com.amazonaws.services.iot.demo.danbo.rpi.Servo.java Source code

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Here is the source code for com.amazonaws.services.iot.demo.danbo.rpi.Servo.java

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/** 
 * Copyright 2015 Amazon.com, Inc. or its affiliates. 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. A copy of the License is located at
 *
 *     http://aws.amazon.com/apache2.0/
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.iot.demo.danbo.rpi;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * This class implements the execution of a servo command. It actually only
 * encapsulates calls to the servoblaster driver.
 * 
 * @author Fabio Silva (silfabio@amazon.com)
 */
public class Servo implements Runnable {
    public static int currentAngle = 0;
    private Log log = LogFactory.getLog(Servo.class);
    private String threadName = "";
    private int angle;

    public Servo(String threadName, int angle) {
        this.threadName = threadName;
        this.angle = angle;
    }

    public void run() {
        try {
            log.debug("starting execution of thread: " + threadName);
            // calls the servoblaster command to move the servo according to the
            // selected angle
            try {
                String servoBlasterDevice = "/dev/servoblaster";
                File servoBlasterDev = new File(servoBlasterDevice);
                if (!servoBlasterDev.exists()) {
                    throw new FileNotFoundException("Servoblaster not found at " + servoBlasterDevice
                            + ". Please check https://github.com/richardghirst/PiBits/tree/master/ServoBlaster for details.");
                }
                FileWriter writer = new FileWriter(servoBlasterDev);
                StringBuilder b = new StringBuilder();
                b.append("0").append('=').append(Integer.toString(angle + 150)).append('\n');
                try {
                    writer.write(b.toString());
                    writer.flush();
                } catch (IOException e) {
                    try {
                        writer.close();
                    } catch (IOException ignore) {
                    }
                }
                try {
                    writer.write(b.toString());
                    writer.flush();
                } catch (IOException e) {
                    throw new RuntimeException("Failed to write to /dev/servoblaster device", e);
                }
            } catch (Exception e) {
                System.err.println(String.format("Could not execute the servoblaster command"));
                e.printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            log.debug("finishing execution of thread: " + threadName);
        }
    }
}