| /* |
| * 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.client.solrj.io.ops; |
| |
| import java.io.IOException; |
| import java.io.Serializable; |
| import java.util.ArrayList; |
| import java.util.Comparator; |
| import java.util.LinkedList; |
| import java.util.List; |
| import java.util.Locale; |
| import java.util.Map; |
| import java.util.PriorityQueue; |
| import java.util.UUID; |
| |
| import org.apache.solr.client.solrj.io.Tuple; |
| import org.apache.solr.client.solrj.io.comp.FieldComparator; |
| import org.apache.solr.client.solrj.io.comp.StreamComparator; |
| import org.apache.solr.client.solrj.io.stream.expr.Explanation; |
| import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpression; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionNamedParameter; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionParameter; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue; |
| import org.apache.solr.client.solrj.io.stream.expr.StreamFactory; |
| |
| import static org.apache.solr.common.params.CommonParams.SORT; |
| |
| public class GroupOperation implements ReduceOperation { |
| |
| private static final long serialVersionUID = 1L; |
| private UUID operationNodeId = UUID.randomUUID(); |
| |
| private PriorityQueue<Tuple> priorityQueue; |
| @SuppressWarnings({"rawtypes"}) |
| private Comparator comp; |
| private StreamComparator streamComparator; |
| private int size; |
| |
| public GroupOperation(StreamExpression expression, StreamFactory factory) throws IOException { |
| |
| StreamExpressionNamedParameter nParam = factory.getNamedOperand(expression, "n"); |
| StreamExpressionNamedParameter sortExpression = factory.getNamedOperand(expression, SORT); |
| |
| StreamComparator streamComparator = factory.constructComparator(((StreamExpressionValue) sortExpression.getParameter()).getValue(), FieldComparator.class); |
| String nStr = ((StreamExpressionValue)nParam.getParameter()).getValue(); |
| int nInt = 0; |
| |
| try{ |
| nInt = Integer.parseInt(nStr); |
| if(nInt <= 0){ |
| throw new IOException(String.format(Locale.ROOT,"invalid expression %s - topN '%s' must be greater than 0.",expression, nStr)); |
| } |
| } catch(NumberFormatException e) { |
| throw new IOException(String.format(Locale.ROOT,"invalid expression %s - topN '%s' is not a valid integer.",expression, nStr)); |
| } |
| |
| init(streamComparator, nInt); |
| } |
| |
| public GroupOperation(StreamComparator streamComparator, int size) { |
| init(streamComparator, size); |
| } |
| |
| @SuppressWarnings({"unchecked", "rawtypes"}) |
| private void init(StreamComparator streamComparator, int size) { |
| this.size = size; |
| this.streamComparator = streamComparator; |
| this.comp = new ReverseComp(streamComparator); |
| this.priorityQueue = new PriorityQueue(size, this.comp); |
| } |
| |
| public StreamExpressionParameter toExpression(StreamFactory factory) throws IOException { |
| StreamExpression expression = new StreamExpression(factory.getFunctionName(this.getClass())); |
| // n |
| expression.addParameter(new StreamExpressionNamedParameter("n", Integer.toString(size))); |
| |
| // sort |
| expression.addParameter(new StreamExpressionNamedParameter(SORT, streamComparator.toExpression(factory))); |
| return expression; |
| } |
| |
| @Override |
| public Explanation toExplanation(StreamFactory factory) throws IOException { |
| return new Explanation(operationNodeId.toString()) |
| .withExpressionType(ExpressionType.OPERATION) |
| .withFunctionName(factory.getFunctionName(getClass())) |
| .withImplementingClass(getClass().getName()) |
| .withExpression(toExpression(factory).toString()) |
| .withHelpers(new Explanation[]{ |
| streamComparator.toExplanation(factory) |
| }); |
| } |
| |
| @SuppressWarnings({"unchecked"}) |
| public Tuple reduce() { |
| @SuppressWarnings({"rawtypes"}) |
| LinkedList ll = new LinkedList(); |
| while(priorityQueue.size() > 0) { |
| ll.addFirst(priorityQueue.poll().getFields()); |
| //This will clear priority queue and so it will be ready for the next group. |
| } |
| |
| @SuppressWarnings({"rawtypes"}) |
| List<Map> list = new ArrayList<>(ll); |
| @SuppressWarnings({"rawtypes"}) |
| Map groupHead = list.get(0); |
| Tuple tuple = new Tuple(groupHead); |
| tuple.put("group", list); |
| return tuple; |
| } |
| |
| public void operate(Tuple tuple) { |
| if(priorityQueue.size() >= size) { |
| Tuple peek = priorityQueue.peek(); |
| if(streamComparator.compare(tuple, peek) < 0) { |
| priorityQueue.poll(); |
| priorityQueue.add(tuple); |
| } |
| } else { |
| priorityQueue.add(tuple); |
| } |
| } |
| |
| static class ReverseComp implements Comparator<Tuple>, Serializable { |
| private StreamComparator comp; |
| |
| public ReverseComp(StreamComparator comp) { |
| this.comp = comp; |
| } |
| |
| public int compare(Tuple t1, Tuple t2) { |
| // Couldn't this be comp.compare(t2,t1) ? |
| return comp.compare(t1, t2)*(-1); |
| } |
| } |
| } |