| /* |
| * 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.phoenix.iterate; |
| |
| import java.sql.SQLException; |
| import java.util.List; |
| |
| import org.apache.phoenix.schema.tuple.Tuple; |
| |
| |
| /** |
| * |
| * Interface for iterating through results returned from a scan, adding the |
| * ability to peek at the next result. |
| * |
| * |
| * @since 0.1 |
| */ |
| public interface PeekingResultIterator extends ResultIterator { |
| public static final PeekingResultIterator EMPTY_ITERATOR = new PeekingResultIterator() { |
| |
| @Override |
| public Tuple next() throws SQLException { |
| return null; |
| } |
| |
| @Override |
| public Tuple peek() { |
| return null; |
| } |
| |
| @Override |
| public void close() throws SQLException { |
| } |
| |
| @Override |
| public void explain(List<String> planSteps) { |
| } |
| }; |
| |
| /** |
| * Returns the next result without advancing the iterator |
| * @throws SQLException |
| */ |
| public Tuple peek() throws SQLException; |
| } |