#13 - Introduced LinkBuilder implementation inspecting JAX-RS @Path annotation.

Refactored LinkBuilder(Factory) classes to extract reusable code into common superclass for ControllerLinkBuilder and JaxRsLinkBuilder.

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

@@ -20,7 +20,7 @@ package org.springframework.hateoas;
  * 
  * @author Ricardo Gladwell
  */
-public interface LinkBuilderFactory {
+public interface LinkBuilderFactory<T extends LinkBuilder> {
 
 	/**
 	 * Creates a new {@link LinkBuilder} with a base of the mapping annotated to the given target clas (controller,
@@ -29,7 +29,7 @@ public interface LinkBuilderFactory {
 	 * @param target must not be {@literal null}.
 	 * @return
 	 */
-	LinkBuilder linkTo(Class<?> target);
+	T linkTo(Class<?> target);
 
 	/**
 	 * Creates a new {@link LinkBuilder} with a base of the mapping annotated to the given target class (controller,
@@ -40,5 +40,5 @@ public interface LinkBuilderFactory {
 	 * @param parameters must not be {@literal null}.
 	 * @return
 	 */
-	LinkBuilder linkTo(Class<?> target, Object... parameters);
+	T linkTo(Class<?> target, Object... parameters);
 }

src/main/java/org/springframework/hateoas/jaxrs/JaxRsLinkBuilder.java

@@ -0,0 +1,90 @@
+/*
+ * 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.jaxrs;
+
+import javax.ws.rs.Path;
+
+import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.hateoas.LinkBuilder;
+import org.springframework.hateoas.mvc.UriComponentsLinkBuilder;
+import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
+import org.springframework.web.util.UriComponentsBuilder;
+import org.springframework.web.util.UriTemplate;
+
+/**
+ * {@link LinkBuilder} to derive URI mappings from a JAX-RS {@link Path} annotation.
+ * 
+ * @author Oliver Gierke
+ */
+public class JaxRsLinkBuilder extends UriComponentsLinkBuilder<JaxRsLinkBuilder> {
+
+	/**
+	 * Creates a new {@link JaxRsLinkBuilder} from the given {@link UriComponentsBuilder}.
+	 * 
+	 * @param builder must not be {@literal null}.
+	 */
+	private JaxRsLinkBuilder(UriComponentsBuilder builder) {
+		super(builder);
+	}
+
+	/**
+	 * Creates a {@link JaxRsLinkBuilder} instance to link to the {@link Path} mapping tied to the given class.
+	 * 
+	 * @param service the class to discover the annotation on, must not be {@literal null}.
+	 * @return
+	 */
+	public static JaxRsLinkBuilder linkTo(Class<?> service) {
+		return linkTo(service, new Object[0]);
+	}
+
+	/**
+	 * Creates a new {@link JaxRsLinkBuilder} instance to link to the {@link Path} mapping tied to the given class binding
+	 * the given parameters to the URI template.
+	 * 
+	 * @param service the class to discover the annotation on, must not be {@literal null}.
+	 * @param parameters additional parameters to bind to the URI template declared in the annotation, must not be
+	 *          {@literal null}.
+	 * @return
+	 */
+	public static JaxRsLinkBuilder linkTo(Class<?> service, Object... parameters) {
+
+		Path annotation = AnnotationUtils.findAnnotation(service, Path.class);
+		String path = (String) AnnotationUtils.getValue(annotation);
+
+		JaxRsLinkBuilder builder = new JaxRsLinkBuilder(ServletUriComponentsBuilder.fromCurrentServletMapping());
+
+		UriTemplate template = new UriTemplate(path);
+		return builder.slash(template.expand(parameters));
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.UriComponentsLinkBuilder#getThis()
+	 */
+	@Override
+	protected JaxRsLinkBuilder getThis() {
+		return this;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.UriComponentsLinkBuilder#createNewInstance(org.springframework.web.util.UriComponentsBuilder)
+	 */
+	@Override
+	protected JaxRsLinkBuilder createNewInstance(UriComponentsBuilder builder) {
+		return new JaxRsLinkBuilder(builder);
+	}
+}

src/main/java/org/springframework/hateoas/jaxrs/JaxRsLinkBuilderFactory.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.jaxrs;
+
+import org.springframework.hateoas.LinkBuilder;
+import org.springframework.hateoas.LinkBuilderFactory;
+
+/**
+ * Factory for {@link LinkBuilder} instances based on the path mapping annotated on the given JAX-RS service.
+ * 
+ * @author Ricardo Gladwell
+ * @author Oliver Gierke
+ */
+public class JaxRsLinkBuilderFactory implements LinkBuilderFactory<JaxRsLinkBuilder> {
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilderFactory#linkTo(java.lang.Class)
+	 */
+	public JaxRsLinkBuilder linkTo(Class<?> service) {
+		return JaxRsLinkBuilder.linkTo(service);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilderFactory#linkTo(java.lang.Class, java.lang.Object[])
+	 */
+	@Override
+	public JaxRsLinkBuilder linkTo(Class<?> service, Object... parameters) {
+		return JaxRsLinkBuilder.linkTo(service, parameters);
+	}
+}

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

@@ -15,17 +15,11 @@
  */
 package org.springframework.hateoas.mvc;
 
-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;
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
-import org.springframework.web.util.UriComponents;
 import org.springframework.web.util.UriComponentsBuilder;
 import org.springframework.web.util.UriTemplate;
 
@@ -34,24 +28,21 @@ import org.springframework.web.util.UriTemplate;
  * 
  * @author Oliver Gierke
  */
-public class ControllerLinkBuilder implements LinkBuilder {
-
-	private final UriComponents uriComponents;
+public class ControllerLinkBuilder extends UriComponentsLinkBuilder<ControllerLinkBuilder> {
 
 	/**
-	 * Creates a new {@link ControllerLinkBuilder}.
+	 * Creates a new {@link ControllerLinkBuilder} using the given {@link UriComponentsBuilder}.
 	 * 
-	 * @param uriComponents must not be {@literal null}.
+	 * @param builder must not be {@literal null}.
 	 */
 	private ControllerLinkBuilder(UriComponentsBuilder builder) {
-		Assert.notNull(builder);
-		this.uriComponents = builder.build();
+		super(builder);
 	}
 
 	/**
 	 * Creates a new {@link ControllerLinkBuilder} with a base of the mapping annotated to the given controller class.
 	 * 
-	 * @param controller must not be {@literal null}.
+	 * @param controller the class to discover the annotation on, must not be {@literal null}.
 	 * @return
 	 */
 	public static ControllerLinkBuilder linkTo(Class<?> controller) {
@@ -62,8 +53,9 @@ public class ControllerLinkBuilder implements LinkBuilder {
 	 * Creates a new {@link ControllerLinkBuilder} with a base of the mapping annotated to the given controller class. The
 	 * additional parameters are used to fill up potentially available path variables in the class scop request mapping.
 	 * 
-	 * @param controller must not be {@literal null}.
-	 * @param parameters
+	 * @param controller the class to discover the annotation on, must not be {@literal null}.
+	 * @param parameters additional parameters to bind to the URI template declared in the annotation, must not be
+	 *          {@literal null}.
 	 * @return
 	 */
 	public static ControllerLinkBuilder linkTo(Class<?> controller, Object... parameters) {
@@ -87,63 +79,21 @@ public class ControllerLinkBuilder implements LinkBuilder {
 		return builder.slash(template.expand(parameters));
 	}
 
-	/*
+	/* 
 	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.LinkBuilder#slash(java.lang.Object)
-	 */
-	public ControllerLinkBuilder slash(Object object) {
-
-		if (object == null) {
-			return this;
-		}
-
-		String[] segments = StringUtils.tokenizeToStringArray(object.toString(), "/");
-		return new ControllerLinkBuilder(UriComponentsBuilder.fromUri(uriComponents.toUri()).pathSegment(segments));
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.LinkBuilder#slash(org.springframework.hateoas.Identifiable)
-	 */
-	public ControllerLinkBuilder slash(Identifiable<?> identifyable) {
-
-		if (identifyable == null) {
-			return this;
-		}
-
-		return slash(identifyable.getId());
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.LinkBuilder#toUri()
-	 */
-	public URI toUri() {
-		return uriComponents.encode().toUri();
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.LinkBuilder#withRel(java.lang.String)
-	 */
-	public Link withRel(String rel) {
-		return new Link(this.toString(), rel);
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.LinkBuilder#withSelfRel()
-	 */
-	public Link withSelfRel() {
-		return new Link(this.toString());
-	}
-
-	/*
-	 * (non-Javadoc)
-	 * @see java.lang.Object#toString()
+	 * @see org.springframework.hateoas.UriComponentsLinkBuilder#getThis()
 	 */
 	@Override
-	public String toString() {
-		return toUri().normalize().toASCIIString();
+	protected ControllerLinkBuilder getThis() {
+		return this;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.UriComponentsLinkBuilder#createNewInstance(org.springframework.web.util.UriComponentsBuilder)
+	 */
+	@Override
+	protected ControllerLinkBuilder createNewInstance(UriComponentsBuilder builder) {
+		return new ControllerLinkBuilder(builder);
 	}
 }

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

@@ -18,12 +18,13 @@ package org.springframework.hateoas.mvc;
 import org.springframework.hateoas.LinkBuilderFactory;
 
 /**
- * Factory for {@link ControllerLinkBuilder} instances.
+ * Factory for {@link UriComponentsLinkBuilder} instances based on the request mapping annotated on the given
+ * controller.
  * 
  * @author Ricardo Gladwell
  * @author Oliver Gierke
  */
-public class ControllerLinkBuilderFactory implements LinkBuilderFactory {
+public class ControllerLinkBuilderFactory implements LinkBuilderFactory<ControllerLinkBuilder> {
 
 	/*
 	 * (non-Javadoc)

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

@@ -0,0 +1,123 @@
+/*
+ * 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 java.net.URI;
+
+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.util.UriComponents;
+import org.springframework.web.util.UriComponentsBuilder;
+
+/**
+ * Base class to implement {@link LinkBuilder}s based on a Spring MVC {@link UriComponentsBuilder}.
+ * 
+ * @author Ricardo Gladwell
+ * @author Oliver Gierke
+ */
+public abstract class UriComponentsLinkBuilder<T extends LinkBuilder> implements LinkBuilder {
+
+	private final UriComponents uriComponents;
+
+	/**
+	 * Creates a new {@link UriComponentsLinkBuilder} using the given {@link UriComponentsBuilder}.
+	 * 
+	 * @param builder must not be {@literal null}.
+	 */
+	public UriComponentsLinkBuilder(UriComponentsBuilder builder) {
+
+		Assert.notNull(builder);
+		this.uriComponents = builder.build();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#slash(java.lang.Object)
+	 */
+	public T slash(Object object) {
+
+		if (object == null) {
+			return getThis();
+		}
+
+		String[] segments = StringUtils.tokenizeToStringArray(object.toString(), "/");
+		return createNewInstance(UriComponentsBuilder.fromUri(uriComponents.toUri()).pathSegment(segments));
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#slash(org.springframework.hateoas.Identifiable)
+	 */
+	public LinkBuilder slash(Identifiable<?> identifyable) {
+
+		if (identifyable == null) {
+			return this;
+		}
+
+		return slash(identifyable.getId());
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#toUri()
+	 */
+	public URI toUri() {
+		return uriComponents.encode().toUri();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#withRel(java.lang.String)
+	 */
+	public Link withRel(String rel) {
+		return new Link(this.toString(), rel);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.hateoas.LinkBuilder#withSelfRel()
+	 */
+	public Link withSelfRel() {
+		return new Link(this.toString());
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return toUri().normalize().toASCIIString();
+	}
+
+	/**
+	 * Returns the current concrete instance.
+	 * 
+	 * @return
+	 */
+	protected abstract T getThis();
+
+	/**
+	 * Creates a new instance of the sub-class.
+	 * 
+	 * @param builder will never be {@literal null}.
+	 * @return
+	 */
+	protected abstract T createNewInstance(UriComponentsBuilder builder);
+}