Java tutorial
/** * 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.demos.yahoofinance; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.List; import javax.validation.constraints.NotNull; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.cookie.CookiePolicy; import org.apache.commons.httpclient.methods.GetMethod; import org.apache.commons.httpclient.params.DefaultHttpParams; import org.apache.hadoop.util.StringUtils; import com.datatorrent.api.Context.OperatorContext; import com.datatorrent.api.DefaultOutputPort; import com.datatorrent.api.InputOperator; import com.datatorrent.api.annotation.OutputPortFieldAnnotation; import com.datatorrent.lib.util.KeyValPair; import au.com.bytecode.opencsv.CSVReader; /** * This operator sends price, volume and time into separate ports and calculates incremental volume. * * @since 0.3.2 */ public class StockTickInput implements InputOperator { private static final Logger logger = LoggerFactory.getLogger(StockTickInput.class); /** * Timeout interval for reading from server. 0 or negative indicates no timeout. */ public int readIntervalMillis = 500; /** * The URL of the web service resource for the POST request. */ private String url; private String[] symbols; @NotNull private String tickers; private transient HttpClient client; private transient GetMethod method; private HashMap<String, Long> lastVolume = new HashMap<String, Long>(); private boolean outputEvenIfZeroVolume = false; /** * The output port to emit price. */ @OutputPortFieldAnnotation(optional = true) public final transient DefaultOutputPort<KeyValPair<String, Double>> price = new DefaultOutputPort<KeyValPair<String, Double>>(); /** * The output port to emit incremental volume. */ @OutputPortFieldAnnotation(optional = true) public final transient DefaultOutputPort<KeyValPair<String, Long>> volume = new DefaultOutputPort<KeyValPair<String, Long>>(); /** * The output port to emit last traded time. */ @OutputPortFieldAnnotation(optional = true) public final transient DefaultOutputPort<KeyValPair<String, String>> time = new DefaultOutputPort<KeyValPair<String, String>>(); /** * Prepare URL from symbols and parameters. URL will be something like: http://download.finance.yahoo.com/d/quotes.csv?s=IBM,GOOG,AAPL,YHOO&f=sl1vt1 * * @return the URL */ private String prepareURL() { String str = "http://download.finance.yahoo.com/d/quotes.csv?s="; for (int i = 0; i < symbols.length; i++) { if (i != 0) { str += ","; } str += symbols[i]; } str += "&f=sl1vt1&e=.csv"; return str; } @Override public void setup(OperatorContext context) { url = prepareURL(); client = new HttpClient(); method = new GetMethod(url); DefaultHttpParams.getDefaultParams().setParameter("http.protocol.cookie-policy", CookiePolicy.BROWSER_COMPATIBILITY); } @Override public void teardown() { } @Override public void emitTuples() { try { int statusCode = client.executeMethod(method); if (statusCode != HttpStatus.SC_OK) { logger.error("Method failed: " + method.getStatusLine()); } else { InputStream istream = method.getResponseBodyAsStream(); // Process response InputStreamReader isr = new InputStreamReader(istream); CSVReader reader = new CSVReader(isr); List<String[]> myEntries = reader.readAll(); for (String[] stringArr : myEntries) { ArrayList<String> tuple = new ArrayList<String>(Arrays.asList(stringArr)); if (tuple.size() != 4) { return; } // input csv is <Symbol>,<Price>,<Volume>,<Time> String symbol = tuple.get(0); double currentPrice = Double.valueOf(tuple.get(1)); long currentVolume = Long.valueOf(tuple.get(2)); String timeStamp = tuple.get(3); long vol = currentVolume; // Sends total volume in first tick, and incremental volume afterwards. if (lastVolume.containsKey(symbol)) { vol -= lastVolume.get(symbol); } if (vol > 0 || outputEvenIfZeroVolume) { price.emit(new KeyValPair<String, Double>(symbol, currentPrice)); volume.emit(new KeyValPair<String, Long>(symbol, vol)); time.emit(new KeyValPair<String, String>(symbol, timeStamp)); lastVolume.put(symbol, currentVolume); } } } Thread.sleep(readIntervalMillis); } catch (InterruptedException ex) { logger.debug(ex.toString()); } catch (IOException ex) { logger.debug(ex.toString()); } } @Override public void beginWindow(long windowId) { } @Override public void endWindow() { } public void setOutputEvenIfZeroVolume(boolean outputEvenIfZeroVolume) { this.outputEvenIfZeroVolume = outputEvenIfZeroVolume; } public void setTickers(String tickers) { this.tickers = tickers; symbols = StringUtils.split(tickers, ','); } public String getTickers() { return tickers; } }