| /** |
| * 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.util; |
| |
| import java.util.Map; |
| |
| import javax.validation.constraints.Min; |
| |
| import com.datatorrent.api.DefaultInputPort; |
| import com.datatorrent.api.StreamCodec; |
| |
| /** |
| * This is the base implementation for the Top N sorting operators. |
| * A concrete operator should be created from this skeleton implementation. |
| * <p> |
| * Users need to provide processTuple, beginWindow, and endWindow to implement TopN operator |
| * This is an end of window module. At the end of window all data is flushed. Thus the data set is windowed and no history is kept of previous windows<br> |
| * </p> |
| * <p> |
| * <b>Ports</b>:<br> |
| * <b>data</b>: expects HashMap<K,V><br> |
| * <b>top</b>: emits HashMap<K,ArrayList<V>><br> |
| * <br> |
| * <b>Properties</b>: |
| * <b>N</b>: The number of top values to be emitted per key<br> |
| * <br> |
| * <b>Specific compile time checks are</b>:<br> |
| * N: Has to be an integer<br> |
| * <br> |
| * <b>Specific run time checks are</b>: None<br> |
| * <br> |
| * <b>Benchmark</b>: Not done as this is an abstract operator<br> |
| * </p> |
| * @displayName Abstract Base N Map |
| * @category Algorithmic |
| * @tags rank, key value |
| * @since 0.3.2 |
| */ |
| public abstract class AbstractBaseNOperatorMap<K,V> extends BaseKeyValueOperator<K,V> |
| { |
| /** |
| * This is the input port that receives key value pairs. |
| */ |
| public final transient DefaultInputPort<Map<K,V>> data = new DefaultInputPort<Map<K,V>>() |
| { |
| @Override |
| public void process(Map<K,V> tuple) |
| { |
| processTuple(tuple); |
| } |
| |
| @Override |
| public StreamCodec<Map<K, V>> getStreamCodec() |
| { |
| StreamCodec<Map<K, V>> streamCodec = AbstractBaseNOperatorMap.this.getStreamCodec(); |
| if (streamCodec == null) { |
| return super.getStreamCodec(); |
| } else { |
| return streamCodec; |
| } |
| } |
| |
| |
| }; |
| @Min(1) |
| int n = 1; |
| |
| /** |
| * Implementations should specify exactly how tuples should be processed |
| * |
| * @param tuple |
| */ |
| public abstract void processTuple(Map<K,V> tuple); |
| |
| /** |
| * 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; |
| } |
| |
| /* |
| * Provides ability for implemented operators to provide their own stream codec |
| */ |
| protected StreamCodec<Map<K, V>> getStreamCodec() |
| { |
| return null; |
| } |
| } |