From a16375bb1778ed7e63c5205168aeee3563d0c96d Mon Sep 17 00:00:00 2001
From: Oliver Gierke <ogierke@gopivotal.com>
Date: Thu, 23 Jan 2014 15:41:37 +0100
Subject: [PATCH] DATACMNS-418 - PagedResourcesAssembler now exposes method to
 append template parameters.

PagedResourcesAssembler.appendPaginationParameterTemplates adds the currently missing pagination template variables to the given link.
---
 .../data/web/PagedResourcesAssembler.java     | 23 ++++++++++++--
 .../web/PagedResourcesAssemblerUnitTests.java | 30 +++++++++++++++++++
 2 files changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/main/java/org/springframework/data/web/PagedResourcesAssembler.java b/src/main/java/org/springframework/data/web/PagedResourcesAssembler.java
index 3eeb40215..cf7f3ba18 100644
--- a/src/main/java/org/springframework/data/web/PagedResourcesAssembler.java
+++ b/src/main/java/org/springframework/data/web/PagedResourcesAssembler.java
@@ -113,6 +113,25 @@ public class PagedResourcesAssembler<T> implements ResourceAssembler<Page<T>, Pa
 		return createResource(page, assembler, link);
 	}
 
+	/**
+	 * Adds the pagination parameters for all parameters not already present in the given {@link Link}.
+	 * 
+	 * @param link must not be {@literal null}.
+	 * @return
+	 */
+	public Link appendPaginationParameterTemplates(Link link) {
+
+		Assert.notNull(link, "Link must not be null!");
+
+		String uri = link.getHref();
+		UriTemplate uriTemplate = new UriTemplate(uri);
+		UriComponents uriComponents = UriComponentsBuilder.fromUriString(uri).build();
+
+		TemplateVariables variables = pageableResolver.getPaginationTemplateVariables(getMethodParameter(), uriComponents);
+
+		return new Link(uriTemplate.with(variables), link.getRel());
+	}
+
 	private <S, R extends ResourceSupport> PagedResources<R> createResource(Page<S> page,
 			ResourceAssembler<S, R> assembler, Link link) {
 
@@ -144,9 +163,7 @@ public class PagedResourcesAssembler<T> implements ResourceAssembler<Page<T>, Pa
 			foo(resources, page.previousPageable(), uri, Link.REL_PREVIOUS);
 		}
 
-		UriComponents uriComponents = UriComponentsBuilder.fromUriString(uri).build();
-		TemplateVariables variables = pageableResolver.getPaginationTemplateVariables(getMethodParameter(), uriComponents);
-		resources.add(new Link(new UriTemplate(uri, variables), Link.REL_SELF));
+		resources.add(appendPaginationParameterTemplates(new Link(uri)));
 
 		return resources;
 	}
diff --git a/src/test/java/org/springframework/data/web/PagedResourcesAssemblerUnitTests.java b/src/test/java/org/springframework/data/web/PagedResourcesAssemblerUnitTests.java
index d621f67b4..e335d818b 100644
--- a/src/test/java/org/springframework/data/web/PagedResourcesAssemblerUnitTests.java
+++ b/src/test/java/org/springframework/data/web/PagedResourcesAssemblerUnitTests.java
@@ -55,6 +55,7 @@ public class PagedResourcesAssemblerUnitTests {
 		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(0));
 
 		assertThat(resources.getLink(Link.REL_PREVIOUS), is(nullValue()));
+		assertThat(resources.getLink(Link.REL_SELF), is(notNullValue()));
 		assertThat(resources.getLink(Link.REL_NEXT), is(notNullValue()));
 	}
 
@@ -65,6 +66,7 @@ public class PagedResourcesAssemblerUnitTests {
 		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(1));
 
 		assertThat(resources.getLink(Link.REL_PREVIOUS), is(notNullValue()));
+		assertThat(resources.getLink(Link.REL_SELF), is(notNullValue()));
 		assertThat(resources.getLink(Link.REL_NEXT), is(notNullValue()));
 	}
 
@@ -75,6 +77,7 @@ public class PagedResourcesAssemblerUnitTests {
 		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(2));
 
 		assertThat(resources.getLink(Link.REL_PREVIOUS), is(notNullValue()));
+		assertThat(resources.getLink(Link.REL_SELF), is(notNullValue()));
 		assertThat(resources.getLink(Link.REL_NEXT), is(nullValue()));
 	}
 
@@ -87,6 +90,7 @@ public class PagedResourcesAssemblerUnitTests {
 		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(1));
 
 		assertThat(resources.getLink(Link.REL_PREVIOUS).getHref(), startsWith(baseUri.toUriString()));
+		assertThat(resources.getLink(Link.REL_SELF), is(notNullValue()));
 		assertThat(resources.getLink(Link.REL_NEXT).getHref(), startsWith(baseUri.toUriString()));
 	}
 
@@ -99,6 +103,7 @@ public class PagedResourcesAssemblerUnitTests {
 		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(1), link);
 
 		assertThat(resources.getLink(Link.REL_PREVIOUS).getHref(), startsWith(link.getHref()));
+		assertThat(resources.getLink(Link.REL_SELF), is(notNullValue()));
 		assertThat(resources.getLink(Link.REL_NEXT).getHref(), startsWith(link.getHref()));
 	}
 
@@ -117,6 +122,31 @@ public class PagedResourcesAssemblerUnitTests {
 		assembler.toResource(page);
 	}
 
+	/**
+	 * @see DATACMNS-418
+	 */
+	@Test
+	public void addsSelfLinkWithPaginationTemplateVariables() {
+
+		PagedResourcesAssembler<Person> assembler = new PagedResourcesAssembler<Person>(resolver, null);
+		PagedResources<Resource<Person>> resources = assembler.toResource(createPage(1));
+
+		Link selfLink = resources.getLink(Link.REL_SELF);
+		assertThat(selfLink.getHref(), endsWith("{?page,size,sort}"));
+	}
+
+	/**
+	 * @see DATACMNS-418
+	 */
+	@Test
+	public void appendsMissingTemplateParametersToLink() {
+
+		PagedResourcesAssembler<Person> assembler = new PagedResourcesAssembler<Person>(resolver, null);
+
+		Link link = new Link("/foo?page=0");
+		assertThat(assembler.appendPaginationParameterTemplates(link), is(new Link("/foo?page=0{&size,sort}")));
+	}
+
 	private static Page<Person> createPage(int index) {
 
 		AbstractPageRequest request = new PageRequest(index, 1);