Java tutorial
/* * Copyright (c) 2015, WSO2 Inc. (http://www.wso2.org) 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 org.wso2.devicemgt.raspberry.agent; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.impl.nio.client.HttpAsyncClients; import org.apache.log4j.Logger; import org.wso2.siddhi.core.SiddhiManager; import org.wso2.siddhi.core.event.Event; import org.wso2.siddhi.core.stream.input.InputHandler; import org.wso2.siddhi.core.stream.output.StreamCallback; import org.wso2.siddhi.core.util.EventPrinter; import org.apache.http.impl.nio.client.CloseableHttpAsyncClient; import org.apache.http.concurrent.FutureCallback; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.nio.charset.Charset; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Paths; import java.util.concurrent.CountDownLatch; import java.util.concurrent.Future; /** * This class reads the sonar reading and injects values * to the siddhiEngine for processing on a routine basis * also if the siddhiquery is updated the class takes * care of re-initializing same. */ public class SidhdhiQuery implements Runnable { private static final Logger log = Logger.getLogger(SidhdhiQuery.class); final AgentConstants constants = new AgentConstants(); //Bam data push client private static PushBamData pushBamData = new PushBamData(); private static SiddhiManager siddhiManager = new SiddhiManager(); public static PushBamData getPushBamData() { return pushBamData; } public static SiddhiManager getSiddhiManager() { return siddhiManager; } public static void setSiddhiManager(SiddhiManager siddhiManager) { SidhdhiQuery.siddhiManager = siddhiManager; } //keeps track of bulb status. The start status is assumed as off //TODO : pick up current bulb status from a API boolean isBulbOn = false; public void run() { //Initialize Push data client PushBamData pushdata = getPushBamData(); pushdata.initializeDataPublisher(); //Start the execution plan with pre-defined or previously persisted Siddhi query StartExecutionPlan startExecutionPlan = new StartExecutionPlan().invoke(); while (true) { //Check if there is new policy update available if (AgentInitializer.isUpdated()) { System.out.print("### Policy Update Detected!"); //Restart execution plan with new query restartSiddhi(); startExecutionPlan = new StartExecutionPlan().invoke(); } InputHandler inputHandler = startExecutionPlan.getInputHandler(); //Sending events to Siddhi try { //If sonar URL is present in the config file the program will read stats off the API //If not it will look for a file which is also configurable via a property String sonarUrl = constants.prop.getProperty("sonar.reading.url"); String sonarReading = null; if (sonarUrl != null) { sonarReading = readSonarData(sonarUrl); } if (sonarReading == null || sonarReading.equalsIgnoreCase("")) { sonarReading = readFile(constants.prop.getProperty("sonar.reading.file.path"), StandardCharsets.UTF_8); } log.info("Pushing data to CEP - Sonar : " + sonarReading.trim()); inputHandler.send(new Object[] { "FIRE_1", Double.parseDouble(sonarReading) }); Thread.sleep(Integer.parseInt(constants.prop.getProperty("read.interval"))); // executionPlanRuntime.shutdown(); } catch (InterruptedException e) { e.printStackTrace(); } } } /** * Re-Initialize SiddhiManager */ private void restartSiddhi() { siddhiManager.shutdown(); siddhiManager = new SiddhiManager(); } /** * Make http call to specified endpoint with events * @param inEvents * @param bulbEP * @param logText */ private void performHTTPCall(Event[] inEvents, String bulbEP, String logText) { if (inEvents != null && inEvents.length > 0) { EventPrinter.print(inEvents); String url = constants.prop.getProperty(bulbEP); CloseableHttpAsyncClient httpclient = null; httpclient = HttpAsyncClients.createDefault(); httpclient.start(); HttpGet request = new HttpGet(url); log.info("Bulb Status : " + logText); final CountDownLatch latch = new CountDownLatch(1); Future<HttpResponse> future = httpclient.execute(request, new FutureCallback<HttpResponse>() { @Override public void completed(HttpResponse httpResponse) { latch.countDown(); } @Override public void failed(Exception e) { latch.countDown(); } @Override public void cancelled() { latch.countDown(); } }); try { latch.await(); } catch (InterruptedException e) { e.printStackTrace(); } } } /** * Read content from a given file and return as a string * @param path * @param encoding * @return */ static String readFile(String path, Charset encoding) { byte[] encoded = new byte[0]; try { encoded = Files.readAllBytes(Paths.get(path)); } catch (IOException e) { log.error("Error reading Sidhdhi query from file."); } return new String(encoded, encoding); } /** * Read sonar data from API URL * @param sonarAPIUrl * @return */ private String readSonarData(String sonarAPIUrl) { HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(sonarAPIUrl); String responseStr = null; try { HttpResponse response = client.execute(request); log.debug("Response Code : " + response); InputStream input = response.getEntity().getContent(); BufferedReader br = new BufferedReader(new InputStreamReader(input, "UTF-8")); responseStr = String.valueOf(br.readLine()); br.close(); } catch (IOException e) { //log.error("Exception encountered while trying to make get request."); log.error("Error while reading sonar reading from file!"); return responseStr; } return responseStr; } /** * Initialize SiddhiExecution plan */ private class StartExecutionPlan { private InputHandler inputHandler; public InputHandler getInputHandler() { return inputHandler; } public StartExecutionPlan invoke() { String executionPlan; executionPlan = readFile(constants.prop.getProperty("execution.plan.file.location"), StandardCharsets.UTF_8); //Generating runtime siddhiManager.addExecutionPlan(executionPlan); siddhiManager.addCallback("bulbOnStream", new StreamCallback() { @Override public void receive(Event[] events) { System.out.println("Bulb on Event Fired!"); if (events.length > 0) { if (!isBulbOn) { performHTTPCall(events, "bulb.on.api.endpoint", "Bulb Switched on!"); System.out.println("#### Performed HTTP call! ON."); pushBamData.publishData(constants.prop.getProperty("device.id"), constants.prop.getProperty("device.type"), constants.prop.getProperty("device.user"), "BULB SWITCHED ON"); isBulbOn = true; } } } }); siddhiManager.addCallback("bulbOffStream", new StreamCallback() { @Override public void receive(Event[] inEvents) { System.out.println("Bulb off Event Fired"); if (isBulbOn) { performHTTPCall(inEvents, "bulb.off.api.endpoint", "Bulb Switched off!"); System.out.println("#### Performed HTTP call! OFF."); pushBamData.publishData(constants.prop.getProperty("device.id"), constants.prop.getProperty("device.type"), constants.prop.getProperty("device.user"), "BULB SWITCHED OFF"); isBulbOn = false; } } }); //Retrieving InputHandler to push events into Siddhi inputHandler = siddhiManager.getInputHandler("fireAlarmEventStream"); //Starting event processing System.out.println("Execution Plan Started!"); return this; } } }