| /* |
| * Copyright (c) 2013 DataTorrent, Inc. ALL Rights Reserved. |
| * |
| * Licensed 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 java.util.HashMap; |
| import java.util.Map; |
| |
| import javax.validation.constraints.Min; |
| |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.Operator.Unifier; |
| import com.datatorrent.lib.util.TopNSort; |
| |
| /** |
| * This unifier takes an input stream of key value pairs is ordered by key, |
| * and the bottom N of the ordered tuples per key are emitted on port "bottom" at the end of window. |
| * <p></p> |
| * @displayName Bottom N Unifier |
| * @category Algorithmic |
| * @tags filter, rank, key value |
| * |
| * @since 0.3.3 |
| */ |
| public class BottomNUnifier<K, V> implements Unifier<HashMap<K, ArrayList<V>>> |
| { |
| /** |
| * Merged tuples map. |
| */ |
| protected HashMap<K, TopNSort<V>> kmap = new HashMap<K, TopNSort<V>>(); |
| |
| /** |
| * set n value. |
| */ |
| @Min(1) |
| int n = 1; |
| |
| /** |
| * The output port on which the bottom N tuples per key are emitted. |
| */ |
| public final transient DefaultOutputPort<HashMap<K, ArrayList<V>>> mergedport = new DefaultOutputPort<HashMap<K, ArrayList<V>>>(); |
| |
| @Override |
| public void beginWindow(long arg0) |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| |
| @Override |
| public void endWindow() |
| { |
| for (Map.Entry<K, TopNSort<V>> e : kmap.entrySet()) { |
| HashMap<K, ArrayList<V>> tuple = new HashMap<K, ArrayList<V>>(1); |
| tuple.put(e.getKey(), (ArrayList<V>)e.getValue().getTopN(getN())); |
| mergedport.emit(tuple); |
| } |
| kmap.clear(); |
| } |
| |
| @Override |
| public void setup(OperatorContext arg0) |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @Override |
| public void teardown() |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @SuppressWarnings({ "rawtypes", "unchecked" }) |
| @Override |
| public void process(HashMap<K, ArrayList<V>> tuple) |
| { |
| for (Map.Entry<K, ArrayList<V>> e : tuple.entrySet()) { |
| TopNSort pqueue = kmap.get(e.getKey()); |
| ArrayList<V> values = e.getValue(); |
| if (pqueue == null) { |
| pqueue = new TopNSort<V>(5, values.size(), false); |
| kmap.put(e.getKey(), pqueue); |
| for (int i = (values.size()-1); i >= 0; i--) { |
| pqueue.offer(values.get(i)); |
| } |
| } else { |
| for (int i = (values.size()-1); i >= 0; i--) { |
| pqueue.offer(values.get(i)); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Sets value of N (depth) |
| * |
| * @param val |
| */ |
| public void setN(int val) |
| { |
| n = val; |
| } |
| |
| /** |
| * getter function for N |
| * |
| * @return n |
| */ |
| @Min(1) |
| public int getN() |
| { |
| return n; |
| } |
| } |