Added pagination to contexts

src/main/java/org/gcube/informationsystem/resourceregistry/contexts/ServerContextCache.java

@@ -85,7 +85,9 @@ public class ServerContextCache extends ContextCache {
 			@Override
 			public List<Context> renew() throws ResourceRegistryException {
 				ContextManagement contextManagement = new ContextManagement();
-				String contextsJsonString = contextManagement.allFromServer(false);
+				contextManagement.setForceOffset(0);
+				contextManagement.setForceLimit(-1);
+				String contextsJsonString = contextManagement.allFromDatabase(false);
 				List<Context> contexts = null;
 				try {
 					contexts = ElementMapper.unmarshalList(contextsJsonString);

src/main/java/org/gcube/informationsystem/resourceregistry/contexts/entities/ContextManagement.java

@@ -1,5 +1,6 @@
 package org.gcube.informationsystem.resourceregistry.contexts.entities;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -33,6 +34,8 @@ import org.gcube.informationsystem.resourceregistry.contexts.security.SecurityCo
 import org.gcube.informationsystem.resourceregistry.instances.base.entities.EntityElementManagement;
 import org.gcube.informationsystem.resourceregistry.queries.operators.QueryConditionalOperator;
 import org.gcube.informationsystem.resourceregistry.queries.operators.QueryLogicalOperator;
+import org.gcube.informationsystem.resourceregistry.requests.RequestUtility;
+import org.gcube.informationsystem.resourceregistry.requests.ServerRequestInfo;
 import org.gcube.informationsystem.resourceregistry.utils.OrientDBUtility;
 import org.gcube.informationsystem.serialization.ElementMapper;
 import org.gcube.informationsystem.types.reference.entities.EntityType;
@@ -56,6 +59,16 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 	private static Logger logger = LoggerFactory.getLogger(ContextManagement.class);
 
 	protected String name;
+	protected Integer forceOffset;
+	protected Integer forceLimit;
+	
+	public void setForceOffset(Integer forceOffset) {
+		this.forceOffset = forceOffset;
+	}
+
+	public void setForceLimit(Integer forceLimit) {
+		this.forceLimit = forceLimit;
+	}
 
 	private void init() {
 		this.ignoreStartWithKeys.add(Context.PARENT_PROPERTY);
@@ -63,6 +76,8 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 		this.typeName = Context.NAME;
 		this.forceIncludeMeta = true;
 		this.forceIncludeAllMeta = true;
+		this.forceOffset = null;
+		this.forceLimit = null;
 	}
 
 	public ContextManagement() {
@@ -412,8 +427,27 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 	public String reallyGetAll(boolean polymorphic) throws ResourceRegistryException {
 		ObjectMapper objectMapper = new ObjectMapper();
 		ArrayNode arrayNode = objectMapper.createArrayNode();
+		
+		ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
+		int limit = requestInfo.getLimit();
+		if(forceLimit!=null) {
+			limit = forceLimit;
+		}
+		
+		int offset = requestInfo.getOffset();
+		if(forceOffset!=null) {
+			offset = forceOffset;
+		}
+		
+		int position = -1;
+		int count = 0;
+		
 		Iterable<ODocument> iterable = oDatabaseDocument.browseClass(typeName, polymorphic);
 		for (ODocument vertex : iterable) {
+			if(++position < offset) {
+				continue;
+			}
+			
 			ContextManagement contextManagement = new ContextManagement();
 			contextManagement.setForceIncludeMeta(forceIncludeMeta);
 			contextManagement.setForceIncludeAllMeta(forceIncludeAllMeta);
@@ -421,6 +455,9 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 			try {
 				JsonNode jsonObject = contextManagement.serializeAsJsonNode();
 				arrayNode.add(jsonObject);
+				if(limit > 0 && ++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);
@@ -433,7 +470,7 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 		}
 	}
 
-	public String allFromServer(boolean polymorphic) throws ResourceRegistryException {
+	public String allFromDatabase(boolean polymorphic) throws ResourceRegistryException {
 		return super.all(polymorphic);
 	}
 
@@ -442,9 +479,41 @@ public class ContextManagement extends EntityElementManagement<Context, EntityTy
 		try {
 			ServerContextCache contextCache = ServerContextCache.getInstance();
 			List<Context> contexts = contextCache.getContexts();
+			
+			ServerRequestInfo requestInfo = RequestUtility.getRequestInfo().get();
+			int limit = requestInfo.getLimit();
+			if(forceLimit!=null) {
+				limit = forceLimit;
+			}
+			
+			int offset = requestInfo.getOffset();
+			if(forceOffset!=null) {
+				offset = forceOffset;
+			}
+			
+			int position = -1;
+			int count = 0;
+			
+			if(offset==0 && limit<=0) {
 				return ElementMapper.marshal(contexts);
+			}
+			
+			List<Context> requestedContexts = new ArrayList<>();
+			for (Context c : contexts) {
+				if(++position < offset) {
+					continue;
+				}
+				
+				requestedContexts.add(c);
+				
+				if(limit > 0 && ++count >= limit) {
+					break;
+				}
+			}
+			
+			return ElementMapper.marshal(requestedContexts);
 		} catch (JsonProcessingException | ResourceRegistryException e) {
-			return allFromServer(polymorphic);
+			return allFromDatabase(polymorphic);
 		}
 	}
 

src/test/java/org/gcube/informationsystem/resourceregistry/contexts/ContextManagementTest.java

@@ -1,8 +1,10 @@
 package org.gcube.informationsystem.resourceregistry.contexts;
 
 import java.io.IOException;
+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.JsonProcessingException;
@@ -441,7 +443,13 @@ public class ContextManagementTest extends ContextTest {
 	}
 	
 	private List<Context> getAll() throws Exception {
+		return getAll(0, -1);
+	}
+	
+	private List<Context> getAll(Integer forceOffset, Integer forcelimit) throws Exception {
 		ContextManagement contextManagement = new ContextManagement();
+		contextManagement.setForceOffset(forceOffset);
+		contextManagement.setForceLimit(forcelimit);
 		String allString = contextManagement.all(false);
 		logger.trace(allString);
 		List<Context> all = ElementMapper.unmarshalList(Context.class, allString);
@@ -494,11 +502,10 @@ public class ContextManagementTest extends ContextTest {
 		delete(context);
 	}
 	
-	
 	@Test
 	public void testContextCache() throws Exception {
 		List<Context> contexts = getAll();
-		logger.debug("{}", contexts);
+		logger.info("{}", contexts);
 		
 		ServerContextCache contextCache = ServerContextCache.getInstance();
 		Map<UUID, String> uuidToContextFullName = contextCache.getUUIDToContextFullNameAssociation();
@@ -537,4 +544,66 @@ public class ContextManagementTest extends ContextTest {
 			logger.debug("{} - {} : {}", uuid, fullName, context);
 		}
 	}
+	
+	@Test
+	public void testLimitOffset() throws Exception {
+		int limit = 2;
+		
+		List<Context> contexts = getAll(0, limit);
+		if(contexts.size()==0) {
+			return;
+		}
+		Assert.assertTrue(contexts.size() <= limit);
+		
+		if(contexts.size()< limit) {
+			return;
+		}
+		
+		Set<UUID> uuids = new HashSet<>();
+		for(Context context : contexts) {
+			UUID uuid = context.getID();
+			uuids.add(uuid);
+			logger.info("Found {} with UUID {} and name {}", Context.NAME, uuid, context.getName());
+		}
+		
+		contexts = getAll(limit, limit);
+		
+		if(contexts.size()>0) {
+			Assert.assertTrue(contexts.size() <= limit);
+			
+			for(Context context : contexts) {
+				UUID uuid = context.getID();
+				Assert.assertFalse(uuids.contains(uuid));
+				uuids.add(uuid);
+				logger.info("Found {} with UUID {} and name {}", Context.NAME, uuid, context.getName());
+			}
+			
+			if(contexts.size()<limit) {
+				return;
+			}
+			
+			
+			int doubleLimit = limit*2;
+			
+			contexts = getAll(0, doubleLimit);
+			
+			Assert.assertTrue(contexts.size() <= doubleLimit);
+			
+			for(Context context : contexts) {
+				UUID uuid = context.getID();
+				logger.info("Checking if {} with UUID {} and name {} was contained in the previous queries", Context.NAME, uuid, context.getName());
+				Assert.assertTrue(uuids.contains(uuid));
+				logger.info("As expected got {} with UUID {} and name {}", Context.NAME, uuid, context.getName());
+			}
+		}
+		
+		contexts = getAll();
+		
+		Assert.assertTrue(contexts.size()>=uuids.size());
+		
+		for(Context context : contexts) {
+			UUID uuid = context.getID();
+			logger.info("No limit listing: Got {} with UUID {} and name {}", Context.NAME, uuid, context.getName());
+		}
+	}
 }

src/test/resources/logback-test.xml

@@ -14,6 +14,7 @@
   <logger name="org.gcube.informationsystem.types" level="INFO" />
   <logger name="org.gcube.informationsystem.resourceregistry.dbinitialization" level="INFO" />
   <logger name="org.gcube.informationsystem.utils.discovery" level="ERROR" />
+  <logger name="org.gcube.informationsystem.resourceregistry.contexts" level="INFO" />
   <logger name="org.gcube.informationsystem.resourceregistry.types" level="TRACE" />
   <logger name="org.gcube.informationsystem.resourceregistry.instances" level="TRACE" />