| /** |
| * 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.apex.malhar.lib.math; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| import org.apache.apex.malhar.lib.util.BaseNumberKeyValueOperator; |
| import org.apache.apex.malhar.lib.util.KeyValPair; |
| |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.DefaultOutputPort; |
| import com.datatorrent.api.StreamCodec; |
| |
| /** |
| * |
| * This operator emits minimum of all values sub-classed from Number for each key in KeyValPair at end of window. <p> |
| * <br> |
| * |
| * <b>Ports</b>:<br> |
| * <b>data</b>: expects KeyValPair<K,V extends Number><br> |
| * <b>min</b>: emits KeyValPair<K,V extends Number>, one entry per key<br> |
| * <br> |
| * <b>Properties</b>:<br> |
| * <b>inverse</b>: if set to true the key in the filter will block tuple<br> |
| * <b>filterBy</b>: List of keys to filter on<br> |
| * <br> |
| * @displayName Minimum Key Value |
| * @category Math |
| * @tags minimum, numeric, key value |
| * @since 0.3.2 |
| */ |
| public class MinKeyVal<K, V extends Number> extends BaseNumberKeyValueOperator<K, V> |
| { |
| /** |
| * Input port which takes a key vaue pair and updates the value for each key if there is a new min. |
| */ |
| public final transient DefaultInputPort<KeyValPair<K, V>> data = new DefaultInputPort<KeyValPair<K, V>>() |
| { |
| /** |
| * For each key, updates the hash if the new value is a new min. |
| */ |
| @Override |
| public void process(KeyValPair<K, V> tuple) |
| { |
| K key = tuple.getKey(); |
| V tval = tuple.getValue(); |
| if (!doprocessKey(key) || (tval == null)) { |
| return; |
| } |
| V val = mins.get(key); |
| if (val == null) { |
| mins.put(cloneKey(key), tval); |
| } else if (val.doubleValue() > tval.doubleValue()) { |
| mins.put(key, tval); |
| } |
| } |
| |
| /** |
| * Set StreamCodec used for partitioning. |
| */ |
| @Override |
| public StreamCodec<KeyValPair<K, V>> getStreamCodec() |
| { |
| return getKeyValPairStreamCodec(); |
| } |
| }; |
| |
| /** |
| * Min value output port. |
| */ |
| public final transient DefaultOutputPort<KeyValPair<K, V>> min = new DefaultOutputPort<KeyValPair<K, V>>(); |
| protected HashMap<K, V> mins = new HashMap<K, V>(); |
| |
| /** |
| * Emits all key,min value pairs. |
| * Clears internal data. Node only works in windowed mode. |
| */ |
| @SuppressWarnings({ "unchecked", "rawtypes" }) |
| @Override |
| public void endWindow() |
| { |
| if (!mins.isEmpty()) { |
| for (Map.Entry<K, V> e: mins.entrySet()) { |
| min.emit(new KeyValPair(e.getKey(), e.getValue())); |
| } |
| mins.clear(); |
| } |
| } |
| } |