pom.xml

@@ -315,6 +315,24 @@
                 <version>2.4</version>
             </dependency>
 
+            <dependency>
+                <groupId>javax.validation</groupId>
+                <artifactId>validation-api</artifactId>
+                <version>2.0.1.Final</version>
+            </dependency>
+
+            <dependency>
+                <groupId>com.github.victools</groupId>
+                <artifactId>jsonschema-generator</artifactId>
+                <version>${jsonschemagenerator.version}</version>
+            </dependency>
+
+            <dependency>
+                <groupId>com.github.imifou</groupId>
+                <artifactId>jsonschema-module-addon</artifactId>
+                <version>1.2.1</version>
+            </dependency>
+
             <dependency>
                 <groupId>com.fasterxml.jackson.core</groupId>
                 <artifactId>jackson-databind</artifactId>
@@ -389,16 +407,19 @@
             <groupId>javax.persistence</groupId>
             <artifactId>javax.persistence-api</artifactId>
         </dependency>
+
+        <dependency>
+            <groupId>javax.validation</groupId>
+            <artifactId>validation-api</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>com.github.victools</groupId>
             <artifactId>jsonschema-generator</artifactId>
-            <version>${jsonschemagenerator.version}</version>
-<!--            <scope>test</scope>-->
         </dependency>
         <dependency>
             <groupId>com.github.imifou</groupId>
             <artifactId>jsonschema-module-addon</artifactId>
-            <version>1.2.1</version>
         </dependency>
 
     </dependencies>

src/main/java/eu/dnetlib/dhp/schema/oaf/AccessRight.java

@@ -3,11 +3,14 @@ package eu.dnetlib.dhp.schema.oaf;
 
 import java.util.Optional;
 
+import javax.validation.constraints.NotNull;
+
 /**
  * This class models the access rights of research products.
  */
 public class AccessRight extends Qualifier {
 
+	@NotNull
 	private OpenAccessRoute openAccessRoute;
 
 	public OpenAccessRoute getOpenAccessRoute() {

src/main/java/eu/dnetlib/dhp/schema/oaf/Author.java

@@ -4,8 +4,13 @@ package eu.dnetlib.dhp.schema.oaf;
 import java.io.Serializable;
 import java.util.*;
 
+import javax.validation.constraints.Min;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
 public class Author implements Serializable {
 
+	@NotBlank
 	private String fullname;
 
 	private String name;
@@ -13,6 +18,8 @@ public class Author implements Serializable {
 	private String surname;
 
 	// START WITH 1
+	@NotNull
+	@Min(1)
 	private Integer rank;
 
 	private List<StructuredProperty> pid;

src/main/java/eu/dnetlib/dhp/schema/oaf/Context.java

@@ -4,9 +4,15 @@ package eu.dnetlib.dhp.schema.oaf;
 import java.io.Serializable;
 import java.util.List;
 
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
 public class Context implements Serializable {
+
+	@NotBlank
 	private String id;
 
+	@NotNull
 	private List<DataInfo> dataInfo;
 
 	public String getId() {

src/main/java/eu/dnetlib/dhp/schema/oaf/DataInfo.java

@@ -4,13 +4,24 @@ package eu.dnetlib.dhp.schema.oaf;
 import java.io.Serializable;
 import java.util.Objects;
 
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
 public class DataInfo implements Serializable {
 
+	@NotNull
 	private Boolean invisible = false;
+
+	@NotNull
 	private Boolean inferred;
+
+	@NotNull
 	private Boolean deletedbyinference = false;
 	private String trust;
+
 	private String inferenceprovenance;
+
+	@NotNull
 	private Qualifier provenanceaction;
 
 	public Boolean getInvisible() {

src/main/java/eu/dnetlib/dhp/schema/oaf/Field.java

@@ -4,8 +4,11 @@ package eu.dnetlib.dhp.schema.oaf;
 import java.io.Serializable;
 import java.util.Objects;
 
+import javax.validation.constraints.NotBlank;
+
 public class Field<T> implements Serializable {
 
+	@NotBlank
 	private T value;
 
 	private DataInfo dataInfo;

src/main/java/eu/dnetlib/dhp/schema/oaf/Instance.java

@@ -4,21 +4,30 @@ package eu.dnetlib.dhp.schema.oaf;
 import java.io.Serializable;
 import java.util.List;
 
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
 public class Instance implements Serializable {
 
 	private Field<String> license;
 
+	@NotNull
 	private AccessRight accessright;
 
+	@NotNull
 	private Qualifier instancetype;
 
+	@NotNull
 	private KeyValue hostedby;
 
+	@NotEmpty
 	private List<String> url;
 
 	// other research products specifc
 	private String distributionlocation;
 
+	@NotNull
 	private KeyValue collectedfrom;
 
 	private List<StructuredProperty> pid;
@@ -35,6 +44,7 @@ public class Instance implements Serializable {
 	// typed results
 	private Field<String> processingchargecurrency;
 
+	@NotNull
 	private Qualifier refereed; // peer-review status
 
 	private List<Measure> measures;

src/main/java/eu/dnetlib/dhp/schema/oaf/KeyValue.java

@@ -3,14 +3,19 @@ package eu.dnetlib.dhp.schema.oaf;
 
 import java.io.Serializable;
 
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
 import org.apache.commons.lang3.StringUtils;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 public class KeyValue implements Serializable {
 
+	@NotBlank
 	private String key;
 
+	@NotBlank
 	private String value;
 
 	private DataInfo dataInfo;

src/main/java/eu/dnetlib/dhp/schema/oaf/Oaf.java

@@ -9,13 +9,21 @@ import java.util.Optional;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import javax.validation.Valid;
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
 public abstract class Oaf implements Serializable {
 
 	/**
 	 * The list of datasource id/name pairs providing this relationship.
 	 */
+	@Valid
+	@NotEmpty
 	protected List<KeyValue> collectedfrom;
 
+	@Valid
+	@NotNull
 	private DataInfo dataInfo;
 
 	private Long lastupdatetimestamp;

src/main/java/eu/dnetlib/dhp/schema/oaf/OafEntity.java

@@ -5,14 +5,18 @@ import java.io.Serializable;
 import java.util.*;
 import java.util.stream.Collectors;
 
+import javax.validation.constraints.NotBlank;
+
 public abstract class OafEntity extends Oaf implements Serializable {
 
+	@NotBlank
 	private String id;
 
 	private List<String> originalId;
 
 	private List<StructuredProperty> pid;
 
+	@NotBlank
 	private String dateofcollection;
 
 	private String dateoftransformation;

src/main/java/eu/dnetlib/dhp/schema/oaf/Qualifier.java

@@ -3,15 +3,24 @@ package eu.dnetlib.dhp.schema.oaf;
 
 import java.io.Serializable;
 
+import javax.validation.constraints.NotBlank;
+
 import org.apache.commons.lang3.StringUtils;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
 public class Qualifier implements Serializable {
 
+	@NotBlank
 	private String classid;
+
+	@NotBlank
 	private String classname;
+
+	@NotBlank
 	private String schemeid;
+
+	@NotBlank
 	private String schemename;
 
 	public String getClassid() {

src/main/java/eu/dnetlib/dhp/schema/oaf/Relation.java

@@ -8,6 +8,8 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
+import javax.validation.constraints.NotBlank;
+
 import eu.dnetlib.dhp.schema.common.ModelSupport;
 
 /**
@@ -21,27 +23,32 @@ public class Relation extends Oaf {
 	/**
 	 * Main relationship classifier, values include 'resultResult', 'resultProject', 'resultOrganization', etc.
 	 */
+	@NotBlank
 	private String relType;
 
 	/**
 	 * Further classifies a relationship, values include 'affiliation', 'similarity', 'supplement', etc.
 	 */
+	@NotBlank
 	private String subRelType;
 
 	/**
 	 * Indicates the direction of the relationship, values include 'isSupplementTo', 'isSupplementedBy', 'merges,
 	 * 'isMergedIn'.
 	 */
+	@NotBlank
 	private String relClass;
 
 	/**
 	 * The source entity id.
 	 */
+	@NotBlank
 	private String source;
 
 	/**
 	 * The target entity id.
 	 */
+	@NotBlank
 	private String target;
 
 	/**

src/main/java/eu/dnetlib/dhp/schema/oaf/Result.java

@@ -5,6 +5,10 @@ import java.io.Serializable;
 import java.util.*;
 import java.util.stream.Collectors;
 
+import javax.validation.Valid;
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+
 import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.apache.commons.lang3.tuple.Pair;
 
@@ -28,15 +32,15 @@ public class Result extends OafEntity implements Serializable {
 	private List<Author> author;
 
 	/**
-	 * The Resulttype.
+	 * The Resulttype, allows subclassing results into publications | datasets | software
 	 */
-// resulttype allows subclassing results into publications | datasets | software
+	@Valid
+	@NotNull
 	private Qualifier resulttype;
 
 	/**
 	 * The Language.
 	 */
-// common fields
 	private Qualifier language;
 
 	/**
@@ -112,6 +116,8 @@ public class Result extends OafEntity implements Serializable {
 	/**
 	 * The Bestaccessright.
 	 */
+	@Valid
+	@NotNull
 	private Qualifier bestaccessright;
 
 	/**
@@ -127,6 +133,8 @@ public class Result extends OafEntity implements Serializable {
 	/**
 	 * The Instance.
 	 */
+	@Valid
+	@NotEmpty
 	private List<Instance> instance;
 
 	/**

src/main/java/eu/dnetlib/dhp/schema/oaf/StructuredProperty.java

@@ -6,12 +6,17 @@ import java.util.Optional;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.NotNull;
+
 import org.apache.commons.lang3.StringUtils;
 
 public class StructuredProperty implements Serializable {
 
+	@NotBlank
 	private String value;
 
+	@NotNull
 	private Qualifier qualifier;
 
 	private DataInfo dataInfo;