#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();
+}

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

@@ -0,0 +1,44 @@
+/*
+ * 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;
+
+/**
+ * Factory for {@link LinkBuilder} instances.
+ * 
+ * @author Ricardo Gladwell
+ */
+public interface LinkBuilderFactory {
+
+	/**
+	 * Creates a new {@link LinkBuilder} with a base of the mapping annotated to the given target clas (controller,
+	 * service, etc.).
+	 * 
+	 * @param target must not be {@literal null}.
+	 * @return
+	 */
+	LinkBuilder linkTo(Class<?> target);
+
+	/**
+	 * Creates a new {@link LinkBuilder} with a base of the mapping annotated to the given target class (controller,
+	 * service, etc.). The additional parameters are used to fill up potentially available path variables in the class
+	 * scope request mapping.
+	 * 
+	 * @param target must not be {@literal null}.
+	 * @param parameters must not be {@literal null}.
+	 * @return
+	 */
+	LinkBuilder linkTo(Class<?> target, Object... parameters);
+}

src/main/java/org/springframework/hateoas/mvc/ControllerLinkBuilder.java

@@ -20,6 +20,7 @@ import java.net.URI;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.hateoas.Identifiable;
 import org.springframework.hateoas.Link;
+import org.springframework.hateoas.LinkBuilder;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.RequestMapping;
@@ -33,7 +34,7 @@ import org.springframework.web.util.UriTemplate;
  * 
  * @author Oliver Gierke
  */
-public class ControllerLinkBuilder {
+public class ControllerLinkBuilder implements LinkBuilder {
 
 	private final UriComponents uriComponents;
 
@@ -86,11 +87,9 @@ public class ControllerLinkBuilder {
 		return builder.slash(template.expand(parameters));
 	}
 
-	/**
-	 * Adds the given object's {@link String} representation as sub-resource to the current URI.
-	 * 
-	 * @param object
-	 * @return
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#slash(java.lang.Object)
 	 */
 	public ControllerLinkBuilder slash(Object object) {
 
@@ -102,12 +101,9 @@ public class ControllerLinkBuilder {
 		return new ControllerLinkBuilder(UriComponentsBuilder.fromUri(uriComponents.toUri()).pathSegment(segments));
 	}
 
-	/**
-	 * Adds the given {@link AbstractEntity}'s id as sub-resource. Will simply return the current uriComponents if the
-	 * given entity is {@literal null}.
-	 * 
-	 * @param identifyable
-	 * @return
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#slash(org.springframework.hateoas.Identifiable)
 	 */
 	public ControllerLinkBuilder slash(Identifiable<?> identifyable) {
 
@@ -118,30 +114,25 @@ public class ControllerLinkBuilder {
 		return slash(identifyable.getId());
 	}
 
-	/**
-	 * Returns a URI resulting from the uriComponents.
-	 * 
-	 * @return
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#toUri()
 	 */
 	public URI toUri() {
 		return uriComponents.encode().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
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#withRel(java.lang.String)
 	 */
 	public Link withRel(String rel) {
 		return new Link(this.toString(), rel);
 	}
 
-	/**
-	 * Creates the {@link Link} built by the current builder instance with the default self rel.
-	 * 
-	 * @see Link#REL_SELF
-	 * @return
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#withSelfRel()
 	 */
 	public Link withSelfRel() {
 		return new Link(this.toString());

src/main/java/org/springframework/hateoas/mvc/ControllerLinkBuilderFactory.java

@@ -0,0 +1,45 @@
+/*
+ * 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.mvc;
+
+import org.springframework.hateoas.LinkBuilderFactory;
+
+/**
+ * Factory for {@link ControllerLinkBuilder} instances.
+ * 
+ * @author Ricardo Gladwell
+ * @author Oliver Gierke
+ */
+public class ControllerLinkBuilderFactory implements LinkBuilderFactory {
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilderFactory#linkTo(java.lang.Class)
+	 */
+	@Override
+	public ControllerLinkBuilder linkTo(Class<?> controller) {
+		return ControllerLinkBuilder.linkTo(controller);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilderFactory#linkTo(java.lang.Class, java.lang.Object[])
+	 */
+	@Override
+	public ControllerLinkBuilder linkTo(Class<?> controller, Object... parameters) {
+		return ControllerLinkBuilder.linkTo(controller, parameters);
+	}
+}