#340 - Polishing.

Moved AffordanceModelFactory into core package as it's SPI. Switched to Spring Factories lookup of implementation classes so that we avoid a package dependency between the MVC package and the media type specific packages. Removed reference to MediaType from AffordanceModelFactory to AffordanceModel so that a factory can even provide models for different MediaTypes (i.e. different flavors of the same one, e.g. HAL Forms for JSON and XML). Also removed addAffordanceModel(…) from Affordance to not force the implementations into mutability. Made most of the affordance building API types package protected. HalFormsAffordanceModel now uses MethodParameters abstraction to simplify model parsing code.

Tweaked HAL forms model to work with factory methods for required properties and wither methods to add optional properties. Tweaked and inlined mixin types in Jackson module for HAL forms.

Slight API polishing on Link to make sure Affordance collecting methods are not named with….

Tweaked Lombok setup to use all caps for logger constants. Removed deprecation warnings in Jackson2HalModule.

src/main/java/org/springframework/hateoas/Link.java

@@ -34,12 +34,12 @@ import javax.xml.bind.annotation.XmlAttribute;
 import javax.xml.bind.annotation.XmlTransient;
 import javax.xml.bind.annotation.XmlType;
 
-import org.springframework.hateoas.core.LinkBuilderSupport;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonInclude;
 
 /**
  * Value object for links.
@@ -48,6 +48,7 @@ import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
  * @author Greg Turnquist
  */
 @XmlType(name = "link", namespace = Link.ATOM_NAMESPACE)
+@JsonInclude(JsonInclude.Include.NON_NULL)
 @JsonIgnoreProperties("templated")
 @AllArgsConstructor(access = AccessLevel.PACKAGE)
 @Getter
@@ -113,11 +114,11 @@ public class Link implements Serializable {
 	}
 
 	public Link(String href, String rel, List<Affordance> affordances) {
-		
+
 		this(href, rel);
 
 		Assert.notNull(affordances, "affordances must not be null!");
-		
+
 		this.affordances = affordances;
 	}
 
@@ -134,7 +135,7 @@ public class Link implements Serializable {
 	 * @return
 	 */
 	public List<Affordance> getAffordances() {
-		return new ArrayList<Affordance>(Collections.unmodifiableCollection(this.affordances));
+		return Collections.unmodifiableList(this.affordances);
 	}
 
 	/**
@@ -149,35 +150,46 @@ public class Link implements Serializable {
 	/**
 	 * Create new {@link Link} with an additional {@link Affordance}.
 	 *
-	 * @param affordance
+	 * @param affordance must not be {@literal null}.
 	 * @return
 	 */
-	public Link withAffordance(Affordance affordance) {
+	public Link andAffordance(Affordance affordance) {
+
+		Assert.notNull(affordance, "Affordance must not be null!");
 
 		List<Affordance> newAffordances = new ArrayList<Affordance>();
 		newAffordances.addAll(this.affordances);
 		newAffordances.add(affordance);
 
-		return new Link(this.rel, this.href, this.hreflang ,this.media, this.title, this.type,
-			this.deprecation, this.template, newAffordances);
+		return withAffordances(newAffordances);
 	}
 
 	/**
 	 * Create new {@link Link} with additional {@link Affordance}s.
 	 * 
-	 * @param affordances
+	 * @param affordances must not be {@literal null}.
 	 * @return
 	 */
-	public Link addAffordances(List<Affordance> affordances) {
+	public Link andAffordances(List<Affordance> affordances) {
 
 		List<Affordance> newAffordances = new ArrayList<Affordance>();
 		newAffordances.addAll(this.affordances);
 		newAffordances.addAll(affordances);
 
-		return new Link(this.rel, this.href, this.hreflang ,this.media, this.title, this.type,
-			this.deprecation, this.template, newAffordances);
+		return withAffordances(newAffordances);
 	}
 
+	/**
+	 * Creats a new {@link Link} with the given {@link Affordance}s.
+	 * 
+	 * @param affordances must not be {@literal null}.
+	 * @return
+	 */
+	public Link withAffordances(List<Affordance> affordances) {
+
+		return new Link(this.rel, this.href, this.hreflang, this.media, this.title, this.type, this.deprecation,
+				this.template, affordances);
+	}
 
 	/**
 	 * Returns the variable names contained in the template.