| /** |
| * 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 com.datatorrent.lib.algo; |
| |
| import java.util.ArrayList; |
| |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Operator; |
| import com.datatorrent.api.Operator.Unifier; |
| import com.datatorrent.api.annotation.OperatorAnnotation; |
| |
| /** |
| * This is a base class implementation of a unifier which merges sorted lists of tuples. |
| * The operator takes sorted lists as input tuples each window. |
| * At the end of each application window input tuples are merged into one large sorted list and emitted. |
| * Subclasses must implement the comparison method used for sorting. |
| * <p> |
| * Incoming sorted list is merged into already existing sorted list. The input list is expected to be sorted. <b> |
| * At the end of the window, merged sorted list is emitted on sort output port. <br> |
| * <br> |
| * <b>Notes : </b> <br> |
| * Get unifier instance must return instance of sub class itself, since merge operator |
| * id unifier on output port. <br> |
| * <br> |
| * <b>StateFull : Yes</b>, Sorted listed are merged over application window can be > 1. <br> |
| * <b>Partitions : Yes</b>, Operator itself is used as unfier on output port. |
| * <br> |
| * <b>Ports</b>:<br> |
| * <b>data</b>: expects ArrayList<K><br> |
| * <b>sort</b>: emits ArrayList<K><br> |
| * <br> |
| * <b>Abstract Methods: </b><br> |
| * 1. compare : K type value compare criteria for sort. |
| * 2. getUnifierInstance : Get unifier operator instance for output port, (must return self instance). |
| * |
| * @displayName Merge Sorted Lists (Generic) |
| * @category Algorithmic |
| * @tags rank |
| * </p> |
| * |
| * @since 0.3.3 |
| * @deprecated |
| */ |
| @Deprecated |
| @OperatorAnnotation(partitionable = true) |
| public abstract class MergeSort<K> implements Operator, Unifier<ArrayList<K>> |
| { |
| /** |
| * Sorted merged list. |
| */ |
| private ArrayList<K> mergedList = null; |
| |
| /** |
| * The input port which receives lists to be merged and sorted. |
| */ |
| public final transient DefaultInputPort<ArrayList<K>> data = new DefaultInputPort<ArrayList<K>>() |
| { |
| /** |
| * Merge incoming tuple. |
| */ |
| @Override |
| public void process(ArrayList<K> tuple) |
| { |
| mergedList = processMergeList(mergedList, tuple); |
| } |
| }; |
| |
| /** |
| * The output port which emits merged and sorted lists. |
| */ |
| public final transient DefaultOutputPort<ArrayList<K>> sort = new DefaultOutputPort<ArrayList<K>>() |
| { |
| @Override |
| public Unifier<ArrayList<K>> getUnifier() |
| { |
| return getUnifierInstance(); |
| } |
| }; |
| |
| @Override |
| public void setup(OperatorContext context) |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @Override |
| public void teardown() |
| { |
| // TODO Auto-generated method stub |
| } |
| |
| @Override |
| public void beginWindow(long windowId) |
| { |
| mergedList = null; |
| } |
| |
| @Override |
| public void endWindow() |
| { |
| sort.emit(mergedList); |
| mergedList = null; |
| } |
| |
| /** |
| * Sorted parameter list are merged into sorted merged output list. |
| * |
| * @param list1 sorted list aggregated by operator |
| * @param list2 Input port sorted list to be merged. |
| * @return sorted merged output list. |
| */ |
| protected ArrayList<K> processMergeList(ArrayList<K> list1, |
| ArrayList<K> list2) |
| { |
| // null lists |
| if (list1 == null) { |
| return list2; |
| } |
| if (list2 == null) { |
| return list1; |
| } |
| |
| // Create output list |
| ArrayList<K> result = new ArrayList<K>(); |
| int index1 = 0; |
| int index2 = 0; |
| while (true) { |
| |
| // list1 is exhausted |
| if (index1 == list1.size()) { |
| while (index2 < list2.size()) { |
| result.add(list2.get(index2++)); |
| } |
| break; |
| } |
| |
| // list2 is exhausted |
| if (index2 == list2.size()) { |
| while (index1 < list1.size()) { |
| result.add(list1.get(index1++)); |
| } |
| break; |
| } |
| |
| // compare values |
| K val1 = list1.get(index1++); |
| K val2 = list2.get(index2++); |
| K[] vals = compare(val1, val2); |
| result.add(vals[0]); |
| if (vals[1] != null) { |
| result.add(vals[1]); |
| } |
| } |
| |
| // done |
| return result; |
| } |
| |
| /** |
| * Unifier process function implementation. |
| */ |
| @Override |
| public void process(ArrayList<K> tuple) |
| { |
| mergedList = processMergeList(mergedList, tuple); |
| } |
| |
| /** |
| * abstract sort function to be implemented by sub class. |
| */ |
| public abstract K[] compare(K val1, K val2); |
| |
| /** |
| * Get output port unifier instance, sub class should return new instance of itself. |
| */ |
| public abstract Unifier<ArrayList<K>> getUnifierInstance(); |
| } |