DATAREST-39: Modified the DELETEing of links so that an attempt to delete a required relationship will result in a 405 Method Not Allowed. Had to change the entities and tests to accommodate the new required relationship on the Address entity, which pingponged into a number of changes.

spring-data-rest-repository/src/main/java/org/springframework/data/rest/repository/AttributeMetadata.java

@@ -1,5 +1,6 @@
 package org.springframework.data.rest.repository;
 
+import java.lang.annotation.Annotation;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
@@ -90,6 +91,27 @@ public interface AttributeMetadata {
    */
   Map asMap(Object target);
 
+  /**
+   * Does this attribute have the given annotation on it?
+   *
+   * @param annoType
+   *     The type of annotation to search for.
+   *
+   * @return {@literal true} if this annotation exists on this attribute, {@literal false} otherwise.
+   */
+  boolean hasAnnotation(Class<? extends Annotation> annoType);
+
+  /**
+   * Get the given annotation.
+   *
+   * @param annoType
+   *     The type of annotation to get.
+   * @param <A>
+   *
+   * @return The annotation, or {@literal null} if it doesn't exist.
+   */
+  <A extends Annotation> A annotation(Class<A> annoType);
+
   /**
    * Get the path of this attribute.
    *

spring-data-rest-repository/src/main/java/org/springframework/data/rest/repository/jpa/JpaAttributeMetadata.java

@@ -1,6 +1,7 @@
 package org.springframework.data.rest.repository.jpa;
 
 import java.beans.PropertyDescriptor;
+import java.lang.annotation.Annotation;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.Collection;
@@ -126,6 +127,14 @@ public class JpaAttributeMetadata implements AttributeMetadata {
     return (Map)get(target);
   }
 
+  @Override public boolean hasAnnotation(Class<? extends Annotation> annoType) {
+    return field.isAnnotationPresent(annoType);
+  }
+
+  @Override public <A extends Annotation> A annotation(Class<A> annoType) {
+    return field.getAnnotation(annoType);
+  }
+
   @Override public Object get(Object target) {
     try {
       if(null != getter) {