| package com.datatorrent.lib.algo; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.Context.OperatorContext; |
| import com.datatorrent.api.Operator.Unifier; |
| |
| /** |
| * This unifier is used by the LeastFrequentKey operator in order to merge the output of the "list" output port. |
| * <p></p> |
| * @displayName Emit Least Frequent Value |
| * @category Algorithmic |
| * @tags filter, count |
| * |
| * @since 0.3.3 |
| */ |
| public class LeastFrequentKeyArrayUnifier<K> implements Unifier<ArrayList<HashMap<K, Integer>>> |
| { |
| /** |
| * Key/Least value map. |
| */ |
| private HashMap<K, Integer> leastMap = new HashMap<K, Integer>(); |
| |
| /** |
| * The output port on which the least frequent tuple is emitted. |
| */ |
| public final transient DefaultOutputPort<HashMap<K, Integer>> mergedport = new DefaultOutputPort<HashMap<K, Integer>>(); |
| |
| @Override |
| public void beginWindow(long arg0) |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @Override |
| public void endWindow() |
| { |
| mergedport.emit(leastMap); |
| leastMap.clear(); |
| } |
| |
| @Override |
| public void setup(OperatorContext arg0) |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @Override |
| public void teardown() |
| { |
| // TODO Auto-generated method stub |
| |
| } |
| |
| @Override |
| public void process(ArrayList<HashMap<K, Integer>> tuples) |
| { |
| for (HashMap<K, Integer> tuple : tuples) { |
| for (Map.Entry<K, Integer> entry : tuple.entrySet()) { |
| Integer value = entry.getValue(); |
| if (leastMap.containsKey(entry.getKey())) { |
| if (leastMap.get(entry.getKey()) < value) { |
| value = leastMap.remove(entry.getKey()); |
| } else { |
| leastMap.remove(entry.getKey()); |
| } |
| } |
| leastMap.put(entry.getKey(), value); |
| } |
| } |
| } |
| |
| } |