559: fix multiple encodings of params

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

@@ -22,6 +22,7 @@
 import lombok.experimental.Wither;
 
 import java.io.Serializable;
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -49,7 +50,7 @@
  */
 @XmlType(name = "link", namespace = Link.ATOM_NAMESPACE)
 @JsonInclude(JsonInclude.Include.NON_NULL)
-@JsonIgnoreProperties(value = "templated", ignoreUnknown = true)
+@JsonIgnoreProperties(value = "templated", ignoreUnknown = true)
 @AllArgsConstructor(access = AccessLevel.PACKAGE)
 @Getter
 @EqualsAndHashCode(of = { "rel", "href", "hreflang", "media", "title", "deprecation", "affordances" })
@@ -131,7 +132,7 @@ protected Link() {
 
 	/**
 	 * Returns safe copy of {@link Affordance}s.
-	 * 
+	 *
 	 * @return
 	 */
 	public List<Affordance> getAffordances() {
@@ -166,7 +167,7 @@ public Link andAffordance(Affordance affordance) {
 
 	/**
 	 * Create new {@link Link} with additional {@link Affordance}s.
-	 * 
+	 *
 	 * @param affordances must not be {@literal null}.
 	 * @return
 	 */
@@ -181,7 +182,7 @@ public Link andAffordances(List<Affordance> affordances) {
 
 	/**
 	 * Creats a new {@link Link} with the given {@link Affordance}s.
-	 * 
+	 *
 	 * @param affordances must not be {@literal null}.
 	 * @return
 	 */
@@ -227,7 +228,12 @@ public boolean isTemplated() {
 	 * @return
 	 */
 	public Link expand(Object... arguments) {
-		return new Link(getUriTemplate().expand(arguments).toString(), getRel());
+
+		URI uri = (arguments == null || arguments.length == 0) ?
+				getUriTemplate().checkParams(arguments) :
+				getUriTemplate().expand(arguments);
+
+		return new Link(uri.toString(), getRel());
 	}
 
 	/**
@@ -242,7 +248,7 @@ public Link expand(Map<String, ? extends Object> arguments) {
 
 	/**
 	 * Returns whether the current {@link Link} has the given link relation.
-	 * 
+	 *
 	 * @param rel must not be {@literal null} or empty.
 	 * @return
 	 */

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

@@ -203,6 +203,28 @@ public URI expand(Object... parameters) {
 		return builder.build().toUri();
 	}
 
+	/**
+	 * Expands the {@link UriTemplate} using the given parameters. The values will be applied in the order of the
+	 * variables discovered.
+	 *
+	 * @param parameters
+	 * @return
+	 * @see #expand(Map)
+	 */
+	public URI checkParams(Object... parameters) {
+		org.springframework.web.util.UriTemplate baseTemplate = new org.springframework.web.util.UriTemplate(baseUri);
+		UriComponentsBuilder builder = UriComponentsBuilder.fromUri(baseTemplate.expand(parameters));
+		Iterator<Object> iterator = Arrays.asList(parameters).iterator();
+
+		for (TemplateVariable variable : getOptionalVariables()) {
+
+			Object value = iterator.hasNext() ? iterator.next() : null;
+			appendToBuilder(builder, variable, value);
+		}
+
+		return URI.create(baseUri);
+	}
+
 	/**
 	 * Expands the {@link UriTemplate} using the given parameters.
 	 * 

src/test/java/org/springframework/hateoas/mvc/ControllerLinkBuilderUnitTest.java

@@ -384,6 +384,27 @@ public void linksToMethodWithPathVariableContainingBlank() {
 		assertThat(link.getHref()).endsWith("/something/with%20blank/foo");
 	}
 
+	@Test
+	public void uriComponentsToMethodWithPathVariableContainingBlankAnsOptionalQueryParams() {
+
+		Link link = linkTo(methodOn(ControllerWithMethods.class).methodForNextPage("with blank", 0, 10)).withSelfRel();
+
+		UriComponents components = toComponents(link);
+		assertThat(components.toUriString(), containsString("/something/with%20blank/foo"));
+		assertThat(components.toUriString(), containsString("offset=0"));
+		assertThat(components.toUriString(), containsString("limit=10"));
+	}
+
+	@Test
+	public void uriComponentsToMethodWithPathVariableContainingBlankAnsOptionalQueryParamNull() {
+
+		Link link = linkTo(methodOn(ControllerWithMethods.class).methodForNextPage("with blank", null, 10)).withSelfRel();
+
+		UriComponents components = toComponents(link);
+		assertThat(components.toUriString(), containsString("/something/with%20blank/foo"));
+		assertThat(components.toUriString(), containsString("limit=10"));
+	}
+
 	/**
 	 * @see #192
 	 */
@@ -590,6 +611,18 @@ public void alternativePathVariableParameter() {
 		assertThat(link.getHref()).isEqualTo("http://localhost/something/bar/foo");
 	}
 
+	@Test
+	public void uriComponentsToMethodWithPathVariableAndRequestParamsContainingNull()
+	{
+		Link link = linkTo(methodOn(ControllerWithMethods.class).methodForNextPage("1", null, 10)).withSelfRel();
+
+		UriComponents components = toComponents(link);
+		assertThat(components.getPath(), is(equalTo("/something/1/foo")));
+
+		MultiValueMap<String, String> queryParams = components.getQueryParams();
+		assertThat(queryParams.get("limit"), contains("10"));
+	}
+
 	private static UriComponents toComponents(Link link) {
 		return UriComponentsBuilder.fromUriString(link.expand().getHref()).build();
 	}