Initial commit.

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

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+/*
+ * 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.core.annotation.AnnotationUtils;
+import org.springframework.hateoas.Identifiable;
+import org.springframework.hateoas.Link;
+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;
+
+/**
+ * Builder to ease building {@link Link} instances pointing to Spring MVC controllers.
+ * 
+ * @author Oliver Gierke
+ */
+public class ControllerLinkBuilder {
+
+	private final UriComponents builder;
+
+	/**
+	 * Creates a new {@link ControllerLinkBuilder}.
+	 * 
+	 * @param builder must not be {@literal null}.
+	 */
+	private ControllerLinkBuilder(UriComponentsBuilder builder) {
+		Assert.notNull(builder);
+		this.builder = builder.build();
+	}
+
+	/**
+	 * Creates a new {@link ControllerLinkBuilder} with a base of the mapping annotated to the given controller class.
+	 * 
+	 * @param controller
+	 * @return
+	 */
+	public static ControllerLinkBuilder linkTo(Class<?> controller) {
+		return linkTo(controller, new Object[0]);
+	}
+
+	public static ControllerLinkBuilder linkTo(Class<?> controller, Object... parameters) {
+
+		RequestMapping annotation = controller.getAnnotation(RequestMapping.class);
+		String[] mapping = annotation == null ? new String[0] : (String[]) AnnotationUtils.getValue(annotation);
+
+		if (mapping.length > 1) {
+			throw new IllegalStateException("Multiple controller mappings defined! Unable to build URI!");
+		}
+
+		ControllerLinkBuilder builder = new ControllerLinkBuilder(ServletUriComponentsBuilder.fromCurrentServletMapping());
+
+		if (mapping.length == 0) {
+			return builder;
+		}
+
+		UriTemplate template = new UriTemplate(mapping[0]);
+		return builder.slash(template.expand(parameters));
+	}
+
+	/**
+	 * Adds the given object's {@link String} representation as sub-resource to the current URI.
+	 * 
+	 * @param object
+	 * @return
+	 */
+	public ControllerLinkBuilder slash(Object object) {
+
+		if (object == null) {
+			return this;
+		}
+
+		String[] segments = StringUtils.tokenizeToStringArray(object.toString(), "/");
+		return new ControllerLinkBuilder(UriComponentsBuilder.fromUri(builder.toUri()).pathSegment(segments));
+	}
+
+	/**
+	 * Adds the given {@link AbstractEntity}'s id as sub-resource. Will simply return the current builder if the given
+	 * entity is {@literal null}.
+	 * 
+	 * @param identifyable
+	 * @return
+	 */
+	public ControllerLinkBuilder slash(Identifiable<?> identifyable) {
+
+		if (identifyable == null) {
+			return this;
+		}
+
+		return slash(identifyable.getId());
+	}
+
+	/**
+	 * Returns a URI resulting from the builder.
+	 * 
+	 * @return
+	 */
+	public URI toUri() {
+		return builder.encode().toUri();
+	}
+
+	public Link withRel(String rel) {
+		return new Link(this.toString(), rel);
+	}
+
+	public Link withSelfRel() {
+		return new Link(this.toString());
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return toUri().normalize().toASCIIString();
+	}
+}

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

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+/*
+ * 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 coimport javax.xml.bind.annotation.XmlNs;
+import javax.xml.bind.annotation.XmlSchema;
+
+
+eed 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 static org.springframework.hateoas.mvc.ControllerLinkBuilder.*;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.springframework.beans.BeanUtils;
+import org.springframework.hateoas.Identifiable;
+import org.springframework.hateoas.ResourceAssembler;
+import org.springframework.hateoas.ResourceSupport;
+import org.springframework.util.Assert;
+
+/**
+ * Base class to implement {@link ResourceAssembler}s. Will automate {@link ResourceSupport} instance creation and make
+ * sure a self-link is always added.
+ * 
+ * @author Oliver Gierke
+ */
+public abstract class ResourceAssemblerSupport<T extends Identifiable<?>, D extends ResourceSupport> implements
+		ResourceAssembler<T, D> {
+
+	public static class EntityId {
+
+		private final Object id;
+
+		public EntityId(Object id) {
+			Assert.notNull(id);
+			this.id = id;
+		}
+
+		public static EntityId id(Object object) {
+			return new EntityId(object);
+		}
+
+		@Override
+		public String toString() {
+			return this.id.toString();
+		}
+	}
+
+	private final Class<?> controllerClass;
+	private final Class<D> resourceType;
+
+	/**
+	 * Creates a new {@link ResourceAssemblerSupport} using the given controller class and resource type.
+	 * 
+	 * @param controllerClass must not be {@literal null}.
+	 * @param resourceType must not be {@literal null}.
+	 */
+	public ResourceAssemblerSupport(Class<?> controllerClass, Class<D> resourceType) {
+
+		Assert.notNull(controllerClass);
+		Assert.notNull(resourceType);
+
+		this.controllerClass = controllerClass;
+		this.resourceType = resourceType;
+	}
+
+	/**
+	 * Converts all given entities into resources.
+	 * 
+	 * @see #toResource(Object)
+	 * @param entities
+	 * @return
+	 */
+	public List<D> toResources(Iterable<? extends T> entities) {
+
+		List<D> result = new ArrayList<D>();
+
+		for (T entity : entities) {
+			result.add(toResource(entity));
+		}
+
+		return result;
+	}
+
+	/**
+	 * Creates a new resource and adds a self link to it consisting using the {@link Identifiable}'s id.
+	 * 
+	 * @param entity must not be {@literal null}.
+	 * @return
+	 */
+	protected D createResource(T entity) {
+		return createResource(entity, new Object[0]);
+	}
+
+	protected D createResource(T entity, Object... parameters) {
+		return createResource(entity, EntityId.id(entity.getId()), parameters);
+	}
+
+	/**
+	 * Creates a new resource with a self link to the given id.
+	 * 
+	 * @param entity
+	 * @param id
+	 * @return
+	 */
+	protected D createResource(T entity, EntityId id) {
+		return createResource(entity, id, new Object[0]);
+	}
+
+	protected D createResource(T entity, EntityId id, Object... parameters) {
+
+		Assert.notNull(entity);
+		Assert.notNull(id);
+
+		D instance = instantiateResource(entity);
+		instance.add(linkTo(controllerClass, unwrapIdentifyables(parameters)).slash(id).withSelfRel());
+		return instance;
+	}
+
+	/**
+	 * Extracts the ids of the given values in case they're {@link Identifiable}s. Returns all other objects as they are.
+	 * 
+	 * @param values must not be {@literal null}.
+	 * @return
+	 */
+	private Object[] unwrapIdentifyables(Object[] values) {
+
+		List<Object> result = new ArrayList<Object>(values.length);
+
+		for (Object element : Arrays.asList(values)) {
+			result.add((element instanceof Identifiable) ? ((Identifiable<?>) element).getId() : element);
+		}
+
+		return result.toArray();
+	}
+
+	/**
+	 * Instantiates the resource object. Default implementation will assume a no-arg constructor and use reflection but
+	 * can be overridden to manually set up the object instance initially (e.g. to improve performance if this becomes an
+	 * issue).
+	 * 
+	 * @param entity
+	 * @return
+	 */
+	protected D instantiateResource(T entity) {
+		return BeanUtils.instantiateClass(resourceType);
+	}
+}

src/main/java/org/springframework/hateoas/mvc/package-info.java

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+/**
+ * Spring MVC helper classes to build {@link org.springframework.hateoas.Link}s and assemble 
+ * {@link org.springframework.hateoas.ResourceSupport} types.
+ */
+package org.springframework.hateoas.mvc;
+