processing/java/libraries/io/src/processing/io/LED.java at master · bernardoprd/processing · GitHub

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/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */

Hardware I/O library developed by Gottfried Haider as part of GSoC 2015

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General

Public License along with this library; if not, write to the

Free Software Foundation, Inc., 59 Temple Place, Suite 330,

Boston, MA 02111-1307 USA

package processing.io;

import processing.io.NativeInterface;

import java.io.File;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.Arrays;

/**

* @webref

public class LED {

protected String dev;

protected int maxBrightness;

protected int prevBrightness;

protected String prevTrigger;

/**

* Opens a LED device

* @param dev device name

* @see list

* @webref

public LED(String dev) {

NativeInterface.loadLibrary();

this.dev = dev;

if (NativeInterface.isSimulated()) {

return;

}

// read maximum brightness

try {

Path path = Paths.get("/sys/class/leds/" + dev + "/max_brightness");

String tmp = new String(Files.readAllBytes(path));

maxBrightness = Integer.parseInt(tmp.trim());

} catch (Exception e) {

System.err.println(e.getMessage());

throw new RuntimeException("Unable to read maximum brightness");

}

// read current trigger setting to be able to restore it later

try {

Path path = Paths.get("/sys/class/leds/" + dev + "/trigger");

String tmp = new String(Files.readAllBytes(path));

int start = tmp.indexOf('[');

int end = tmp.indexOf(']', start);

if (start != -1 && end != -1) {

prevTrigger = tmp.substring(start+1, end);

}

} catch (Exception e) {

System.err.println(e.getMessage());

throw new RuntimeException("Unable to read trigger setting");

}

// read current brightness to be able to restore it later

try {

Path path = Paths.get("/sys/class/leds/" + dev + "/brightness");

String tmp = new String(Files.readAllBytes(path));

prevBrightness = Integer.parseInt(tmp.trim());

} catch (Exception e) {

System.err.println(e.getMessage());

throw new RuntimeException("Unable to read current brightness");

}

// disable trigger

String fn = "/sys/class/leds/" + dev + "/trigger";

int ret = NativeInterface.writeFile(fn, "none");

if (ret < 0) {

if (ret == -13) { // EACCES

System.err.println("You might need to install a custom udev rule to allow regular users to modify /sys/class/leds/*.");

}

throw new RuntimeException(NativeInterface.getError(ret));

}

/**

* Sets the brightness

* @param bright 0.0 (off) to 1.0 (maximum)

* @webref

public void brightness(float bright) {

if (bright < 0.0 || 1.0 < bright) {

System.err.println("Brightness must be between 0.0 and 1.0.");

throw new IllegalArgumentException("Illegal argument");

}

if (NativeInterface.isSimulated()) {

return;

}

String fn = "/sys/class/leds/" + dev + "/brightness";

int ret = NativeInterface.writeFile(fn, Integer.toString((int)(bright * maxBrightness)));

if (ret < 0) {

throw new RuntimeException(fn + ": " + NativeInterface.getError(ret));

}

/**

* Restores the previous state

* @webref

public void close() {

if (NativeInterface.isSimulated()) {

return;

}

// restore previous settings

String fn = "/sys/class/leds/" + dev + "/brightness";

int ret = NativeInterface.writeFile(fn, Integer.toString(prevBrightness));

if (ret < 0) {

throw new RuntimeException(fn + ": " + NativeInterface.getError(ret));

}

fn = "/sys/class/leds/" + dev + "/trigger";

ret = NativeInterface.writeFile(fn, prevTrigger);

if (ret < 0) {

throw new RuntimeException(fn + ": " + NativeInterface.getError(ret));

}

/**

* Lists all available LED devices

* @return String array

* @webref

public static String[] list() {

if (NativeInterface.isSimulated()) {

// as on the Raspberry Pi

return new String[]{ "led0", "led1" };

}

ArrayList<String> devs = new ArrayList<String>();

File dir = new File("/sys/class/leds");

File[] files = dir.listFiles();

if (files != null) {

for (File file : files) {

devs.add(file.getName());

}

// listFiles() does not guarantee ordering

String[] tmp = devs.toArray(new String[devs.size()]);

Arrays.sort(tmp);

return tmp;

}

processing/java/libraries/io/src/processing/io/LED.java at master · bernardoprd/processing · GitHub

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