#1457 - Add RepresentationModel.mapLink(LinkRelation, Function<Link, …

…Link>).

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

@@ -21,6 +21,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
@@ -299,6 +300,25 @@ public List<Link> getLinks(LinkRelation relation) {
 		return getLinks(relation.value());
 	}
 
+	/**
+	 * Replaces the link(s) with the given {@link LinkRelation} with the mapper applied to each of the links.
+	 *
+	 * @param relation the {@link LinkRelation} to select the source link(s), must not be {@literal null}.
+	 * @param mapper the {@link Function} to apply to the current link, must not be {@literal null}.
+	 * @return will never be {@literal null}.
+	 * @since 1.3
+	 */
+	public T mapLink(LinkRelation relation, Function<Link, Link> mapper) {
+
+		getLinks(relation).forEach(it -> {
+
+			links.remove(it);
+			links.add(mapper.apply(it));
+		});
+
+		return (T) this;
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see java.lang.Object#toString()

src/test/java/org/springframework/hateoas/RepresentationModelUnitTest.java

@@ -194,4 +194,14 @@ void addsGuardedLinks() {
 		model.addAllIf(false, () -> Links.of(Link.of("not-added", "bar")));
 		assertThat(model.hasLink("bar")).isFalse();
 	}
+
+	@Test // #1457
+	void replacesLink() {
+
+		RepresentationModel<?> model = new RepresentationModel<>();
+		model.add(Link.of("/foo", IanaLinkRelations.SELF));
+		model.mapLink(IanaLinkRelations.SELF, it -> Link.of("/bar"));
+
+		assertThat(model.getRequiredLink(IanaLinkRelations.SELF).getHref()).isEqualTo("/bar");
+	}
 }