Merge pull request #6597 from MishaDemianenko/3.0-iterables-iterators

Cleanup and brush Iterables and Iterators helpers

community/bolt/src/main/java/org/neo4j/bolt/v1/messaging/infrastructure/ValueNode.java

@@ -27,6 +27,7 @@
 import java.util.Map;
 
 import org.neo4j.bolt.v1.messaging.BoltIOException;
+import org.neo4j.bolt.v1.messaging.Neo4jPack;
 import org.neo4j.graphdb.Direction;
 import org.neo4j.graphdb.GraphDatabaseService;
 import org.neo4j.graphdb.Label;
@@ -35,7 +36,6 @@
 import org.neo4j.graphdb.RelationshipType;
 import org.neo4j.helpers.collection.Iterables;
 import org.neo4j.kernel.api.exceptions.Status;
-import org.neo4j.bolt.v1.messaging.Neo4jPack;
 
 public class ValueNode
         extends ValuePropertyContainer
@@ -48,7 +48,7 @@ public static void pack( Neo4jPack.Packer packer, Node node )
     {
         packer.packStructHeader( STRUCT_FIELD_COUNT, Neo4jPack.NODE );
         packer.pack( node.getId() );
-        Collection<Label> collectedLabels = Iterables.toList( node.getLabels() );
+        Collection<Label> collectedLabels = Iterables.asList( node.getLabels() );
         packer.packListHeader( collectedLabels.size() );
         for ( Label label : collectedLabels )
         {

community/bolt/src/test/java/org/neo4j/bolt/v1/docs/DocSerialization.java

@@ -153,7 +153,7 @@ else if ( value.equals( "FAILURE { \"code\": \"Neo.ClientError.Statement.Invalid
                                 (Map<String, Object>) args.get( 1 ) );
                         break;
                     case "RECORD":
-                        writer.handleRecordMessage( new ImmutableRecord( Iterables.toArray(
+                        writer.handleRecordMessage( new ImmutableRecord( Iterables.asArray(
                                 Object.class, (List<Object>) args.get( 0 ) ) ) );
                         break;
                     case "SUCCESS":

community/collections/src/main/java/org/neo4j/helpers/collection/FilterIterable.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2002-2016 "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.helpers.collection;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.function.Predicate;
+
+class FilterIterable<T> implements Iterable<T>
+{
+    private final Iterable<T> iterable;
+
+    private final Predicate<? super T> specification;
+
+    public FilterIterable( Iterable<T> iterable, Predicate<? super T> specification )
+    {
+        this.iterable = iterable;
+        this.specification = specification;
+    }
+
+    @Override
+    public Iterator<T> iterator()
+    {
+        return new FilterIterator<>( iterable.iterator(), specification );
+    }
+
+    static class FilterIterator<T> implements Iterator<T>
+    {
+        private final Iterator<T> iterator;
+
+        private final Predicate<? super T> specification;
+
+        private T currentValue;
+        boolean finished = false;
+        boolean nextConsumed = true;
+
+        public FilterIterator( Iterator<T> iterator, Predicate<? super T> specification )
+        {
+            this.specification = specification;
+            this.iterator = iterator;
+        }
+
+        public boolean moveToNextValid()
+        {
+            boolean found = false;
+            while ( !found && iterator.hasNext() )
+            {
+                T currentValue = iterator.next();
+                boolean satisfies = specification.test( currentValue );
+
+                if ( satisfies )
+                {
+                    found = true;
+                    this.currentValue = currentValue;
+                    nextConsumed = false;
+                }
+            }
+            if ( !found )
+            {
+                finished = true;
+            }
+            return found;
+        }
+
+        @Override
+        public T next()
+        {
+            if ( !nextConsumed )
+            {
+                nextConsumed = true;
+                return currentValue;
+            }
+            else
+            {
+                if ( !finished )
+                {
+                    if ( moveToNextValid() )
+                    {
+                        nextConsumed = true;
+                        return currentValue;
+                    }
+                }
+            }
+            throw new NoSuchElementException( "This iterator is exhausted." );
+        }
+
+        @Override
+        public boolean hasNext()
+        {
+            return !finished && (!nextConsumed || moveToNextValid());
+        }
+
+        @Override
+        public void remove()
+        {
+        }
+    }
+}