001package com.pi4j.io.serial.impl; 002 003/* 004 * #%L 005 * ********************************************************************** 006 * ORGANIZATION : Pi4J 007 * PROJECT : Pi4J :: Java Library (Core) 008 * FILENAME : SerialDataMonitorThread.java 009 * 010 * This file is part of the Pi4J project. More information about 011 * this project can be found here: http://www.pi4j.com/ 012 * ********************************************************************** 013 * %% 014 * Copyright (C) 2012 - 2013 Pi4J 015 * %% 016 * Licensed under the Apache License, Version 2.0 (the "License"); 017 * you may not use this file except in compliance with the License. 018 * You may obtain a copy of the License at 019 * 020 * http://www.apache.org/licenses/LICENSE-2.0 021 * 022 * Unless required by applicable law or agreed to in writing, software 023 * distributed under the License is distributed on an "AS IS" BASIS, 024 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 025 * See the License for the specific language governing permissions and 026 * limitations under the License. 027 * #L% 028 */ 029 030 031import java.util.List; 032import java.util.concurrent.CopyOnWriteArrayList; 033 034import com.pi4j.io.serial.Serial; 035import com.pi4j.io.serial.SerialDataEvent; 036import com.pi4j.io.serial.SerialDataListener; 037 038/** 039 * <p> 040 * This implementation class implements the 'Serial' monitoring thread to poll the serial received 041 * buffer and notify registered event listeners when data is available. 042 * </p> 043 * 044 * <p> 045 * Before using the Pi4J library, you need to ensure that the Java VM in configured with access to 046 * the following system libraries: 047 * <ul> 048 * <li>pi4j</li> 049 * <li>wiringPi</li> 050 * </ul> 051 * <blockquote> This library depends on the wiringPi native system library.</br> (developed by 052 * Gordon Henderson @ <a href="https://projects.drogon.net/">https://projects.drogon.net/</a>) 053 * </blockquote> 054 * </p> 055 * 056 * @see #Serial 057 * @see #SerialDataEvent 058 * @see #SerialDataListener 059 * @see #SerialFactory 060 * 061 * @see <a href="http://www.pi4j.com/">http://www.pi4j.com/</a> 062 * @author Robert Savage (<a 063 * href="http://www.savagehomeautomation.com">http://www.savagehomeautomation.com</a>) 064 */ 065public class SerialDataMonitorThread extends Thread { 066 067 public static final int DELAY = 100; // milliseconds 068 private boolean exiting = false; 069 private final Serial serial; 070 private final List<SerialDataListener> listeners; 071 072 /** 073 * <p> Default constructor </p> 074 * <p> NOTE: This class is used internal to the Pi4J library by the SerialImpl class.</p> 075 * 076 * @param serial A class that implements the 'Serial' interface. 077 * @param listeners A collection of class instances that implement the SerialListener interface. 078 */ 079 public SerialDataMonitorThread(Serial serial, CopyOnWriteArrayList<SerialDataListener> listeners) { 080 this.serial = serial; 081 this.listeners = listeners; 082 } 083 084 /** 085 * Exit the monitoring thread. 086 */ 087 public synchronized void shutdown() { 088 exiting = true; 089 } 090 091 /** 092 * This method is called when this monitoring thread starts 093 */ 094 public void run() { 095 StringBuilder buffer = new StringBuilder(); 096 097 while (!exiting) { 098 if (serial.isOpen()) { 099 if (serial.availableBytes() > 0) { 100 // reset buffer data 101 buffer.setLength(0); 102 103 // reset data from serial port 104 while (serial.availableBytes() > 0) 105 buffer.append(serial.read()); 106 107 // when done reading, emit the event if there are any listeners 108 if (!listeners.isEmpty()) { 109 // iterate over the listeners and send the data events 110 SerialDataEvent event = new SerialDataEvent(serial, buffer.toString()); 111 for (SerialDataListener sdl : listeners) { 112 sdl.dataReceived(event); 113 } 114 } 115 } 116 } 117 118 // wait for a small interval before attempting to read serial data again 119 try { 120 Thread.sleep(DELAY); 121 } catch (InterruptedException e) { 122 e.printStackTrace(); 123 } 124 } 125 } 126}