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Merge pull request #243 from Ueland/SignalStrengthMonitor
Implemented Signal Strength Monitor
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155 changes: 155 additions & 0 deletions
155
app/src/main/java/com/SecUpwN/AIMSICD/service/SignalStrengthTracker.java
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,155 @@ | ||
| package com.SecUpwN.AIMSICD.service; | ||
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| import android.content.Context; | ||
| import android.hardware.Sensor; | ||
| import android.hardware.SensorEvent; | ||
| import android.hardware.SensorEventListener; | ||
| import android.util.Log; | ||
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| import com.SecUpwN.AIMSICD.adapters.AIMSICDDbAdapter; | ||
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| import java.util.ArrayList; | ||
| import java.util.HashMap; | ||
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| /** | ||
| * | ||
| * Class that calculates cell signal strength averages and decides if a given cell + strength | ||
| * appears to be mysteriously (low or high) | ||
| * | ||
| * https://cloud.githubusercontent.com/assets/2507905/4428863/c85c8366-45d4-11e4-89da-c650cdb56caf.jpg | ||
| * | ||
| * @author Tor Henning Ueland | ||
| */ | ||
| public class SignalStrengthTracker { | ||
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| public static final String TAG = "SignalStrengthMonitor"; | ||
| private static int sleepTimeBetweenSignalRegistration = 30; //seconds | ||
| private static int sleepTimeBetweenPersistation = 900; //seconds | ||
| private static int minimumIdleTime = 30; //seconds | ||
| private static int maximumNumberOfDaysSaved = 60; //days | ||
| private static int mysteriousSignalDifference = 10; //DB | ||
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| private HashMap<Integer, Long> lastRegistration = new HashMap<>(); | ||
| private HashMap<Integer, ArrayList<Integer>> toCalculate = new HashMap<>(); | ||
| private HashMap<Integer, Integer> averageSignalCache = new HashMap<>(); | ||
| private long lastPersistTime = 0; | ||
| private long lastMovementDetected = 0l; | ||
| private AIMSICDDbAdapter mDbHelper; | ||
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| public SignalStrengthTracker(Context context) { | ||
| lastMovementDetected = System.currentTimeMillis(); | ||
| lastPersistTime = System.currentTimeMillis(); | ||
| mDbHelper = new AIMSICDDbAdapter(context); | ||
| } | ||
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| /** | ||
| * Registers a new cell signal strength for future calculation, | ||
| * only values older than $sleepTimeBetweenSignalRegistration seconds | ||
| * since last registration is saved for processing. | ||
| * @param cellID | ||
| * @param signalStrength | ||
| */ | ||
| public void registerSignalStrength(int cellID, int signalStrength) { | ||
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| long now = System.currentTimeMillis(); | ||
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| if(deviceIsMoving()) { | ||
| Log.i(TAG, "Ignored signal strength sample for cell ID #"+cellID+" as the device is currently moving around, will not accept anything for another "+((minimumIdleTime*1000) - (now - lastMovementDetected))+"ms"); | ||
| return; | ||
| } | ||
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| if(!lastRegistration.containsKey(cellID) || now-(sleepTimeBetweenSignalRegistration*1000) > lastRegistration.get(cellID)) { | ||
| long diff = -1; | ||
| if(lastRegistration.get(cellID) != null) { | ||
| diff = now - lastRegistration.get(cellID); | ||
| } | ||
| lastRegistration.put(cellID, now); | ||
| if(toCalculate.get(cellID) == null) { | ||
| toCalculate.put(cellID, new ArrayList<Integer>(1)); | ||
| } | ||
| Log.i(TAG, "Scheduling signal strength calculation from cell #" + cellID + " @ " + signalStrength + "DB, last registration was "+diff+"ms ago"); | ||
| toCalculate.get(cellID).add(signalStrength); | ||
| lastRegistration.put(cellID, now); | ||
| } | ||
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| if(now-(sleepTimeBetweenPersistation*1000) > lastPersistTime) { | ||
| Log.i(TAG, "Saving cell signal data, last save was "+(now-lastPersistTime)+"ms ago"); | ||
| cleanupOldData(); | ||
| persistData(); | ||
| lastPersistTime = now; | ||
| } | ||
| } | ||
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| /* | ||
| Move data from temp cache into DB | ||
| */ | ||
| private void persistData() { | ||
| mDbHelper.open(); | ||
| for(int cellID : toCalculate.keySet()) { | ||
| for(int signal : toCalculate.get(cellID)) { | ||
| mDbHelper.addSignalStrength(cellID, signal, lastRegistration.get(cellID)); | ||
| } | ||
| } | ||
| mDbHelper.close(); | ||
| toCalculate.clear(); | ||
| } | ||
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| /* | ||
| Remove data from DB older than N days (days * number of seconds in a day)*seconds to milliseconds | ||
| */ | ||
| private void cleanupOldData() { | ||
| long maxTime = (System.currentTimeMillis() - ((maximumNumberOfDaysSaved*86400))*1000); | ||
| mDbHelper.open(); | ||
| mDbHelper.cleanseCellStrengthTables(maxTime); | ||
| mDbHelper.close(); | ||
| averageSignalCache.clear(); | ||
| } | ||
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| private boolean deviceIsMoving() { | ||
| return System.currentTimeMillis() - lastMovementDetected < minimumIdleTime*1000; | ||
| } | ||
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| /** | ||
| * Uses previously saved calculations and signal measurements to guesstimate if a given signal | ||
| * strength for a given cell ID looks mysterious or not. | ||
| * @param cellID | ||
| * @param signalStrength | ||
| */ | ||
| public boolean isMysterious(int cellID, int signalStrength) { | ||
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| //If moving, return false | ||
| if(deviceIsMoving()) { | ||
| Log.i(TAG, "Cannot check if the signal strength for cell ID #"+cellID+" as the device is currently moving around."); | ||
| return false; | ||
| } | ||
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| int storedAvg; | ||
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| //Cached? | ||
| if(averageSignalCache.get(cellID) != null) { | ||
| storedAvg = averageSignalCache.get(cellID); | ||
| Log.d(TAG, "Cached average for cell ID #"+cellID+" is "+storedAvg); | ||
| } else { | ||
| //Not cached, check DB | ||
| mDbHelper.open(); | ||
| storedAvg = mDbHelper.getAverageSignalStrength(cellID); | ||
| averageSignalCache.put(cellID, storedAvg); | ||
| Log.d(TAG, "Cached average in DB for cell ID #"+cellID+" is "+storedAvg); | ||
| mDbHelper.close(); | ||
| } | ||
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| boolean result; | ||
| if(storedAvg > signalStrength) { | ||
| result = storedAvg - signalStrength > mysteriousSignalDifference; | ||
| } else { | ||
| result = signalStrength- storedAvg > mysteriousSignalDifference; | ||
| } | ||
| Log.d(TAG, "Signal strength mystery check for cell ID #"+cellID+" is "+result+", avg:"+storedAvg+", this signal: "+signalStrength); | ||
| return result; | ||
| } | ||
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| public void onSensorChanged() { | ||
| //Log.d(TAG, "We are moving..."); | ||
| lastMovementDetected = System.currentTimeMillis(); | ||
| } | ||
| } |