| /* |
| * 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.solr.search; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.search.LeafCollector; |
| import org.apache.lucene.search.Collector; |
| import org.apache.lucene.search.FilterLeafCollector; |
| import org.apache.lucene.search.FilterCollector; |
| /** |
| * <p> |
| * A wrapper {@link Collector} that throws {@link EarlyTerminatingCollectorException}) |
| * once a specified maximum number of documents are collected. |
| * </p> |
| */ |
| public class EarlyTerminatingCollector extends FilterCollector { |
| |
| private final int maxDocsToCollect; |
| |
| private int numCollected = 0; |
| private int prevReaderCumulativeSize = 0; |
| private int currentReaderSize = 0; |
| |
| /** |
| * <p> |
| * Wraps a {@link Collector}, throwing {@link EarlyTerminatingCollectorException} |
| * once the specified maximum is reached. |
| * </p> |
| * @param delegate - the Collector to wrap. |
| * @param maxDocsToCollect - the maximum number of documents to Collect |
| * |
| */ |
| public EarlyTerminatingCollector(Collector delegate, int maxDocsToCollect) { |
| super(delegate); |
| assert 0 < maxDocsToCollect; |
| assert null != delegate; |
| |
| this.maxDocsToCollect = maxDocsToCollect; |
| } |
| |
| @Override |
| public LeafCollector getLeafCollector(LeafReaderContext context) |
| throws IOException { |
| prevReaderCumulativeSize += currentReaderSize; // not current any more |
| currentReaderSize = context.reader().maxDoc() - 1; |
| |
| return new FilterLeafCollector(super.getLeafCollector(context)) { |
| |
| @Override |
| public void collect(int doc) throws IOException { |
| super.collect(doc); |
| numCollected++; |
| if (maxDocsToCollect <= numCollected) { |
| throw new EarlyTerminatingCollectorException |
| (numCollected, prevReaderCumulativeSize + (doc + 1)); |
| } |
| } |
| |
| }; |
| } |
| |
| } |