| /** |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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.metamodel.elasticsearch; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| import org.apache.metamodel.data.AbstractDataSet; |
| import org.apache.metamodel.data.DataSet; |
| import org.apache.metamodel.data.Row; |
| import org.apache.metamodel.elasticsearch.common.ElasticSearchUtils; |
| import org.apache.metamodel.query.SelectItem; |
| import org.elasticsearch.action.search.SearchResponse; |
| import org.elasticsearch.search.SearchHit; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * {@link DataSet} implementation for ElasticSearch |
| */ |
| public abstract class AbstractElasticSearchDataSet extends AbstractDataSet { |
| |
| private static final Logger logger = LoggerFactory.getLogger(AbstractElasticSearchDataSet.class); |
| |
| protected final AtomicBoolean _closed; |
| |
| protected SearchResponse _searchResponse; |
| protected SearchHit _currentHit; |
| protected int _hitIndex = 0; |
| |
| public AbstractElasticSearchDataSet(final SearchResponse searchResponse, final List<SelectItem> selectItems) { |
| super(selectItems); |
| _searchResponse = searchResponse; |
| _closed = new AtomicBoolean(false); |
| } |
| |
| @Override |
| public void close() { |
| super.close(); |
| boolean closeNow = _closed.compareAndSet(true, false); |
| if (closeNow) { |
| closeNow(); |
| } |
| } |
| |
| protected abstract void closeNow(); |
| |
| @Override |
| protected void finalize() throws Throwable { |
| super.finalize(); |
| if (!_closed.get()) { |
| logger.warn("finalize() invoked, but DataSet is not closed. Invoking close() on {}", this); |
| close(); |
| } |
| } |
| |
| @Override |
| public boolean next() { |
| final SearchHit[] hits = _searchResponse.getHits().getHits(); |
| if (hits.length == 0) { |
| // break condition for the scroll |
| _currentHit = null; |
| return false; |
| } |
| |
| if (_hitIndex < hits.length) { |
| // pick the next hit within this search response |
| _currentHit = hits[_hitIndex]; |
| _hitIndex++; |
| return true; |
| } |
| |
| final String scrollId = _searchResponse.getScrollId(); |
| if (scrollId == null) { |
| // this search response is not scrolleable - then it's the end. |
| _currentHit = null; |
| return false; |
| } |
| |
| // try to scroll to the next set of hits |
| try { |
| _searchResponse = scrollSearchResponse(scrollId); |
| } catch (IOException e) { |
| logger.warn("Failed to scroll to the next search response set.", e); |
| return false; |
| } |
| |
| // start over (recursively) |
| _hitIndex = 0; |
| return next(); |
| } |
| |
| protected abstract SearchResponse scrollSearchResponse(final String scrollId) throws IOException; |
| |
| @Override |
| public Row getRow() { |
| if (_currentHit == null) { |
| return null; |
| } |
| |
| final Map<String, Object> source = _currentHit.getSource(); |
| final String documentId = _currentHit.getId(); |
| return ElasticSearchUtils.createRow(source, documentId, getHeader()); |
| } |
| } |