#81, #83 - Fixed potential NullPointerExceptions in HalEmbeddedBuilder.

src/main/java/org/springframework/hateoas/hal/HalEmbeddedBuilder.java

@@ -22,6 +22,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.springframework.hateoas.RelProvider;
+import org.springframework.hateoas.Resource;
 import org.springframework.hateoas.core.ObjectUtils;
 
 /**
@@ -29,6 +30,7 @@ import org.springframework.hateoas.core.ObjectUtils;
  * single resource relation to the collection one, once more than one object of the same type is added.
  * 
  * @author Oliver Gierke
+ * @author Dietrich Schulten
  */
 class HalEmbeddedBuilder {
 
@@ -47,13 +49,19 @@ class HalEmbeddedBuilder {
 	}
 
 	/**
-	 * Adds the given value to the embeddeds.
+	 * Adds the given value to the embeddeds. Will skip doing so if the value is {@literal null} or the content of a
+	 * {@link Resource} is {@literal null}.
 	 * 
 	 * @param value
 	 */
 	public void add(Object value) {
 
 		Class<?> type = ObjectUtils.getResourceType(value);
+
+		if (type == null) {
+			return;
+		}
+
 		String singleRel = getDefaultedRelFor(type, false);
 		List<Object> currentValue = embeddeds.get(singleRel);
 

src/test/java/org/springframework/hateoas/hal/HalEmbeddedBuilderUnitTests.java

@@ -24,13 +24,16 @@ import java.util.Map;
 import org.hamcrest.Matchers;
 import org.junit.Before;
 import org.junit.Test;
+import org.springframework.beans.BeanUtils;
 import org.springframework.hateoas.RelProvider;
+import org.springframework.hateoas.Resource;
 import org.springframework.hateoas.core.EvoInflectorRelProvider;
 
 /**
  * Unit tests for {@link HalEmbeddedBuilder}.
  * 
  * @author Oliver Gierke
+ * @author Dietrich Schulten
  */
 public class HalEmbeddedBuilderUnitTests {
 
@@ -60,6 +63,19 @@ public class HalEmbeddedBuilderUnitTests {
 		assertThat(map.get("long"), Matchers.<List<Object>> allOf(hasSize(1), hasItem(1L)));
 	}
 
+	/**
+	 * @see #81, #83
+	 */
+	@Test
+	public void addsNoEmbeddedsForResourceWithoutContent() {
+
+		Resource<?> resource = BeanUtils.instantiateClass(Resource.class);
+		HalEmbeddedBuilder halEmbeddedBuilder = new HalEmbeddedBuilder(provider);
+		halEmbeddedBuilder.add(resource);
+
+		assertThat(halEmbeddedBuilder.asMap().isEmpty(), is(true));
+	}
+
 	private Map<String, List<Object>> setUpBuilder(Object... values) {
 
 		HalEmbeddedBuilder builder = new HalEmbeddedBuilder(provider);