Allow lists to contain NO_VALUE

community/values/src/main/java/org/neo4j/values/result/QueryResult.java

@@ -0,0 +1,152 @@
+/*
+ * Copyright (c) 2002-2017 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.values.result;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+import org.neo4j.graphdb.ExecutionPlanDescription;
+import org.neo4j.graphdb.Node;
+import org.neo4j.graphdb.Notification;
+import org.neo4j.graphdb.Path;
+import org.neo4j.graphdb.QueryExecutionType;
+import org.neo4j.graphdb.QueryStatistics;
+import org.neo4j.graphdb.Relationship;
+import org.neo4j.graphdb.Result;
+import org.neo4j.values.AnyValue;
+
+import static org.neo4j.helpers.Exceptions.withCause;
+
+public interface QueryResult
+{
+    String[] fieldNames();
+
+    <E extends Exception> void accept( QueryResultVisitor<E> visitor )
+            throws E;
+
+    interface QueryResultVisitor<E extends Exception>
+    {
+        boolean visit( Record row ) throws E;
+    }
+
+    interface Record
+    {
+        AnyValue[] fields();
+    }
+
+    QueryExecutionType getQueryExecutionType();
+
+    QueryStatistics getQueryStatistics();
+
+    ExecutionPlanDescription getExecutionPlanDescription();
+
+    Iterable<Notification> getNotifications();
+
+    Result asPublicResult();
+
+    void close();
+}
+
+abstract class IterableQueryResult implements QueryResult, Result
+{
+    private final Map<String,Integer> indexLookup;
+
+    IterableQueryResult()
+    {
+        String[] names = fieldNames();
+        indexLookup = new HashMap<>( names.length );
+        for ( int i = 0; i < names.length; i++ )
+        {
+            indexLookup.put( names[i], i );
+        }
+    }
+
+    @Override
+    public <VisitationException extends Exception> void accept( ResultVisitor<VisitationException> visitor )
+            throws VisitationException
+    {
+        accept( (QueryResultVisitor<VisitationException>) row -> visitor.visit( new ResultRow()
+        {
+            @Override
+            public Node getNode( String key )
+            {
+                return get( key, Node.class );
+            }
+
+            @Override
+            public Relationship getRelationship( String key )
+            {
+                return get( key, Relationship.class );
+            }
+
+            @Override
+            public Object get( String key )
+            {
+                return get( key, Object.class );
+            }
+
+            @Override
+            public String getString( String key )
+            {
+                return get( key, String.class );
+            }
+
+            @Override
+            public Number getNumber( String key )
+            {
+                return get( key, Number.class );
+            }
+
+            @Override
+            public Boolean getBoolean( String key )
+            {
+                return get( key, Boolean.class );
+            }
+
+            @Override
+            public Path getPath( String key )
+            {
+                return get( key, Path.class );
+            }
+
+            private <T> T get( String key, Class<T> type )
+            {
+                if ( !indexLookup.containsKey( key ) )
+                {
+                    throw new NoSuchElementException( "No such entry: " + key );
+                }
+                Integer index = indexLookup.get( key );
+
+                //TODO do this with a writer, this is wrong
+                Object value = row.fields()[index];
+                try
+                {
+                    return type.cast( value );
+                }
+                catch ( ClassCastException e )
+                {
+                    throw withCause( new NoSuchElementException(
+                            "Element '" + key + "' is not a " + type.getSimpleName() ), e );
+                }
+            }
+        } ) );
+    }
+}

community/values/src/main/java/org/neo4j/values/virtual/ArrayHelpers.java

@@ -75,11 +75,11 @@ static boolean isSortedSet( Value[] keys, Comparator<AnyValue> comparator )
         return true;
     }
 
-    static boolean hasNullOrNoValue( AnyValue[] values )
+    static boolean containsNull( AnyValue[] values )
     {
         for ( AnyValue value : values )
         {
-            if ( value == null || value == Values.NO_VALUE )
+            if ( value == null )
             {
                 return true;
             }

community/values/src/main/java/org/neo4j/values/virtual/ListValue.java

@@ -27,7 +27,7 @@
 import org.neo4j.values.SequenceValue;
 import org.neo4j.values.VirtualValue;
 
-import static org.neo4j.values.virtual.ArrayHelpers.hasNullOrNoValue;
+import static org.neo4j.values.virtual.ArrayHelpers.containsNull;
 
 final class ListValue extends VirtualValue implements SequenceValue
 {
@@ -36,7 +36,8 @@ final class ListValue extends VirtualValue implements SequenceValue
     ListValue( AnyValue[] values )
     {
         assert values != null;
-        assert !hasNullOrNoValue( values );
+        assert !containsNull( values );
+
         this.values = values;
     }