/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.util.iterator;
import java.util.Iterator;
/**
An empty iterator. The specialised versions of andThen() eliminate left operands
that are empty iterators from cascaded sequences.
*/
public class NullIterator<T> extends NiceIterator<T>
{
public static <T> NullIterator<T> instance()
{ return new NullIterator<>(); }
@SuppressWarnings("unchecked")
@Override public <X extends T> ExtendedIterator<T> andThen( Iterator<X> it )
{
return it instanceof ExtendedIterator
? (ExtendedIterator<T>) it
: super.andThen( it )
;
}
}