Expose exceptions

wdtk-datamodel/src/main/java/org/wikidata/wdtk/datamodel/helpers/JsonDeserializer.java

@@ -1,5 +1,3 @@
-package org.wikidata.wdtk.datamodel.helpers;
-
 /*-
  * #%L
  * Wikidata Toolkit Data Model
@@ -20,13 +18,24 @@
  * #L%
  */
 
-import java.io.IOException;
+package org.wikidata.wdtk.datamodel.helpers;
 
-import com.fasterxml.jackson.databind.ObjectReader;
-import org.wikidata.wdtk.datamodel.implementation.*;
-import org.wikidata.wdtk.datamodel.interfaces.*;
+import org.wikidata.wdtk.datamodel.implementation.EntityDocumentImpl;
+import org.wikidata.wdtk.datamodel.implementation.EntityRedirectDocumentImpl;
+import org.wikidata.wdtk.datamodel.implementation.ItemDocumentImpl;
+import org.wikidata.wdtk.datamodel.implementation.LexemeDocumentImpl;
+import org.wikidata.wdtk.datamodel.implementation.MediaInfoDocumentImpl;
+import org.wikidata.wdtk.datamodel.implementation.PropertyDocumentImpl;
+import org.wikidata.wdtk.datamodel.interfaces.EntityDocument;
+import org.wikidata.wdtk.datamodel.interfaces.EntityRedirectDocument;
+import org.wikidata.wdtk.datamodel.interfaces.ItemDocument;
+import org.wikidata.wdtk.datamodel.interfaces.LexemeDocument;
+import org.wikidata.wdtk.datamodel.interfaces.MediaInfoDocument;
+import org.wikidata.wdtk.datamodel.interfaces.PropertyDocument;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectReader;
 
 /**
  * Helper to deserialize datamodel objects from their
@@ -72,55 +81,55 @@ public JsonDeserializer(String siteIri) {
 
 	/**
 	 * Deserializes a JSON string into an {@link ItemDocument}.
-	 * @throws IOException 
+	 * @throws JsonProcessingException 
 			if the JSON payload is invalid
 	 */
-	public ItemDocument deserializeItemDocument(String json) throws IOException {
+	public ItemDocument deserializeItemDocument(String json) throws JsonProcessingException {
 		return itemReader.readValue(json);
 	}
 
 	/**
 	 * Deserializes a JSON string into a {@link PropertyDocument}.
-	 * @throws IOException 
+	 * @throws JsonProcessingException 
 			if the JSON payload is invalid
 	 */
-	public PropertyDocument deserializePropertyDocument(String json) throws IOException {
+	public PropertyDocument deserializePropertyDocument(String json) throws JsonProcessingException {
 		return propertyReader.readValue(json);
 	}
 
 	/**
 	 * Deserializes a JSON string into a {@link LexemeDocument}.
-	 * @throws IOException 
+	 * @throws JsonProcessingException 
 			if the JSON payload is invalid
 	 */
-	public LexemeDocument deserializeLexemeDocument(String json) throws IOException {
+	public LexemeDocument deserializeLexemeDocument(String json) throws JsonProcessingException {
 		return lexemeReader.readValue(json);
 	}
 
 	/**
 	 * Deserializes a JSON string into a {@link MediaInfoDocument}.
-	 * @throws IOException 
+	 * @throws JsonProcessingException 
 			if the JSON payload is invalid
 	 */
-	public MediaInfoDocument deserializeMediaInfoDocument(String json) throws IOException {
+	public MediaInfoDocument deserializeMediaInfoDocument(String json) throws JsonProcessingException {
 		return mediaInfoReader.readValue(json);
 	}
 
 	/**
 	 * Deserializes a JSON string into a {@link EntityDocument}.
-	 * @throws IOException 
+	 * @throws JsonProcessingException 
 			if the JSON payload is invalid
 	 */
-	public EntityDocument deserializeEntityDocument(String json) throws IOException {
+	public EntityDocument deserializeEntityDocument(String json) throws JsonProcessingException {
 		return entityDocumentReader.readValue(json);
 	}
 
 	/**
 	 * Deserializes a JSON string into a {@link EntityRedirectDocument}.
-	 * @throws IOException
+	 * @throws JsonProcessingException
 	if the JSON payload is invalid
 	 */
-	public EntityRedirectDocument deserializeEntityRedirectDocument(String json) throws IOException {
+	public EntityRedirectDocument deserializeEntityRedirectDocument(String json) throws JsonProcessingException {
 		return entityRedirectReader.readValue(json);
 	}
 }

wdtk-datamodel/src/main/java/org/wikidata/wdtk/datamodel/helpers/JsonSerializer.java

@@ -1,5 +1,3 @@
-package org.wikidata.wdtk.datamodel.helpers;
-
 /*
  * #%L
  * Wikidata Toolkit Data Model
@@ -20,6 +18,8 @@
  * #L%
  */
 
+package org.wikidata.wdtk.datamodel.helpers;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
@@ -173,69 +173,54 @@ private void serializeEntityDocument(EntityDocument entityDocument) {
 	}
 
 	/**
-	 * Serializes the given object in JSON and returns the resulting string. In
-	 * case of errors, null is returned.
+	 * Serializes the given object in JSON and returns the resulting string.
+	 * Throws if the serialization fails.
 	 *
 	 * @param itemDocument
 	 *            object to serialize
-	 * @return JSON serialization or null
+	 * @return JSON serialization
+	 * @throws JsonProcessingException if the object cannot be serialized
 	 */
-	public static String getJsonString(ItemDocument itemDocument) {
-		return jacksonObjectToString(itemDocument);
+	public static String getJsonString(ItemDocument itemDocument) throws JsonProcessingException {
+		return mapper.writeValueAsString(itemDocument);
 	}
 
 	/**
-	 * Serializes the given object in JSON and returns the resulting string. In
-	 * case of errors, null is returned.
+	 * Serializes the given object in JSON and returns the resulting string.
+	 * Throws if the serialization fails.
 	 *
 	 * @param propertyDocument
 	 *            object to serialize
-	 * @return JSON serialization or null
+	 * @return JSON serialization
+	 * @throws JsonProcessingException if the object cannot be serialized
 	 */
-	public static String getJsonString(PropertyDocument propertyDocument) {
-		return jacksonObjectToString(propertyDocument);
+	public static String getJsonString(PropertyDocument propertyDocument) throws JsonProcessingException {
+		return mapper.writeValueAsString(propertyDocument);
 	}
 
 	/**
-	 * Serializes the given object in JSON and returns the resulting string. In
-	 * case of errors, null is returned.
+	 * Serializes the given object in JSON and returns the resulting string.
+	 * Throws if the serialization fails.
 	 *
 	 * @param mediaInfoDocument
 	 *            object to serialize
-	 * @return JSON serialization or null
+	 * @return JSON serialization
+	 * @throws JsonProcessingException if the object cannot be serialized
 	 */
-	public static String getJsonString(MediaInfoDocument mediaInfoDocument) {
-		return jacksonObjectToString(mediaInfoDocument);
+	public static String getJsonString(MediaInfoDocument mediaInfoDocument) throws JsonProcessingException {
+		return mapper.writeValueAsString(mediaInfoDocument);
 	}
 
 	/**
-	 * Serializes the given object in JSON and returns the resulting string. In
-	 * case of errors, null is returned.
+	 * Serializes the given object in JSON and returns the resulting string.
+	 * Throws if the serialization fails.
 	 *
 	 * @param statement
 	 *            object to serialize
-	 * @return JSON serialization or null
-	 */
-	public static String getJsonString(Statement statement) {
-		return jacksonObjectToString(statement);
-	}
-
-	/**
-	 * Serializes the given object in JSON and returns the resulting string. In
-	 * case of errors, null is returned. In particular, this happens if the
-	 * object is not based on a Jackson-annotated class. An error is logged in
-	 * this case.
-	 *
-	 * @param object
-	 *            object to serialize
-	 * @return JSON serialization or null
+	 * @return JSON serialization
+	 * @throws JsonProcessingException if the object cannot be serialized
 	 */
-	protected static String jacksonObjectToString(Object object) {
-		try {
-			return mapper.writeValueAsString(object);
-		} catch (JsonProcessingException e) {
-			logger.error("Failed to serialize JSON data: " + e.toString());
-			return null;
-		}
+	public static String getJsonString(Statement statement) throws JsonProcessingException {
+		return mapper.writeValueAsString(statement);
 	}
 }

wdtk-datamodel/src/test/java/org/wikidata/wdtk/datamodel/helpers/JsonSerializerTest.java

@@ -21,14 +21,16 @@
 package org.wikidata.wdtk.datamodel.helpers;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 
 import org.junit.jupiter.api.Test;
 import org.wikidata.wdtk.datamodel.implementation.EntityDocumentImpl;
@@ -37,10 +39,14 @@
 import org.wikidata.wdtk.datamodel.interfaces.EntityDocument;
 import org.wikidata.wdtk.datamodel.interfaces.ItemDocument;
 import org.wikidata.wdtk.datamodel.interfaces.ItemIdValue;
+import org.wikidata.wdtk.datamodel.interfaces.MonolingualTextValue;
 import org.wikidata.wdtk.datamodel.interfaces.PropertyDocument;
+import org.wikidata.wdtk.datamodel.interfaces.SiteLink;
 import org.wikidata.wdtk.datamodel.interfaces.Statement;
+import org.wikidata.wdtk.datamodel.interfaces.StatementGroup;
 import org.wikidata.wdtk.datamodel.interfaces.StatementRank;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.MappingIterator;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.ObjectReader;
@@ -97,7 +103,7 @@ public void testSerializer() throws IOException {
 	}
 
 	@Test
-	public void testItemDocumentToJson() {
+	public void testItemDocumentToJson() throws JsonProcessingException {
 		ItemDocument id = Datamodel.makeItemDocument(
 				Datamodel.makeWikidataItemIdValue("Q42"),
 				Collections.emptyList(),
@@ -110,7 +116,7 @@ public void testItemDocumentToJson() {
 	}
 
 	@Test
-	public void testPropertyDocumentToJson() {
+	public void testPropertyDocumentToJson() throws JsonProcessingException {
 		PropertyDocument pd = Datamodel.makePropertyDocument(
 				Datamodel.makeWikidataPropertyIdValue("P1"),
 				Collections. emptyList(),
@@ -123,7 +129,7 @@ Collections. emptyList(),
 	}
 
 	@Test
-	public void testStatementToJson() {
+	public void testStatementToJson() throws JsonProcessingException {
 		Statement s = Datamodel.makeStatement(ItemIdValue.NULL,
 				Datamodel.makeNoValueSnak(Datamodel.makeWikidataPropertyIdValue("P1")),
 				Collections.emptyList(), Collections.emptyList(),
@@ -134,14 +140,74 @@ public void testStatementToJson() {
 
 	@Test
 	public void testJacksonObjectToJsonError() {
-		Object obj = new Object() {
-			@SuppressWarnings("unused")
-			public String getData() {
-				throw new RuntimeException("Test exception");
+		ItemDocument obj = new ItemDocument() {
+
+			@Override
+			public List<StatementGroup> getStatementGroups() {
+				return null;
+			}
+
+			@Override
+			public long getRevisionId() {
+				return 0;
+			}
+
+			@Override
+			public Map<String, MonolingualTextValue> getLabels() {
+				return null;
+			}
+
+			@Override
+			public Map<String, MonolingualTextValue> getDescriptions() {
+				return null;
+			}
+
+			@Override
+			public Map<String, List<MonolingualTextValue>> getAliases() {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withoutStatementIds(Set<String> statementIds) {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withStatement(Statement statement) {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withRevisionId(long newRevisionId) {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withLabel(MonolingualTextValue newLabel) {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withDescription(MonolingualTextValue newDescription) {
+				return null;
+			}
+
+			@Override
+			public ItemDocument withAliases(String language, List<MonolingualTextValue> aliases) {
+				return null;
+			}
+
+			@Override
+			public Map<String, SiteLink> getSiteLinks() {
+				return null;
+			}
+
+			@Override
+			public ItemIdValue getEntityId() {
+				return null;
 			}
 		};
 
-		String result = JsonSerializer.jacksonObjectToString(obj);
-		assertNull(result);
+		assertThrows(JsonProcessingException.class, () -> JsonSerializer.getJsonString(obj));
 	}
 }