Added pagination for instances listing

src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/EntityManagement.java

@@ -38,6 +38,8 @@ import org.gcube.informationsystem.resourceregistry.instances.base.entities.Enti
 import org.gcube.informationsystem.resourceregistry.instances.model.ERManagement;
 import org.gcube.informationsystem.resourceregistry.instances.model.Operation;
 import org.gcube.informationsystem.resourceregistry.instances.model.relations.RelationManagement;
+import org.gcube.informationsystem.resourceregistry.requests.RequestUtility;
+import org.gcube.informationsystem.resourceregistry.requests.ServerRequestInfo;
 import org.gcube.informationsystem.resourceregistry.types.TypesCache;
 import org.gcube.informationsystem.resourceregistry.utils.MetadataUtility;
 import org.gcube.informationsystem.resourceregistry.utils.OrientDBUtility;
@@ -496,19 +498,34 @@ public abstract class EntityManagement<E extends Entity, ET extends EntityType>
 		ObjectMapper objectMapper = new ObjectMapper();
 		ArrayNode arrayNode = objectMapper.createArrayNode();
 		
+		ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
+		int limit = requestInfo.getLimit();
+		int offset = requestInfo.getOffset();
+		
+		int position = -1;
+		int count = 0;
+		
 		Iterable<ODocument> iterable = oDatabaseDocument.browseClass(typeName, polymorphic);
 		for(ODocument vertex : iterable) {
+			if(++position < offset) {
+				continue;
+			}
+			
 			EntityManagement<?,?> entityManagement = ElementManagementUtility.getEntityManagement(getWorkingContext(),
 					oDatabaseDocument, (OVertex) vertex);
 			try {
 				entityManagement.setAsEntryPoint();
 				JsonNode jsonNode = entityManagement.serializeAsJsonNode();
 				arrayNode.add(jsonNode);
+				if(++count >= limit) {
+					break;
+				}
 			} catch(ResourceRegistryException e) {
 				logger.error("Unable to correctly serialize {}. It will be excluded from results. {}",
 						vertex.toString(), OrientDBUtility.SHOULD_NOT_OCCUR_ERROR_MESSAGE);
 			}
 		}
+		
 		try {
 			return objectMapper.writeValueAsString(arrayNode);
 		} catch(JsonProcessingException e) {

src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/relations/RelationManagement.java

@@ -39,6 +39,8 @@ import org.gcube.informationsystem.resourceregistry.instances.model.Operation;
 import org.gcube.informationsystem.resourceregistry.instances.model.entities.EntityManagement;
 import org.gcube.informationsystem.resourceregistry.instances.model.entities.FacetManagement;
 import org.gcube.informationsystem.resourceregistry.instances.model.entities.ResourceManagement;
+import org.gcube.informationsystem.resourceregistry.requests.RequestUtility;
+import org.gcube.informationsystem.resourceregistry.requests.ServerRequestInfo;
 import org.gcube.informationsystem.resourceregistry.types.TypesCache;
 import org.gcube.informationsystem.resourceregistry.utils.MetadataUtility;
 import org.gcube.informationsystem.resourceregistry.utils.OrientDBUtility;
@@ -777,11 +779,23 @@ public abstract class RelationManagement<T extends EntityManagement<? extends En
 		
 	}
 	
-	protected Collection<JsonNode> serializeEdges(Iterable<ODocument> edges, boolean postFilterPolymorphic)
+	private Collection<JsonNode> serializeEdges(Iterable<ODocument> edges, boolean postFilterPolymorphic)
 			throws ResourceRegistryException {
+		
+		ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
+		int limit = requestInfo.getLimit();
+		int offset = requestInfo.getOffset();
+		
+		int position = -1;
+		int count = 0;
+		
 		// Map<String,JsonNode> visitedSourceResources = new HashMap<>();
 		List<JsonNode> serilizedEdges = new ArrayList<>();
 		for(ODocument d : edges) {
+			if(++position < offset) {
+				continue;
+			}
+			
 			OEdge edge = (OEdge) d;
 			
 			if(postFilterPolymorphic && getOClass().isSubClassOf(typeName)) {
@@ -792,6 +806,9 @@ public abstract class RelationManagement<T extends EntityManagement<? extends En
 					oDatabaseDocument, edge);
 			// visitedSourceResources = relationManagement.fullSerialize(visitedSourceResources);
 			serilizedEdges.add(relationManagement.serializeAsJsonNode());
+			if(++count >= limit) {
+				break;
+			}
 		}
 		return serilizedEdges;
 	}

src/main/java/org/gcube/informationsystem/resourceregistry/rest/Access.java

@@ -220,6 +220,7 @@ public class Access extends BaseRest {
 		
 		ServerRequestInfo serverRequestInfo = initRequestInfo();
 		serverRequestInfo.checkAllBooleanQueryParameters();
+		serverRequestInfo.checkLimitOffset();
 		
 		ElementManagement<?,?> erManagement = ElementManagementUtility.getERManagement(type);
 		return erManagement.all(polymorphic);

src/test/java/org/gcube/informationsystem/resourceregistry/instances/ERManagementTest.java

@@ -3,15 +3,20 @@
  */
 package org.gcube.informationsystem.resourceregistry.instances;
 
+import java.io.IOException;
 import java.net.URI;
 import java.net.URL;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.UUID;
 
+import org.gcube.com.fasterxml.jackson.core.JsonParseException;
+import org.gcube.com.fasterxml.jackson.databind.JsonMappingException;
 import org.gcube.common.encryption.encrypter.StringEncrypter;
 import org.gcube.informationsystem.base.reference.IdentifiableElement;
 import org.gcube.informationsystem.model.impl.properties.EncryptedImpl;
@@ -115,6 +120,8 @@ public class ERManagementTest extends ContextTest {
 		ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
 		requestInfo.setIncludeMeta(true);
 		requestInfo.setAllMeta(true);
+		requestInfo.setLimit(1000);
+		requestInfo.setOffset(0);
 	}
 	
 	public static SoftwareFacet getSoftwareFacet() {
@@ -730,4 +737,72 @@ public class ERManagementTest extends ContextTest {
 		logger.debug("{}", ret);
 	}
 	
+	
+	@Test
+	public void testLimitOffsetWithHostingNode() throws ResourceRegistryException, JsonParseException, JsonMappingException, IOException {
+		ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
+		int limit = 2;
+		requestInfo.setLimit(limit);
+		requestInfo.setOffset(0);
+		
+		ResourceManagement resourceManagement = new ResourceManagement();
+		resourceManagement.setElementType(HostingNode.NAME);
+		String ret = resourceManagement.all(true);
+		logger.debug("{}", ret);
+		
+		List<HostingNode> list = ElementMapper.unmarshalList(HostingNode.class, ret);
+		if(list.size()==0) {
+			return;
+		}
+		Assert.assertTrue(list.size() < 3);
+		
+		if(list.size()<2) {
+			return;
+		}
+		
+		Set<UUID> uuids = new HashSet<>();
+		for(HostingNode hn : list) {
+			UUID uuid = hn.getID();
+			uuids.add(uuid);
+			logger.debug("Found {} with UUID {}", HostingNode.NAME, uuid);
+		}
+		
+		requestInfo.setOffset(2);
+		ret = resourceManagement.all(true);
+		logger.debug("{}", ret);
+		list = ElementMapper.unmarshalList(HostingNode.class, ret);
+		if(list.size()>0) {
+			Assert.assertTrue(list.size() < 3);
+			
+			for(HostingNode hn : list) {
+				UUID uuid = hn.getID();
+				Assert.assertFalse(uuids.contains(uuid));
+				uuids.add(uuid);
+				logger.debug("Found {} with UUID {}", HostingNode.NAME, uuid);
+			}
+			
+			if(list.size()<2) {
+				return;
+			}
+			
+			
+			int doubleLimit = limit*2;
+			requestInfo.setOffset(0);
+			requestInfo.setLimit(doubleLimit);
+			ret = resourceManagement.all(true);
+			logger.debug("{}", ret);
+			list = ElementMapper.unmarshalList(HostingNode.class, ret);
+			
+			Assert.assertTrue(list.size() <= doubleLimit);
+			
+			for(HostingNode hn : list) {
+				UUID uuid = hn.getID();
+				logger.debug("Checking if {} with UUID {} was containe din the previous queries", HostingNode.NAME, uuid);
+				Assert.assertTrue(uuids.contains(uuid));
+				logger.debug("As expected got {} with UUID {}", HostingNode.NAME, uuid);
+			}
+		}
+		
+		
+	}
 }