#12 - Introduced interfaces for LinkBuilder(Factory) to improve testability.

LinkBuilder and LinkBuilderFactory interface extracted from ControllerLinkBuilder for easier mocking and so that alternative implementations (such as for CXF) can be created.

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

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2012 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.hateoas;
+
+import java.net.URI;
+
+/**
+ * Builder to ease building {@link Link} instances.
+ * 
+ * @author Ricardo Gladwell
+ */
+public interface LinkBuilder {
+
+	/**
+	 * Adds the given object's {@link String} representation as sub-resource to the current URI.
+	 * 
+	 * @param object
+	 * @return
+	 */
+	LinkBuilder slash(Object object);
+
+	/**
+	 * Adds the given {@link Identifiable}'s id as sub-resource. Will simply return the {@link LinkBuilder} as is if the
+	 * given entity is {@literal null}.
+	 * 
+	 * @param identifiable
+	 * @return
+	 */
+	LinkBuilder slash(Identifiable<?> identifiable);
+
+	/**
+	 * Creates a URI of the link built by the current builder instance.
+	 * 
+	 * @return
+	 */
+	URI toUri();
+
+	/**
+	 * Creates the {@link Link} built by the current builder instance with the given rel.
+	 * 
+	 * @param rel must not be {@literal null} or empty.
+	 * @return
+	 */
+	Link withRel(String rel);
+
+	/**
+	 * Creates the {@link Link} built by the current builder instance with the default self rel.
+	 * 
+	 * @see Link#REL_SELF
+	 * @return
+	 */
+	Link withSelfRel();
+}