Refactor and fix sub type handling for Content and Answer

We now use the format property instead as type ID for Jackson. A custom
TypeIdResolver is used for the mapping.

src/main/java/de/thm/arsnova/entities/Answer.java

@@ -2,6 +2,8 @@ package de.thm.arsnova.entities;
 
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.annotation.JsonView;
+import com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver;
+import de.thm.arsnova.entities.serialization.FormatAnswerTypeIdResolver;
 import de.thm.arsnova.entities.serialization.View;
 import org.springframework.core.style.ToStringCreator;
 
@@ -9,14 +11,17 @@ import java.util.Map;
 import java.util.Objects;
 
 @JsonTypeInfo(
-		use = JsonTypeInfo.Id.NAME,
-		include = JsonTypeInfo.As.EXISTING_PROPERTY,
-		property = "type"
+		use = JsonTypeInfo.Id.CUSTOM,
+		property = "format",
+		visible = true,
+		defaultImpl = Answer.class
 )
-public abstract class Answer extends Entity {
+@JsonTypeIdResolver(FormatAnswerTypeIdResolver.class)
+public class Answer extends Entity {
 	private String contentId;
 	private String roomId;
 	private String creatorId;
+	private Content.Format format;
 	private int round;
 	private Map<String, Map<String, ?>> extensions;
 
@@ -49,6 +54,16 @@ public abstract class Answer extends Entity {
 		this.creatorId = creatorId;
 	}
 
+	@JsonView({View.Persistence.class, View.Public.class})
+	public Content.Format getFormat() {
+		return format;
+	}
+
+	@JsonView({View.Persistence.class, View.Public.class})
+	public void setFormat(final Content.Format format) {
+		this.format = format;
+	}
+
 	@JsonView({View.Persistence.class, View.Public.class})
 	public int getRound() {
 		return round;
@@ -69,6 +84,12 @@ public abstract class Answer extends Entity {
 		this.extensions = extensions;
 	}
 
+	@JsonView(View.Persistence.class)
+	@Override
+	public Class<? extends Entity> getType() {
+		return Answer.class;
+	}
+
 	/**
 	 * {@inheritDoc}
 	 *
@@ -97,6 +118,7 @@ public abstract class Answer extends Entity {
 				.append("contentId", contentId)
 				.append("roomId", roomId)
 				.append("creatorId", creatorId)
+				.append("format", format)
 				.append("round", round);
 	}
 }

src/main/java/de/thm/arsnova/entities/Content.java

@@ -2,6 +2,8 @@ package de.thm.arsnova.entities;
 
 import com.fasterxml.jackson.annotation.JsonTypeInfo;
 import com.fasterxml.jackson.annotation.JsonView;
+import com.fasterxml.jackson.databind.annotation.JsonTypeIdResolver;
+import de.thm.arsnova.entities.serialization.FormatContentTypeIdResolver;
 import de.thm.arsnova.entities.serialization.View;
 import org.springframework.core.style.ToStringCreator;
 
@@ -12,10 +14,12 @@ import java.util.Objects;
 import java.util.Set;
 
 @JsonTypeInfo(
-		use = JsonTypeInfo.Id.NAME,
-		include = JsonTypeInfo.As.EXISTING_PROPERTY,
-		property = "type"
+		use = JsonTypeInfo.Id.CUSTOM,
+		property = "format",
+		visible = true,
+		defaultImpl = Content.class
 )
+@JsonTypeIdResolver(FormatContentTypeIdResolver.class)
 public class Content extends Entity {
 	public enum Format {
 		CHOICE,
@@ -227,6 +231,12 @@ public class Content extends Entity {
 		this.abstentionsAllowed = abstentionsAllowed;
 	}
 
+	@JsonView(View.Persistence.class)
+	@Override
+	public Class<? extends Entity> getType() {
+		return Content.class;
+	}
+
 	/**
 	 * {@inheritDoc}
 	 *

src/main/java/de/thm/arsnova/entities/serialization/CouchDbDocumentModule.java

@@ -17,14 +17,8 @@
  */
 package de.thm.arsnova.entities.serialization;
 
-import com.fasterxml.jackson.databind.jsontype.NamedType;
 import com.fasterxml.jackson.databind.module.SimpleModule;
-import de.thm.arsnova.entities.Answer;
-import de.thm.arsnova.entities.ChoiceAnswer;
-import de.thm.arsnova.entities.ChoiceQuestionContent;
-import de.thm.arsnova.entities.Content;
 import de.thm.arsnova.entities.Entity;
-import de.thm.arsnova.entities.TextAnswer;
 
 public class CouchDbDocumentModule extends SimpleModule {
 	public CouchDbDocumentModule() {
@@ -35,11 +29,5 @@ public class CouchDbDocumentModule extends SimpleModule {
 	public void setupModule(SetupContext context) {
 		context.setMixInAnnotations(Entity.class, CouchDbDocumentMixIn.class);
 		context.setMixInAnnotations(de.thm.arsnova.entities.migration.v2.Entity.class, CouchDbDocumentV2MixIn.class);
-		context.registerSubtypes(
-				new NamedType(Content.class, Content.class.getSimpleName()),
-				new NamedType(ChoiceQuestionContent.class, ChoiceQuestionContent.class.getSimpleName()),
-				new NamedType(Answer.class, Answer.class.getSimpleName()),
-				new NamedType(ChoiceAnswer.class, ChoiceAnswer.class.getSimpleName()),
-				new NamedType(TextAnswer.class, TextAnswer.class.getSimpleName()));
 	}
 }

src/main/java/de/thm/arsnova/entities/serialization/FormatAnswerTypeIdResolver.java

+package de.thm.arsnova.entities.serialization;
+
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.DatabindContext;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.jsontype.impl.TypeIdResolverBase;
+import com.fasterxml.jackson.databind.type.TypeFactory;
+import de.thm.arsnova.entities.Answer;
+import de.thm.arsnova.entities.ChoiceAnswer;
+import de.thm.arsnova.entities.Content;
+import de.thm.arsnova.entities.TextAnswer;
+
+import java.io.IOException;
+
+public class FormatAnswerTypeIdResolver extends TypeIdResolverBase {
+	@Override
+	public String idFromValue(final Object value) {
+		if (value instanceof Answer) {
+			return ((Answer) value).getFormat().toString();
+		} else {
+			throw new IllegalArgumentException("Unsupported type.");
+		}
+	}
+
+	@Override
+	public String idFromValueAndType(final Object value, final Class<?> suggestedType) {
+		return idFromValue(value);
+	}
+
+	@Override
+	public JavaType typeFromId(final DatabindContext context, final String id) throws IOException {
+		Content.Format format = Content.Format.valueOf(id);
+		switch (format) {
+			case BINARY:
+				return TypeFactory.defaultInstance().constructType(ChoiceAnswer.class);
+			case CHOICE:
+				return TypeFactory.defaultInstance().constructType(ChoiceAnswer.class);
+			case NUMBER:
+				return TypeFactory.defaultInstance().constructType(ChoiceAnswer.class);
+			case SCALE:
+				return TypeFactory.defaultInstance().constructType(ChoiceAnswer.class);
+			case TEXT:
+				return TypeFactory.defaultInstance().constructType(TextAnswer.class);
+			default:
+				throw new IllegalArgumentException("Unsupported type ID.");
+		}
+	}
+
+	@Override
+	public JsonTypeInfo.Id getMechanism() {
+		return JsonTypeInfo.Id.CUSTOM;
+	}
+}

src/main/java/de/thm/arsnova/entities/serialization/FormatContentTypeIdResolver.java

+package de.thm.arsnova.entities.serialization;
+
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.databind.DatabindContext;
+import com.fasterxml.jackson.databind.JavaType;
+import com.fasterxml.jackson.databind.jsontype.impl.TypeIdResolverBase;
+import com.fasterxml.jackson.databind.type.TypeFactory;
+import de.thm.arsnova.entities.ChoiceQuestionContent;
+import de.thm.arsnova.entities.Content;
+
+import java.io.IOException;
+
+public class FormatContentTypeIdResolver extends TypeIdResolverBase {
+	@Override
+	public String idFromValue(final Object value) {
+		if (value instanceof Content) {
+			return ((Content) value).getFormat().toString();
+		} else {
+			throw new IllegalArgumentException("Unsupported type.");
+		}
+	}
+
+	@Override
+	public String idFromValueAndType(final Object value, final Class<?> suggestedType) {
+		return idFromValue(value);
+	}
+
+	@Override
+	public JavaType typeFromId(final DatabindContext context, final String id) throws IOException {
+		Content.Format format = Content.Format.valueOf(id);
+		switch (format) {
+			case BINARY:
+				return TypeFactory.defaultInstance().constructType(ChoiceQuestionContent.class);
+			case CHOICE:
+				return TypeFactory.defaultInstance().constructType(ChoiceQuestionContent.class);
+			case NUMBER:
+				return TypeFactory.defaultInstance().constructType(ChoiceQuestionContent.class);
+			case SCALE:
+				return TypeFactory.defaultInstance().constructType(ChoiceQuestionContent.class);
+			case TEXT:
+				return TypeFactory.defaultInstance().constructType(Content.class);
+			default:
+				throw new IllegalArgumentException("Unsupported type ID.");
+		}
+	}
+
+	@Override
+	public JsonTypeInfo.Id getMechanism() {
+		return JsonTypeInfo.Id.CUSTOM;
+	}
+}

src/main/resources/couchdb/Answer.design.js

@@ -4,7 +4,7 @@ var designDoc = {
 	"views": {
 		"by_id": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit(doc._id, {_rev: doc._rev});
 				}
 			},
@@ -12,14 +12,14 @@ var designDoc = {
 		},
 		"by_contentid": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit(doc.contentId, {_rev: doc._rev});
 				}
 			}
 		},
 		"by_contentid_round_body_subject": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.contentId, doc.round, doc.abstention, doc.body, doc.subject, doc.successfulFreeTextAnswer], {_rev: doc._rev});
 				}
 			},
@@ -27,7 +27,7 @@ var designDoc = {
 		},
 		"by_contentid_round_selectedchoiceindexes": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.contentId, doc.round, doc.selectedChoiceIndexes], {_rev: doc._rev});
 				}
 			},
@@ -35,21 +35,21 @@ var designDoc = {
 		},
 		"by_contentid_creationtimestamp": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.contentId, doc.creationTimestamp], {_rev: doc._rev});
 				}
 			}
 		},
 		"by_contentid_creatorid_round": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.contentId, doc.creatorId, doc.round], {_rev: doc._rev});
 				}
 			}
 		},
 		"by_roomid": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit(doc.roomId, {_rev: doc._rev});
 				}
 			},
@@ -57,7 +57,7 @@ var designDoc = {
 		},
 		"by_roomid_variant": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.roomId, doc.questionVariant], {_rev: doc._rev});
 				}
 			},
@@ -65,21 +65,21 @@ var designDoc = {
 		},
 		"by_creatorid_roomid": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.creatorId, doc.roomId], {_rev: doc._rev});
 				}
 			}
 		},
 		"contentid_by_creatorid_roomid_variant": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.user, doc.roomId, doc.questionVariant], doc.contentId);
 				}
 			}
 		},
 		"contentid_round_by_creatorid_roomid_variant": {
 			"map": function (doc) {
-				if (["Answer", "ChoiceAnswer", "TextAnswer"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Answer") {
 					emit([doc.creatorId, doc.roomId, doc.questionVariant], [doc.contentId, doc.round]);
 				}
 			}

src/main/resources/couchdb/Content.design.js

@@ -4,7 +4,7 @@ var designDoc = {
 	"views": {
 		"by_id": {
 			"map": function (doc) {
-				if (["Content", "ChoiceQuestionContent"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Content") {
 					emit(doc._id, {_rev: doc._rev});
 				}
 			},
@@ -12,7 +12,7 @@ var designDoc = {
 		},
 		"by_roomid": {
 			"map": function (doc) {
-				if (["Content", "ChoiceQuestionContent"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Content") {
 					emit(doc.roomId, {_rev: doc._rev});
 				}
 			},
@@ -20,7 +20,7 @@ var designDoc = {
 		},
 		"by_roomid_group_locked": {
 			"map": function (doc) {
-				if (["Content", "ChoiceQuestionContent"].indexOf(doc.type) !== -1) {
+				if (doc.type === "Content") {
 					emit([doc.roomId, doc.group, doc.locked, doc.subject, doc.body.substr(0, 16)], {_rev: doc._rev});
 				}
 			},