Implementing projection

src/main/java/org/gcube/informationsystem/resourceregistry/queries/json/base/JsonQueryERElement.java

@@ -6,6 +6,8 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
+import javax.ws.rs.InternalServerErrorException;
+
 import org.gcube.com.fasterxml.jackson.databind.JsonNode;
 import org.gcube.com.fasterxml.jackson.databind.ObjectMapper;
 import org.gcube.com.fasterxml.jackson.databind.node.ArrayNode;
@@ -20,6 +22,7 @@ import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaE
 import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaNotFoundException;
 import org.gcube.informationsystem.resourceregistry.queries.operators.ConditionalOperator;
 import org.gcube.informationsystem.resourceregistry.queries.operators.LogicalOperator;
+import org.gcube.informationsystem.resourceregistry.queries.operators.ProjectionOperator;
 import org.gcube.informationsystem.resourceregistry.types.TypesCache;
 import org.gcube.informationsystem.utils.TypeUtility;
 import org.slf4j.Logger;
@@ -113,6 +116,8 @@ public abstract class JsonQueryERElement {
 		this.caller = null;
 		this.breadcrumb = new ArrayList<>();
 		this.position = 0;
+		this.alias = null;
+		this.fieldsToEmit = new ArrayList<>();
 		
 		
 		this.fieldNamesToRemove = new HashSet<>();
@@ -149,9 +154,13 @@ public abstract class JsonQueryERElement {
 	}
 
 	public void setProjection(boolean projection) {
+		if(!projection) {
+			throw new InternalServerErrorException("Projection can only be set to true from code. This is a server side bug. Please contact the administrator.");
+		}
 		this.projection = projection;
-		if(projection && !entryPoint) {
+		if(!entryPoint) {
-			breadcrumb.get(0).setEntryPoint(projection);
+			// Set the projection in the parent
+			breadcrumb.get(breadcrumb.size()-2).setProjection(projection);
 		}
 	}
 
@@ -205,12 +214,11 @@ public abstract class JsonQueryERElement {
 	 * @param fieldToEmit
 	 */
 	protected void addFieldToEmit(String fieldToEmit) {
-		if(entryPoint) {
 		fieldsToEmit.add(fieldToEmit);
-			logger.trace("The field to emit ({}) has been added to entry point, i.e. {} with alias {}", fieldToEmit, this.type, this.alias);
+		logger.trace("The field to emit ({}) has been added to {} with alias {}", fieldToEmit, this.type, this.alias);
-		}else {
+		if(!entryPoint) {
-			logger.trace("The field to emit ({}) will be added to entry point", fieldToEmit);
+			logger.trace("The field to emit ({}) will be added to the parent too", fieldToEmit);
-			breadcrumb.get(0).addFieldToEmit(fieldToEmit);
+			breadcrumb.get(breadcrumb.size()-2).addFieldToEmit(fieldToEmit);
 		}
 	}
 	
@@ -288,6 +296,25 @@ public abstract class JsonQueryERElement {
 	}
 	
 	protected StringBuffer evaluateNode(JsonNode jsonNode, String fieldName, String fieldNamePrefix) throws InvalidQueryException {
+		
+		if(ProjectionOperator.getOperators().contains(fieldName)) {
+			setProjection(true);
+			Iterator<String> iterator = jsonNode.fieldNames();
+			while(iterator.hasNext()) {
+				String fieldNameToEmit = iterator.next();
+				String nameOfFieldToEmit = jsonNode.get(fieldNameToEmit).asText();
+				StringBuffer b = new StringBuffer();
+				b.append(getAlias(true));
+				b.append(".");
+				b.append(fieldNameToEmit);
+				b.append(" AS ");
+				b.append(nameOfFieldToEmit);
+				addFieldToEmit(b.toString());
+			}
+			return null;
+		}
+		
+		
 		StringBuffer stringBuffer = new StringBuffer();
 		
 		if(LogicalOperator.getOperators().contains(fieldName)) {
@@ -441,7 +468,7 @@ public abstract class JsonQueryERElement {
 		List<JsonQueryERElement> childrenBreadcrumb = getChildrenBreadcrumb();
 		
 		if(entryPoint) {
-			alias = getAlias();
+			getAlias(true);
 		}
 		
 		StringBuffer buffer = getSpecificMatchQuery(childrenBreadcrumb);

src/main/java/org/gcube/informationsystem/resourceregistry/queries/json/base/entities/JsonQueryFacet.java

@@ -95,7 +95,7 @@ public class JsonQueryFacet extends JsonQueryEntity {
 	protected StringBuffer getSpecificMatchQuery(List<JsonQueryERElement> childrenBreadcrumb)
 			throws SchemaException, ResourceRegistryException {
 		// TODO Auto-generated method stub
-		return null;
+		return new StringBuffer();
 	}
 	
 }

src/main/java/org/gcube/informationsystem/resourceregistry/queries/json/base/entities/JsonQueryResource.java

@@ -123,7 +123,7 @@ public class JsonQueryResource extends JsonQueryEntity {
 		StringBuffer buffer = new StringBuffer();		
 		
 		if(!entryPoint) {
-			buffer.append("\n\t");
+			buffer.append("\n\t.");
 			buffer.append(direction.name().toLowerCase());
 			buffer.append("V('");
 			buffer.append(type);
@@ -160,13 +160,14 @@ public class JsonQueryResource extends JsonQueryEntity {
 				buffer = jsonQueryIsRelatedTo.createMatchQuery(buffer);
 				
 				if(traverseBack) {
-					buffer.append(jsonQueryIsRelatedTo.getDirection().opposite().name().toLowerCase());
+					buffer.append("\n\t.");
+					buffer.append(jsonQueryIsRelatedTo.getDirection().name().toLowerCase());
 					buffer.append("V('");
 					buffer.append(type);
 					buffer.append("') ");
-					if(alias!=null || entryPoint) {
+					if(getAlias()!=null || entryPoint) {
 						buffer.append("{ where: ($matched.");
-						buffer.append(alias);
+						buffer.append(getAlias());
 						buffer.append(" == $currentMatch)}\n");
 					}
 				}
@@ -194,13 +195,14 @@ public class JsonQueryResource extends JsonQueryEntity {
 				buffer = jsonQueryConsistsOf.createMatchQuery(buffer);
 				
 				if(traverseBack) {
-					buffer.append(jsonQueryConsistsOf.getDirection().opposite().name().toLowerCase());
+					buffer.append("\n\t.");
+					buffer.append(jsonQueryConsistsOf.getDirection().name().toLowerCase());
 					buffer.append("V('");
 					buffer.append(type);
 					buffer.append("') ");
-					if(alias!=null || entryPoint) {
+					if(getAlias()!=null || entryPoint) {
 						buffer.append("{ where: ($matched.");
-						buffer.append(alias);
+						buffer.append(getAlias());
 						buffer.append(" == $currentMatch)}\n");
 					}
 				}
@@ -210,5 +212,4 @@ public class JsonQueryResource extends JsonQueryEntity {
 		return buffer;
 	}
 	
-	
 }

src/main/java/org/gcube/informationsystem/resourceregistry/queries/json/base/relations/JsonQueryConsistsOf.java

@@ -167,14 +167,20 @@ public class JsonQueryConsistsOf extends JsonQueryRelation {
 			buffer.append(direction.name().toLowerCase());		
 			buffer.append("E('");
 			buffer.append(type);
-			buffer.append("'");
+			buffer.append("')");
 			
 			if(size>0) {
 				alias = getAlias(true);
 				buffer.append("{ where: ($matched.");
 				buffer.append(alias);
 				buffer.append(" == $currentMatch)");
-				buffer.append(addConstraints(jsonNode, null, alias));
+				
+				StringBuffer sb = addConstraints(jsonNode, null, alias);
+				if(sb!=null && sb.length()>0) {
+					buffer.append(" AND ");
+					buffer.append(sb);
+				}
+				
 				buffer.append("}\n");
 			}
 				
@@ -187,7 +193,7 @@ public class JsonQueryConsistsOf extends JsonQueryRelation {
 			buffer.append(direction.opposite().name().toLowerCase());		
 			buffer.append("E('");
 			buffer.append(type);
-			buffer.append("'");
+			buffer.append("')");
 		}
 		
 		return buffer;

src/main/java/org/gcube/informationsystem/resourceregistry/queries/operators/ProjectionOperator.java

@@ -0,0 +1,53 @@
+package org.gcube.informationsystem.resourceregistry.queries.operators;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * @author Luca Frosini (ISTI - CNR)
+ * See https://www.orientdb.com/docs/3.0.x/sql/SQL-Where.html
+ */
+public enum ProjectionOperator {
+
+	EMIT("_emit", "");
+	
+	protected final String operator;
+	protected final String description;
+	
+	private ProjectionOperator(String operator, String description) {
+		this.operator = operator;
+		this.description = description;
+	}
+	
+	public String getOperator() {
+		return operator;
+	}
+	
+	public String getDescription() {
+		return description;
+	}
+
+	private static Set<String> operators;
+	private static Map<String,ProjectionOperator> operatorByKey;
+	
+	static {
+		ProjectionOperator.operators = new HashSet<>();
+		ProjectionOperator.operatorByKey = new HashMap<>();
+		
+		for(ProjectionOperator po : ProjectionOperator.values()) {
+			ProjectionOperator.operators.add(po.getOperator());
+			ProjectionOperator.operatorByKey.put(po.getOperator(), po);
+		}
+	}
+	
+	public static Set<String> getOperators() {
+		return ProjectionOperator.operators;
+	}
+	
+	public static ProjectionOperator getQueryLogicalOperator(String key) {
+		return operatorByKey.get(key);
+	}
+	
+}

src/test/java/org/gcube/informationsystem/resourceregistry/queries/JsonQueryTest.java

@@ -35,6 +35,13 @@ public class JsonQueryTest extends ContextTest {
 		return new File(resourcesDirectory, "queries");
 	}
 	
+	public File getProjectionQueriesDirectory() throws Exception {
+		URL logbackFileURL = JsonQueryTest.class.getClassLoader().getResource("logback-test.xml");
+		File logbackFile = new File(logbackFileURL.toURI());
+		File resourcesDirectory = logbackFile.getParentFile();
+		return new File(resourcesDirectory, "projection-queries");
+	}
+	
 	@Test
 	public void testJsonQueries() throws Exception {
 		ContextTest.setContextByName(DEVVRE);
@@ -191,8 +198,8 @@ public class JsonQueryTest extends ContextTest {
 	
 	@Test
 	public void testCreateMatchQuery() throws Exception {
-		File queriesDirectory = getQueriesDirectory();
+		File queriesDirectory = getProjectionQueriesDirectory();
-		File jsonQueryFile = new File(queriesDirectory, "query6.json");
+		File jsonQueryFile = new File(queriesDirectory, "EService-query.json");
 		ObjectMapper objectMapper = new ObjectMapper();
 		JsonNode jsonNode = objectMapper.readTree(jsonQueryFile);
 		logger.info("Going to test the following JSON query {}", jsonNode.toString());

src/test/resources/projection-queries/EService-query.json

@@ -1,5 +1,5 @@
 {
-	"_projection" : {
+
 		"type": "EService",
 		"_emit" : { 
 			"id" : "id" 
@@ -45,5 +45,5 @@
 				}
 			}
 		]
-	}
+	
 }