#1443 - Expose affordance input media type in HAL FORMS contentType attribute.

Fixed the contentType in HalFormsTemplate to only contain a single media type.

Also adapted HalFormsAffordanceModelFactory to the new API introduced for #1441.

src/main/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsAffordanceModel.java

@@ -15,12 +15,8 @@
  */
 package org.springframework.hateoas.mediatype.hal.forms;
 
-import java.util.List;
-
 import org.springframework.hateoas.AffordanceModel;
-import org.springframework.hateoas.Link;
-import org.springframework.hateoas.QueryParameter;
-import org.springframework.http.HttpMethod;
+import org.springframework.hateoas.mediatype.ConfiguredAffordance;
 import org.springframework.http.MediaType;
 
 /**
@@ -31,8 +27,8 @@ import org.springframework.http.MediaType;
  */
 class HalFormsAffordanceModel extends AffordanceModel {
 
-	public HalFormsAffordanceModel(String name, Link link, HttpMethod httpMethod, InputPayloadMetadata inputType,
-			List<QueryParameter> queryMethodParameters, PayloadMetadata outputType) {
-		super(name, link, httpMethod, inputType, queryMethodParameters, outputType);
+	public HalFormsAffordanceModel(ConfiguredAffordance configured) {
+		super(configured.getNameOrDefault(), configured.getTarget(), configured.getMethod(), configured.getInputMetadata(),
+				configured.getQueryParameters(), configured.getOutputMetadata());
 	}
 }

src/main/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsAffordanceModelFactory.java

@@ -15,16 +15,10 @@
  */
 package org.springframework.hateoas.mediatype.hal.forms;
 
-import java.util.List;
-
 import org.springframework.hateoas.AffordanceModel;
-import org.springframework.hateoas.AffordanceModel.InputPayloadMetadata;
-import org.springframework.hateoas.AffordanceModel.PayloadMetadata;
-import org.springframework.hateoas.Link;
 import org.springframework.hateoas.MediaTypes;
-import org.springframework.hateoas.QueryParameter;
 import org.springframework.hateoas.mediatype.AffordanceModelFactory;
-import org.springframework.http.HttpMethod;
+import org.springframework.hateoas.mediatype.ConfiguredAffordance;
 import org.springframework.http.MediaType;
 
 /**
@@ -39,12 +33,11 @@ class HalFormsAffordanceModelFactory implements AffordanceModelFactory {
 
 	/*
 	 * (non-Javadoc)
-	 * @see org.springframework.hateoas.AffordanceModelFactory#getAffordanceModel(java.lang.String, org.springframework.hateoas.Link, org.springframework.http.HttpMethod, org.springframework.core.ResolvableType, java.util.List, org.springframework.core.ResolvableType)
+	 * @see org.springframework.hateoas.mediatype.AffordanceModelFactory#getAffordanceModel(org.springframework.hateoas.mediatype.ConfiguredAffordance)
 	 */
 	@Override
-	public AffordanceModel getAffordanceModel(String name, Link link, HttpMethod httpMethod,
-			InputPayloadMetadata inputType, List<QueryParameter> parameters, PayloadMetadata outputType) {
-		return new HalFormsAffordanceModel(name, link, httpMethod, inputType, parameters, outputType);
+	public AffordanceModel getAffordanceModel(ConfiguredAffordance configured) {
+		return new HalFormsAffordanceModel(configured);
 	}
 
 	public MediaType getMediaType() {

src/main/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsTemplate.java

@@ -21,12 +21,10 @@ import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
-import org.springframework.hateoas.mediatype.hal.forms.HalFormsDeserializers.MediaTypesDeserializer;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
@@ -34,7 +32,6 @@ import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonInclude.Include;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 
 /**
  * Value object for a HAL-FORMS template. Describes the available state transition details.
@@ -53,21 +50,21 @@ final class HalFormsTemplate {
 	private String title;
 	private HttpMethod httpMethod;
 	private List<HalFormsProperty> properties;
-	private List<MediaType> contentTypes;
+	private MediaType contentType;
 	private String target;
 
 	@SuppressWarnings("null")
 	private HalFormsTemplate() {
-		this(null, null, Collections.emptyList(), Collections.emptyList(), null);
+		this(null, null, Collections.emptyList(), null, null);
 	}
 
 	private HalFormsTemplate(String title, HttpMethod httpMethod, List<HalFormsProperty> properties,
-			List<MediaType> contentTypes, String target) {
+			@Nullable MediaType contentType, String target) {
 
 		this.title = title;
 		this.httpMethod = httpMethod;
 		this.properties = properties;
-		this.contentTypes = contentTypes;
+		this.contentType = contentType;
 		this.target = target;
 	}
 
@@ -78,13 +75,13 @@ final class HalFormsTemplate {
 	HalFormsTemplate withTitle(String title) {
 
 		return this.title == title ? this
-				: new HalFormsTemplate(title, this.httpMethod, this.properties, this.contentTypes, this.target);
+				: new HalFormsTemplate(title, this.httpMethod, this.properties, this.contentType, this.target);
 	}
 
 	private HalFormsTemplate withHttpMethod(HttpMethod httpMethod) {
 
 		return this.httpMethod == httpMethod ? this
-				: new HalFormsTemplate(this.title, httpMethod, this.properties, this.contentTypes, this.target);
+				: new HalFormsTemplate(this.title, httpMethod, this.properties, this.contentType, this.target);
 	}
 
 	/**
@@ -100,53 +97,35 @@ final class HalFormsTemplate {
 		List<HalFormsProperty> properties = new ArrayList<>(this.properties);
 		properties.add(property);
 
-		return new HalFormsTemplate(title, httpMethod, properties, contentTypes, target);
+		return new HalFormsTemplate(title, httpMethod, properties, contentType, target);
 	}
 
 	HalFormsTemplate withProperties(List<HalFormsProperty> properties) {
 
 		return this.properties == properties ? this
-				: new HalFormsTemplate(title, httpMethod, properties, contentTypes, target);
+				: new HalFormsTemplate(title, httpMethod, properties, contentType, target);
 	}
 
-	/**
-	 * Returns a new {@link HalFormsTemplate} with the given {@link MediaType} added as content type.
-	 *
-	 * @param mediaType must not be {@literal null}.
-	 * @return
-	 */
-	HalFormsTemplate andContentType(MediaType mediaType) {
+	HalFormsTemplate withContentType(@Nullable MediaType contentType) {
 
-		Assert.notNull(mediaType, "Media type must not be null!");
-
-		List<MediaType> contentTypes = new ArrayList<>(this.contentTypes);
-		contentTypes.add(mediaType);
-
-		return new HalFormsTemplate(title, httpMethod, properties, contentTypes, target);
-	}
-
-	HalFormsTemplate withContentTypes(List<MediaType> contentTypes) {
-
-		return this.contentTypes == contentTypes ? this
-				: new HalFormsTemplate(title, httpMethod, properties, contentTypes, target);
+		return this.contentType == contentType ? this
+				: new HalFormsTemplate(title, httpMethod, properties, contentType, target);
 	}
 
 	HalFormsTemplate withTarget(String target) {
 
 		return this.target == target ? this
-				: new HalFormsTemplate(title, httpMethod, properties, contentTypes, target);
+				: new HalFormsTemplate(title, httpMethod, properties, contentType, target);
 	}
 
-	// Jackson helper methods to create the right representation format
-
+	@Nullable
 	@JsonInclude(Include.NON_EMPTY)
 	String getContentType() {
-		return StringUtils.collectionToDelimitedString(contentTypes, ", ");
+		return contentType == null ? null : contentType.toString();
 	}
 
-	@JsonDeserialize(using = MediaTypesDeserializer.class)
-	void setContentType(List<MediaType> mediaTypes) {
-		this.contentTypes = mediaTypes;
+	void setContentType(MediaType mediaType) {
+		this.contentType = mediaType;
 	}
 
 	@Nullable
@@ -173,10 +152,6 @@ final class HalFormsTemplate {
 		return this.properties;
 	}
 
-	List<MediaType> getContentTypes() {
-		return this.contentTypes;
-	}
-
 	@JsonInclude(Include.NON_EMPTY)
 	String getTitle() {
 		return this.title;
@@ -207,7 +182,7 @@ final class HalFormsTemplate {
 		return Objects.equals(this.title, that.title) //
 				&& this.httpMethod == that.httpMethod //
 				&& Objects.equals(this.properties, that.properties) //
-				&& Objects.equals(this.contentTypes, that.contentTypes);
+				&& Objects.equals(this.contentType, that.contentType);
 	}
 
 	/*
@@ -216,7 +191,7 @@ final class HalFormsTemplate {
 	 */
 	@Override
 	public int hashCode() {
-		return Objects.hash(this.title, this.httpMethod, this.properties, this.contentTypes);
+		return Objects.hash(this.title, this.httpMethod, this.properties, this.contentType);
 	}
 
 	/*
@@ -226,6 +201,6 @@ final class HalFormsTemplate {
 	@Override
 	public String toString() {
 		return "HalFormsTemplate(title=" + this.title + ", httpMethod=" + this.httpMethod + ", properties="
-				+ this.properties + ", contentTypes=" + this.contentTypes + ")";
+				+ this.properties + ", contentTypes=" + this.contentType + ")";
 	}
 }

src/main/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsTemplateBuilder.java

@@ -67,7 +67,8 @@ class HalFormsTemplateBuilder {
 				.forEach(it -> {
 
 					HalFormsTemplate template = HalFormsTemplate.forMethod(it.getHttpMethod()) //
-							.withProperties(factory.createProperties(it));
+							.withProperties(factory.createProperties(it))
+							.withContentType(it.getInput().getPrimaryMediaType());
 
 					String target = it.getLink().getHref();
 
@@ -80,7 +81,6 @@ class HalFormsTemplateBuilder {
 				});
 
 		return templates;
-
 	}
 
 	private HalFormsTemplate applyTo(HalFormsTemplate template, HalFormsTemplateBuilder.TemplateTitle templateTitle) {

src/test/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsMessageConverterUnitTest.java

@@ -111,7 +111,7 @@ class HalFormsMessageConverterUnitTest {
 
 		HalFormsTemplate template = HalFormsTemplate.forMethod(HttpMethod.GET) //
 				.withTitle("HAL-FORMS unit test") //
-				.andContentType(MediaTypes.HAL_JSON) //
+				.withContentType(MediaTypes.HAL_JSON) //
 				.andProperty(property); //
 
 		HalFormsDocument expected = HalFormsDocument.empty() //

src/test/java/org/springframework/hateoas/mediatype/hal/forms/HalFormsTemplateBuilderUnitTest.java

@@ -37,6 +37,7 @@ import org.springframework.hateoas.RepresentationModel;
 import org.springframework.hateoas.mediatype.Affordances;
 import org.springframework.hateoas.mediatype.MessageResolver;
 import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
 
 /**
  * @author Oliver Drotbohm
@@ -131,6 +132,24 @@ class HalFormsTemplateBuilderUnitTest {
 		assertThat(templates.get("default").getTarget()).isEqualTo("/example");
 	}
 
+	@Test // #1443
+	void exposesInputMediaTypeAsContentType() {
+
+		MediaType mediaType = MediaType.parseMediaType("text/uri-list");
+
+		Link link = Affordances.of(Link.of("/example", LinkRelation.of("create"))) //
+				.afford(HttpMethod.POST) //
+				.withInput(Payload.class) //
+				.withInputMediaType(mediaType) //
+				.withName("create") //
+				.toLink();
+
+		Map<String, HalFormsTemplate> templates = new HalFormsTemplateBuilder(new HalFormsConfiguration(),
+				MessageResolver.DEFAULTS_ONLY).findTemplates(new RepresentationModel<>().add(link));
+
+		assertThat(templates.get("default").getContentType()).isEqualTo(mediaType.toString());
+	}
+
 	@Getter
 	static class PatternExample extends RepresentationModel<PatternExample> {