamillionlabs.de/docs/cookbook.html">Cookbook</a> | 
+<a href="https://hateoflux.kamillionlabs.de">Documentation</a> | 
+<a href="https://github.com/kamillionlabs/hateoflux-demos">Demos</a>
+</p>
+
+
 ## Table of Contents
 
 - [Why hateoflux?](#why-hateoflux)

src/main/java/de/kamillionlabs/hateoflux/model/hal/HalEmbeddedWrapper.java

@@ -113,6 +113,8 @@ public static <EmbeddedT> HalEmbeddedWrapper<EmbeddedT> wrap(EmbeddedT resourceT
         }
         Assert.isTrue(!(resourceToWrap instanceof Iterable<?>), valueIsNotAllowedToBeOfType("Resource to embed",
                 "collection/iterable"));
+        Assert.isTrue(!isScalar(resourceToWrap.getClass()), valueIsNotAllowedToBeOfType("Embedded",
+                "scalar (e.g. String, int, etc.)"));
         return new HalEmbeddedWrapper<>(resourceToWrap);
     }
 

src/main/java/de/kamillionlabs/hateoflux/model/hal/HalResourceWrapper.java

@@ -23,8 +23,10 @@
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonUnwrapped;
 import de.kamillionlabs.hateoflux.model.link.Link;
+import lombok.AccessLevel;
 import lombok.EqualsAndHashCode;
 import lombok.Getter;
+import lombok.Setter;
 import org.springframework.lang.NonNull;
 import org.springframework.util.Assert;
 
@@ -65,6 +67,8 @@ public final class HalResourceWrapper<ResourceT, EmbeddedT>
     private Map.Entry<String, List<HalEmbeddedWrapper<EmbeddedT>>> embedded;
 
     @JsonIgnore
+    @Getter(AccessLevel.NONE)
+    @Setter(AccessLevel.NONE)
     private Boolean isEmbeddedOriginallyAList;
 
     @JsonProperty("_embedded")
@@ -131,6 +135,8 @@ public static <ResourceT> HalResourceWrapper<ResourceT, Void> wrap(@NonNull Reso
         Assert.isTrue(!(resource instanceof Iterable<?>), valueIsNotAllowedToBeOfType("Resource", "collection" +
                 "/iterable. " +
                 "Use HalListWrapper instead"));
+        Assert.isTrue(!isScalar(resource.getClass()), valueIsNotAllowedToBeOfType("Resource",
+                "scalar (e.g. String, int, etc.)"));
         return new HalResourceWrapper<>(resource);
     }
 

src/main/java/de/kamillionlabs/hateoflux/model/hal/HalWrapper.java

@@ -281,5 +281,13 @@ protected static String determineRelationNameForObject(Object object) {
         }
     }
 
+    protected static boolean isScalar(Class<?> clazz) {
+        return clazz.isPrimitive()
+                || clazz.equals(String.class)
+                || Number.class.isAssignableFrom(clazz)
+                || clazz.equals(Boolean.class)
+                || clazz.equals(Character.class);
+    }
+
 
 }

src/test/java/de/kamillionlabs/hateoflux/model/hal/HalEmbeddedWrapperTest.java

@@ -0,0 +1,45 @@
+package de.kamillionlabs.hateoflux.model.hal;
+
+import org.junit.jupiter.api.Test;
+
+import java.math.BigDecimal;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+
+class HalEmbeddedWrapperTest {
+
+    @Test
+    void givenString_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalEmbeddedWrapper.wrap("hello"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Embedded is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenCharacter_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalEmbeddedWrapper.wrap('h'))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Embedded is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenPrimitiveInt_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalEmbeddedWrapper.wrap(3))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Embedded is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenBigDecimal_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalEmbeddedWrapper.wrap(new BigDecimal("4536433.58")))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Embedded is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenBoolean_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalEmbeddedWrapper.wrap(false))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Embedded is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+}

src/test/java/de/kamillionlabs/hateoflux/model/hal/HalWrapperTest.java

@@ -7,6 +7,7 @@
 import org.assertj.core.api.AssertionsForClassTypes;
 import org.junit.jupiter.api.Test;
 
+import java.math.BigDecimal;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
@@ -79,4 +80,39 @@ void givenEmptyCollection_whenDetermineRelationNameForObject_thenThrowsException
                 .isInstanceOf(IllegalArgumentException.class)
                 .hasMessage("Iterable cannot be empty when determining relation names");
     }
+
+    @Test
+    void givenString_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalResourceWrapper.wrap("hello"))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Resource is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenCharacter_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalResourceWrapper.wrap('h'))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Resource is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenPrimitiveInt_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalResourceWrapper.wrap(3))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Resource is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenBigDecimal_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalResourceWrapper.wrap(new BigDecimal("4536433.58")))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Resource is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
+
+    @Test
+    void givenBoolean_whenWrapping_thenThrowsException() {
+        assertThatThrownBy(() -> HalResourceWrapper.wrap(false))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessage("Resource is not allowed to be of type scalar (e.g. String, int, etc.)");
+    }
 }

src/test/java/de/kamillionlabs/hateoflux/model/hal/serialization/ManualSerializationTest.java

@@ -309,7 +309,6 @@ public void givenHalListWrapperWithEmbeddingListsAndEmptyOnes_whenSerialized_the
         String actualJson = mapper.writeValueAsString(halListWrapper);
 
         // THEN
-        System.out.println(actualJson);
         JSONAssert.assertEquals("""
                 {
                      "_embedded": {