001package com.pi4j.io.i2c; 002 003/* 004 * #%L 005 * ********************************************************************** 006 * ORGANIZATION : Pi4J 007 * PROJECT : Pi4J :: Java Library (Core) 008 * FILENAME : I2CFactory.java 009 * 010 * This file is part of the Pi4J project. More information about 011 * this project can be found here: https://www.pi4j.com/ 012 * ********************************************************************** 013 * %% 014 * Copyright (C) 2012 - 2019 Pi4J 015 * %% 016 * This program is free software: you can redistribute it and/or modify 017 * it under the terms of the GNU Lesser General Public License as 018 * published by the Free Software Foundation, either version 3 of the 019 * License, or (at your option) any later version. 020 * 021 * This program is distributed in the hope that it will be useful, 022 * but WITHOUT ANY WARRANTY; without even the implied warranty of 023 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 024 * GNU General Lesser Public License for more details. 025 * 026 * You should have received a copy of the GNU General Lesser Public 027 * License along with this program. If not, see 028 * <http://www.gnu.org/licenses/lgpl-3.0.html>. 029 * #L% 030 */ 031 032import java.io.IOException; 033import java.nio.file.Files; 034import java.nio.file.Path; 035import java.nio.file.Paths; 036import java.util.HashSet; 037import java.util.Set; 038import java.util.concurrent.TimeUnit; 039 040import com.pi4j.io.i2c.impl.I2CProviderImpl; 041 042/** 043 * I2C factory - it returns instances of {@link I2CBus} interface. 044 * 045 * @author Robert Savage (<a href="http://www.savagehomeautomation.com">http://www .savagehomeautomation.com</a>) 046 */ 047public class I2CFactory { 048 049 public static final long DEFAULT_LOCKAQUIRE_TIMEOUT = 1000; 050 051 public static final TimeUnit DEFAULT_LOCKAQUIRE_TIMEOUT_UNITS = TimeUnit.MILLISECONDS; 052 053 public static class UnsupportedBusNumberException extends Exception { 054 private static final long serialVersionUID = 1L; 055 056 public UnsupportedBusNumberException() { 057 super(); 058 } 059 } 060 061 volatile static I2CFactoryProvider provider = new I2CProviderImpl(); 062 063 // private constructor 064 private I2CFactory() { 065 // forbid object construction 066 } 067 068 /** 069 * Create new I2CBus instance. 070 * <p> 071 * The timeout for locking the bus for exclusive communication is set to DEFAULT_LOCKAQUIRE_TIMEOUT. 072 * 073 * @param busNumber The bus number 074 * @return Return a new I2CBus instance 075 * @throws UnsupportedBusNumberException If the given bus-number is not supported by the underlying system 076 * @throws IOException If communication to i2c-bus fails 077 * @see I2CFactory#DEFAULT_LOCKAQUIRE_TIMEOUT 078 * @see I2CFactory#DEFAULT_LOCKAQUIRE_TIMEOUT_UNITS 079 */ 080 public static I2CBus getInstance(int busNumber) throws UnsupportedBusNumberException, IOException { 081 return provider.getBus(busNumber, DEFAULT_LOCKAQUIRE_TIMEOUT, DEFAULT_LOCKAQUIRE_TIMEOUT_UNITS); 082 } 083 084 /** 085 * Create new I2CBus instance. 086 * 087 * @param busNumber The bus number 088 * @param lockAquireTimeout The timeout for locking the bus for exclusive communication 089 * @param lockAquireTimeoutUnit The units of lockAquireTimeout 090 * @return Return a new I2CBus instance 091 * @throws UnsupportedBusNumberException If the given bus-number is not supported by the underlying system 092 * @throws IOException If communication to i2c-bus fails 093 */ 094 public static I2CBus getInstance(int busNumber, long lockAquireTimeout, TimeUnit lockAquireTimeoutUnit) throws UnsupportedBusNumberException, IOException { 095 return provider.getBus(busNumber, lockAquireTimeout, lockAquireTimeoutUnit); 096 } 097 098 /** 099 * allow changing the provider for the factory 100 * 101 * @param factoryProvider 102 */ 103 public static void setFactory(I2CFactoryProvider factoryProvider) { 104 provider = factoryProvider; 105 } 106 107 /** 108 * Fetch all available I2C bus numbers from sysfs. 109 * Returns null, if nothing was found. 110 * 111 * @return Return found I2C bus numbers or null 112 * @throws IOException If fetching from sysfs interface fails 113 */ 114 public static int[] getBusIds() throws IOException { 115 Set<Integer> set = null; 116 for (Path device: Files.newDirectoryStream(Paths.get("/sys/bus/i2c/devices"), "*")) { 117 String[] tokens = device.toString().split("-"); 118 if (tokens.length == 2) { 119 if (set == null) { 120 set = new HashSet<Integer>(); 121 } 122 set.add(Integer.valueOf(tokens[1])); 123 } 124 } 125 126 int[] result = null; 127 if (set != null) { 128 int counter = 0; 129 result = new int[set.size()]; 130 for (Integer value : set) { 131 result[counter] = value.intValue(); 132 counter = counter + 1; 133 } 134 } 135 return result; 136 } 137}