#566 - Return list of links for a given rel

Introduces `ResourceSupport.getLinks(String rel)` to allow returning ALL links related to a give rel.

Resolves #542,#318,#319,#157

Author: gregturn

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

@@ -1,173 +1,191 @@
-/*
- * Copyright 2012-2015 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.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-
-import javax.xml.bind.annotation.XmlElement;
-
-import org.springframework.util.Assert;
-
-import com.fasterxml.jackson.annotation.JsonIgnore;
-import com.fasterxml.jackson.annotation.JsonProperty;
-
-/**
- * Base class for DTOs to collect links.
- * 
- * @author Oliver Gierke
- */
-public class ResourceSupport implements Identifiable<Link> {
-
-	private final List<Link> links;
-
-	public ResourceSupport() {
-		this.links = new ArrayList<Link>();
-	}
-
-	/**
-	 * Returns the {@link Link} with a rel of {@link Link#REL_SELF}.
-	 */
-	@JsonIgnore
-	public Link getId() {
-		return getLink(Link.REL_SELF);
-	}
-
-	/**
-	 * Adds the given link to the resource.
-	 * 
-	 * @param link
-	 */
-	public void add(Link link) {
-		Assert.notNull(link, "Link must not be null!");
-		this.links.add(link);
-	}
-
-	/**
-	 * Adds all given {@link Link}s to the resource.
-	 * 
-	 * @param links
-	 */
-	public void add(Iterable<Link> links) {
-		Assert.notNull(links, "Given links must not be null!");
-		for (Link candidate : links) {
-			add(candidate);
-		}
-	}
-
-	/**
-	 * Adds all given {@link Link}s to the resource.
-	 *
-	 * @param links must not be {@literal null}.
-	 */
-	public void add(Link... links) {
-		Assert.notNull(links, "Given links must not be null!");
-		add(Arrays.asList(links));
-	}
-
-	/**
-	 * Returns whether the resource contains {@link Link}s at all.
-	 * 
-	 * @return
-	 */
-	public boolean hasLinks() {
-		return !this.links.isEmpty();
-	}
-
-	/**
-	 * Returns whether the resource contains a {@link Link} with the given rel.
-	 * 
-	 * @param rel
-	 * @return
-	 */
-	public boolean hasLink(String rel) {
-		return getLink(rel) != null;
-	}
-
-	/**
-	 * Returns all {@link Link}s contained in this resource.
-	 * 
-	 * @return
-	 */
-	@XmlElement(name = "link", namespace = Link.ATOM_NAMESPACE)
-	@JsonProperty("links")
-	public List<Link> getLinks() {
-		return links;
-	}
-
-	/**
-	 * Removes all {@link Link}s added to the resource so far.
-	 */
-	public void removeLinks() {
-		this.links.clear();
-	}
-
-	/**
-	 * Returns the link with the given rel.
-	 * 
-	 * @param rel
-	 * @return the link with the given rel or {@literal null} if none found.
-	 */
-	public Link getLink(String rel) {
-
-		for (Link link : links) {
-			if (link.getRel().equals(rel)) {
-				return link;
-			}
-		}
-
-		return null;
-	}
-
-	/* 
-	 * (non-Javadoc)
-	 * @see java.lang.Object#toString()
-	 */
-	@Override
-	public String toString() {
-		return String.format("links: %s", links.toString());
-	}
-
-	/* 
-	 * (non-Javadoc)
-	 * @see java.lang.Object#equals(java.lang.Object)
-	 */
-	@Override
-	public boolean equals(Object obj) {
-
-		if (this == obj) {
-			return true;
-		}
-
-		if (obj == null || !obj.getClass().equals(this.getClass())) {
-			return false;
-		}
-
-		ResourceSupport that = (ResourceSupport) obj;
-
-		return this.links.equals(that.links);
-	}
-
-	/* 
-	 * (non-Javadoc)
-	 * @see java.lang.Object#hashCode()
-	 */
-	@Override
-	public int hashCode() {
-		return this.links.hashCode();
-	}
-}
+/*
+ * Copyright 2012-2015 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.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import javax.xml.bind.annotation.XmlElement;
+
+import org.springframework.util.Assert;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+/**
+ * Base class for DTOs to collect links.
+ * 
+ * @author Oliver Gierke
+ */
+public class ResourceSupport implements Identifiable<Link> {
+
+	private final List<Link> links;
+
+	public ResourceSupport() {
+		this.links = new ArrayList<Link>();
+	}
+
+	/**
+	 * Returns the {@link Link} with a rel of {@link Link#REL_SELF}.
+	 */
+	@JsonIgnore
+	public Link getId() {
+		return getLink(Link.REL_SELF);
+	}
+
+	/**
+	 * Adds the given link to the resource.
+	 * 
+	 * @param link
+	 */
+	public void add(Link link) {
+		Assert.notNull(link, "Link must not be null!");
+		this.links.add(link);
+	}
+
+	/**
+	 * Adds all given {@link Link}s to the resource.
+	 * 
+	 * @param links
+	 */
+	public void add(Iterable<Link> links) {
+		Assert.notNull(links, "Given links must not be null!");
+		for (Link candidate : links) {
+			add(candidate);
+		}
+	}
+
+	/**
+	 * Adds all given {@link Link}s to the resource.
+	 *
+	 * @param links must not be {@literal null}.
+	 */
+	public void add(Link... links) {
+		Assert.notNull(links, "Given links must not be null!");
+		add(Arrays.asList(links));
+	}
+
+	/**
+	 * Returns whether the resource contains {@link Link}s at all.
+	 * 
+	 * @return
+	 */
+	public boolean hasLinks() {
+		return !this.links.isEmpty();
+	}
+
+	/**
+	 * Returns whether the resource contains a {@link Link} with the given rel.
+	 * 
+	 * @param rel
+	 * @return
+	 */
+	public boolean hasLink(String rel) {
+		return getLink(rel) != null;
+	}
+
+	/**
+	 * Returns all {@link Link}s contained in this resource.
+	 * 
+	 * @return
+	 */
+	@XmlElement(name = "link", namespace = Link.ATOM_NAMESPACE)
+	@JsonProperty("links")
+	public List<Link> getLinks() {
+		return links;
+	}
+
+	/**
+	 * Removes all {@link Link}s added to the resource so far.
+	 */
+	public void removeLinks() {
+		this.links.clear();
+	}
+
+	/**
+	 * Returns the link with the given rel.
+	 * 
+	 * @param rel
+	 * @return the link with the given rel or {@literal null} if none found.
+	 */
+	public Link getLink(String rel) {
+
+		for (Link link : links) {
+			if (link.getRel().equals(rel)) {
+				return link;
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * Returns all {@link Link}s with the given relation type.
+	 *
+	 * @return the links in a {@link List}
+	 */
+	public List<Link> getLinks(String rel) {
+
+		List<Link> relatedLinks = new ArrayList<Link>();
+		
+		for (Link link : links) {
+			if (link.getRel().equals(rel)) {
+				relatedLinks.add(link);
+			}
+		}
+		
+		return relatedLinks;
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return String.format("links: %s", links.toString());
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+
+		if (this == obj) {
+			return true;
+		}
+
+		if (obj == null || !obj.getClass().equals(this.getClass())) {
+			return false;
+		}
+
+		ResourceSupport that = (ResourceSupport) obj;
+
+		return this.links.equals(that.links);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		return this.links.hashCode();
+	}
+}