Merge branch 'thermostat-feature' into 'dev'

Thermostat feature

See merge request sa4-2020/the-sanmarinoes/backend!77

socket_test.html

@@ -29,8 +29,10 @@ connection.onopen = function(evt) {
 connection.onmessage = function(evt) {
   console.log("***ONMESSAGE", evt);
   let data = JSON.parse(evt.data);
+  let a = document.getElementById("giovanni");
+  if (a) a.remove();
 
-  malusa.innerHTML += "<p><pre>" + JSON.stringify(JSON.parse(evt.data), null, 2) + "</pre></p>";
+  malusa.innerHTML += "<pre id=\"giovanni\">" + JSON.stringify(JSON.parse(evt.data), null, 2) + "</pre>";
 };
 
 connection.onerror = function(evt) {

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/config/JWTRequestFilter.java

@@ -1,6 +1,6 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.config;
 
-import ch.usi.inf.sa4.sanmarinoes.smarthut.models.JWTUserDetailsService;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.JWTUserDetailsService;
 import io.jsonwebtoken.ExpiredJwtException;
 import java.io.IOException;
 import javax.servlet.FilterChain;

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/config/SpringFoxConfig.java

@@ -68,6 +68,7 @@ public class SpringFoxConfig {
                 .or(PathSelectors.regex("/room.*")::apply)
                 .or(PathSelectors.regex("/device.*")::apply)
                 .or(PathSelectors.regex("/buttonDimmer.*")::apply)
+                .or(PathSelectors.regex("/thermostat.*")::apply)
                 .or(PathSelectors.regex("/dimmableLight.*")::apply)
                 .or(PathSelectors.regex("/knobDimmer.*")::apply)
                 .or(PathSelectors.regex("/regularLight.*")::apply)

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/config/WebSecurityConfig.java

@@ -1,6 +1,6 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.config;
 
-import ch.usi.inf.sa4.sanmarinoes.smarthut.models.JWTUserDetailsService;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.JWTUserDetailsService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/AuthenticationController.java

@@ -8,6 +8,8 @@ import ch.usi.inf.sa4.sanmarinoes.smarthut.error.UserNotFoundException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
 import java.security.Principal;
 import javax.validation.Valid;
+
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.JWTUserDetailsService;
 import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.authentication.BadCredentialsException;
 import org.springframework.security.authentication.DisabledException;

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/RoomController.java

@@ -5,6 +5,7 @@ import static ch.usi.inf.sa4.sanmarinoes.smarthut.utils.Utils.toList;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.RoomSaveRequest;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.error.NotFoundException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.ThermostatService;
 import java.security.Principal;
 import java.util.*;
 import javax.validation.Valid;
@@ -29,6 +30,8 @@ public class RoomController {
 
     @Autowired private KnobDimmerRepository knobDimmerRepository;
 
+    @Autowired private ThermostatService thermostatService;
+
     @GetMapping
     public List<Room> findAll() {
         return toList(roomRepository.findAll());
@@ -99,6 +102,12 @@ public class RoomController {
      */
     @GetMapping(path = "/{roomId}/devices")
     public List<Device> getDevices(@PathVariable("roomId") long roomid) {
-        return deviceRepository.findByRoomId(roomid);
+        Iterable<Device> devices = deviceRepository.findByRoomId(roomid);
+        for (Device d : devices) {
+            if (d instanceof Thermostat) {
+                thermostatService.populateMeasuredTemperature((Thermostat) d);
+            }
+        }
+        return toList(devices);
     }
 }

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/SensorController.java

@@ -5,12 +5,15 @@ import static ch.usi.inf.sa4.sanmarinoes.smarthut.utils.Utils.toList;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.SensorSaveRequest;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.error.NotFoundException;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.SensorService;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.socket.SensorSocketEndpoint;
+
 import java.math.BigDecimal;
 import java.security.Principal;
 import java.util.*;
 import java.util.List;
 import javax.validation.Valid;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.*;
 import org.springframework.web.bind.annotation.*;
@@ -20,9 +23,14 @@ import org.springframework.web.bind.annotation.*;
 @RequestMapping("/sensor")
 public class SensorController {
 
-    @Autowired private SensorRepository sensorRepository;
+    @Autowired
+    private SensorRepository sensorRepository;
 
-    @Autowired private SensorSocketEndpoint sensorSocketEndpoint;
+    @Autowired
+    private SensorSocketEndpoint sensorSocketEndpoint;
+
+    @Autowired
+    private SensorService sensorService;
 
     @GetMapping
     public List<Sensor> findAll() {
@@ -45,29 +53,13 @@ public class SensorController {
         return sensorRepository.save(newSensor);
     }
 
-    /**
-     * Updates the sensor with new measurement and propagates update through websocket
-     *
-     * @param sensor the sensor to update
-     * @param value the new measurement
-     * @return the updated sensor
-     */
-    public Sensor updateValueFromSensor(Sensor sensor, BigDecimal value) {
-        sensor.setValue(value);
-        final Sensor toReturn = sensorRepository.save(sensor);
-
-        sensorSocketEndpoint.queueDeviceUpdate(sensor, sensorRepository.findUser(sensor.getId()));
-
-        return toReturn;
-    }
-
     @PutMapping("/{id}/value")
     public Sensor updateValue(
             @PathVariable("id") Long sensorId,
             @RequestParam("value") BigDecimal value,
             final Principal principal)
             throws NotFoundException {
-        return updateValueFromSensor(
+        return sensorService.updateValueFromSensor(
                 sensorRepository
                         .findByIdAndUsername(sensorId, principal.getName())
                         .orElseThrow(NotFoundException::new),

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/controller/ThermostatController.java

@@ -0,0 +1,75 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.controller;
+
+import ch.usi.inf.sa4.sanmarinoes.smarthut.dto.ThermostatSaveRequest;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.error.NotFoundException;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.ThermostatService;
+import java.security.Principal;
+import java.util.*;
+import java.util.List;
+import javax.validation.Valid;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.*;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@EnableAutoConfiguration
+@RequestMapping("/thermostat")
+public class ThermostatController {
+
+    @Autowired private ThermostatRepository thermostatRepository;
+
+    @Autowired private ThermostatService thermostatService;
+
+    @GetMapping
+    public List<Thermostat> findAll(Principal user) {
+        return thermostatService.findAll(user.getName());
+    }
+
+    @GetMapping("/{id}")
+    public Thermostat findById(@PathVariable("id") long id, Principal principal)
+            throws NotFoundException {
+        return thermostatService
+                .findById(id, principal.getName())
+                .orElseThrow(NotFoundException::new);
+    }
+
+    private Thermostat save(Thermostat newT, ThermostatSaveRequest t) {
+        newT.setTargetTemperature(t.getTargetTemperature());
+        newT.setId(t.getId());
+        newT.setName(t.getName());
+        newT.setRoomId(t.getRoomId());
+        newT.setUseExternalSensors(t.isUseExternalSensors());
+
+        if (t.isTurnOn()) {
+            newT.setState(Thermostat.ThermostatState.IDLE);
+            thermostatService.computeState(newT);
+        } else {
+            newT.setState(Thermostat.ThermostatState.OFF);
+        }
+
+        newT = thermostatRepository.save(newT);
+        thermostatService.populateMeasuredTemperature(newT);
+        return newT;
+    }
+
+    @PostMapping
+    public Thermostat create(@Valid @RequestBody ThermostatSaveRequest t) {
+        return save(new Thermostat(), t);
+    }
+
+    @PutMapping
+    public Thermostat update(@Valid @RequestBody ThermostatSaveRequest t, final Principal principal)
+            throws NotFoundException {
+        return save(
+                thermostatRepository
+                        .findByIdAndUsername(t.getId(), principal.getName())
+                        .orElseThrow(NotFoundException::new),
+                t);
+    }
+
+    @DeleteMapping("/{id}")
+    public void deleteById(@PathVariable("id") long id) {
+        thermostatRepository.deleteById(id);
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/dto/ThermostatSaveRequest.java

@@ -0,0 +1,75 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.dto;
+
+import java.math.BigDecimal;
+import javax.validation.constraints.NotNull;
+
+public class ThermostatSaveRequest {
+
+    /** Device identifier */
+    private long id;
+
+    /**
+     * The room this device belongs in, as a foreign key id. To use when updating and inserting from
+     * a REST call.
+     */
+    @NotNull private Long roomId;
+
+    /** The name of the device as assigned by the user (e.g. 'Master bedroom light') */
+    @NotNull private String name;
+
+    /** Temperature to be reached */
+    @NotNull private BigDecimal targetTemperature;
+
+    @NotNull private boolean useExternalSensors;
+
+    /** State of this thermostat */
+    @NotNull private boolean turnOn;
+
+    public boolean isTurnOn() {
+        return turnOn;
+    }
+
+    public void setTurnOn(boolean turnOn) {
+        this.turnOn = turnOn;
+    }
+
+    public boolean isUseExternalSensors() {
+        return useExternalSensors;
+    }
+
+    public void setUseExternalSensors(boolean useExternalSensors) {
+        this.useExternalSensors = useExternalSensors;
+    }
+
+    public BigDecimal getTargetTemperature() {
+        return this.targetTemperature;
+    }
+
+    public void setTargetTemperature(BigDecimal targetTemperature) {
+        this.targetTemperature = targetTemperature;
+    }
+
+    public void setRoomId(Long roomId) {
+        this.roomId = roomId;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public long getId() {
+        return id;
+    }
+
+    public Long getRoomId() {
+        return roomId;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/SensorRepository.java

@@ -1,3 +1,7 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
 
-public interface SensorRepository extends DeviceRepository<Sensor> {}
+import java.util.List;
+
+public interface SensorRepository extends DeviceRepository<Sensor> {
+    List<Sensor> findAllBySensor(Sensor.SensorType sensor);
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/Thermostat.java

@@ -0,0 +1,85 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
+
+import com.google.gson.annotations.SerializedName;
+import java.math.BigDecimal;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Transient;
+import javax.validation.constraints.NotNull;
+
+/** A thermostat capable of controlling cooling and heating. */
+@Entity
+public class Thermostat extends OutputDevice {
+
+    public enum ThermostatState {
+        @SerializedName("OFF")
+        OFF,
+        @SerializedName("IDLE")
+        IDLE,
+        @SerializedName("COOLING")
+        COOLING,
+        @SerializedName("HEATING")
+        HEATING
+    }
+
+    /** Temperature to be reached */
+    @Column @NotNull private BigDecimal targetTemperature;
+
+    /** The temperature detected by the embedded sensor */
+    @Column(nullable = false, precision = 4, scale = 1)
+    private BigDecimal internalSensorTemperature =
+            Sensor.TYPICAL_VALUES.get(Sensor.SensorType.TEMPERATURE);
+
+    /** State of this thermostat */
+    @Column @NotNull private ThermostatState state;
+
+    @Transient private BigDecimal measuredTemperature;
+
+    @Column private boolean useExternalSensors = false;
+
+    /** Creates a thermostat with a temperature sensor and its initial OFF state */
+    public Thermostat() {
+        super("thermostat");
+        this.state = ThermostatState.OFF;
+    }
+
+    public void setState(ThermostatState state) {
+        this.state = state;
+    }
+
+    public ThermostatState getState() {
+        return this.state;
+    }
+
+    public BigDecimal getTargetTemperature() {
+        return this.targetTemperature;
+    }
+
+    public BigDecimal getInternalSensorTemperature() {
+        return internalSensorTemperature;
+    }
+
+    public boolean isUseExternalSensors() {
+        return useExternalSensors;
+    }
+
+    public BigDecimal getMeasuredTemperature() {
+        return measuredTemperature;
+    }
+
+    public void setMeasuredTemperature(BigDecimal measuredTemperature) {
+        this.measuredTemperature = measuredTemperature;
+    }
+
+    public void setTargetTemperature(BigDecimal targetTemperature) {
+        this.targetTemperature = targetTemperature;
+    }
+
+    public void setInternalSensorTemperature(BigDecimal internalSensorTemperature) {
+        this.internalSensorTemperature = internalSensorTemperature;
+    }
+
+    public void setUseExternalSensors(boolean useExternalSensors) {
+        this.useExternalSensors = useExternalSensors;
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/models/ThermostatRepository.java

@@ -0,0 +1,30 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
+
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Optional;
+import javax.transaction.Transactional;
+import org.springframework.data.jpa.repository.Query;
+
+public interface ThermostatRepository extends DeviceRepository<Thermostat> {
+
+    /**
+     * Finds all devices belonging to a user
+     *
+     * @param username the User's username
+     * @return all devices of that user
+     */
+    @Transactional
+    @Query("SELECT t FROM Thermostat t JOIN t.room r JOIN r.user u WHERE u.username = ?1")
+    List<Thermostat> findAllByUsername(String username);
+
+    /**
+     * Computes the average temperature of all temperature sensors in the room
+     *
+     * @param thermostatRoomId room ID of the thermostat
+     * @return an optional big decimal, empty if none found
+     */
+    @Query(
+            "SELECT AVG(s.value) FROM Sensor s JOIN s.room r WHERE s.sensor = 'TEMPERATURE' AND r.id = ?1")
+    Optional<BigDecimal> getAverageTemperature(Long thermostatRoomId);
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/scheduled/UpdateTasks.java

@@ -1,10 +1,10 @@
 package ch.usi.inf.sa4.sanmarinoes.smarthut.scheduled;
 
 import ch.usi.inf.sa4.sanmarinoes.smarthut.controller.MotionSensorController;
-import ch.usi.inf.sa4.sanmarinoes.smarthut.controller.SensorController;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.models.*;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.SensorService;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.service.ThermostatService;
 import ch.usi.inf.sa4.sanmarinoes.smarthut.socket.SensorSocketEndpoint;
-import java.math.BigDecimal;
 import java.util.Collection;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
@@ -26,24 +26,24 @@ public class UpdateTasks {
 
     @Autowired private SmartPlugRepository smartPlugRepository;
 
-    @Autowired private SensorController sensorController;
+    @Autowired private SensorService sensorService;
+
+    @Autowired private ThermostatService thermostatService;
 
     @Autowired private MotionSensorController motionSensorController;
 
     @Autowired private SensorSocketEndpoint sensorSocketEndpoint;
 
-    /** Generates fake sensor updates every two seconds with a +/- 1.25% error */
+    /** Generates fake sensor updates every two seconds with a +/- 2.5% error */
     @Scheduled(fixedRate = 2000)
     public void sensorFakeUpdate() {
-        StreamSupport.stream(sensorRepository.findAll().spliterator(), true)
-                .forEach(
-                        sensor ->
-                                sensorController.updateValueFromSensor(
-                                        sensor,
-                                        Sensor.TYPICAL_VALUES
-                                                .get(sensor.getSensor())
-                                                .multiply(
-                                                        BigDecimal.valueOf(0.9875 + Math.random() / 40))));
+        sensorService.sensorFakeUpdate();
+    }
+
+    /** Generates fake sensor updates every two seconds with a +/- 2.5% error */
+    @Scheduled(fixedRate = 2000)
+    public void thermostatInteralSensorFakeUpdate() {
+        thermostatService.fakeUpdateAll();
     }
 
     /**
@@ -71,7 +71,10 @@ public class UpdateTasks {
     public void smartPlugConsumptionFakeUpdate() {
         smartPlugRepository.updateTotalConsumption(SmartPlug.AVERAGE_CONSUMPTION_KW);
         final Collection<SmartPlug> c = smartPlugRepository.findByOn(true);
-        c.forEach(s -> sensorSocketEndpoint.queueDeviceUpdate(s, sensorRepository.findUser(s.getId())));
+        c.forEach(
+                s ->
+                        sensorSocketEndpoint.queueDeviceUpdate(
+                                s, sensorRepository.findUser(s.getId())));
     }
 
     /** Sends device updates through sensor socket in batch every one second */

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/JWTUserDetailsService.java

@@ -1,6 +1,9 @@
-package ch.usi.inf.sa4.sanmarinoes.smarthut.models;
+package ch.usi.inf.sa4.sanmarinoes.smarthut.service;
 
 import java.util.Set;
+
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.User;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.UserRepository;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.security.core.*;
 import org.springframework.security.core.userdetails.UserDetails;

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/SensorService.java

@@ -0,0 +1,47 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.service;
+
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.Sensor;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.SensorRepository;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.socket.SensorSocketEndpoint;
+import java.math.BigDecimal;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class SensorService {
+
+    @Autowired private SensorRepository sensorRepository;
+
+    @Autowired private ThermostatService thermostatService;
+
+    @Autowired private SensorSocketEndpoint endpoint;
+
+    private void randomJitter(Sensor sensor) {
+        updateValueFromSensor(
+                sensor,
+                Sensor.TYPICAL_VALUES
+                        .get(sensor.getSensor())
+                        .multiply(BigDecimal.valueOf(0.975 + Math.random() / 20)));
+    }
+
+    public void sensorFakeUpdate() {
+        sensorRepository.findAll().forEach(this::randomJitter);
+        thermostatService.updateStates();
+    }
+
+    /**
+     * Updates the sensor with new measurement and propagates update through websocket
+     *
+     * @param sensor the sensor to update
+     * @param value the new measurement
+     * @return the updated sensor
+     */
+    public Sensor updateValueFromSensor(Sensor sensor, BigDecimal value) {
+        sensor.setValue(value);
+        final Sensor toReturn = sensorRepository.save(sensor);
+
+        endpoint.queueDeviceUpdate(sensor, sensorRepository.findUser(sensor.getId()));
+
+        return toReturn;
+    }
+}

src/main/java/ch/usi/inf/sa4/sanmarinoes/smarthut/service/ThermostatService.java

@@ -0,0 +1,110 @@
+package ch.usi.inf.sa4.sanmarinoes.smarthut.service;
+
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.Sensor;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.Thermostat;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.models.ThermostatRepository;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.socket.SensorSocketEndpoint;
+import ch.usi.inf.sa4.sanmarinoes.smarthut.utils.Utils;
+import java.math.BigDecimal;
+import java.util.List;
+import java.util.Optional;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ThermostatService {
+
+    @Autowired private SensorSocketEndpoint endpoint;
+
+    @Autowired private ThermostatRepository thermostatRepository;
+
+    private void randomJitter(Thermostat thermostat) {
+        updateValueForThermostat(
+                thermostat,
+                Sensor.TYPICAL_VALUES
+                        .get(Sensor.SensorType.TEMPERATURE)
+                        .multiply(BigDecimal.valueOf(0.975 + Math.random() / 20)));
+    }
+
+    private void updateValueForThermostat(Thermostat thermostat, BigDecimal value) {
+        thermostat.setInternalSensorTemperature(value);
+        thermostatRepository.save(thermostat);
+    }
+
+    public void fakeUpdateAll() {
+        thermostatRepository.findAll().forEach(this::randomJitter);
+        updateStates();
+    }
+
+    public List<Thermostat> findAll(String username) {
+        Iterable<Thermostat> all = thermostatRepository.findAllByUsername(username);
+        all.forEach(this::populateMeasuredTemperature);
+        return Utils.toList(all);
+    }
+
+    public boolean computeState(Thermostat t) {
+        if (t.getState() == Thermostat.ThermostatState.OFF) {
+            return false;
+        }
+
+        populateMeasuredTemperature(t);
+        BigDecimal measured = t.getMeasuredTemperature();
+        BigDecimal target = t.getTargetTemperature();
+        BigDecimal delta = target.subtract(measured);
+
+        if (delta.abs().doubleValue() < 0.25) {
+            if (t.getState() == Thermostat.ThermostatState.IDLE) return false;
+            t.setState(Thermostat.ThermostatState.IDLE);
+        } else if (delta.signum() > 0) {
+            if (t.getState() == Thermostat.ThermostatState.HEATING) return false;
+            t.setState(Thermostat.ThermostatState.HEATING);
+        } else {
+            if (t.getState() == Thermostat.ThermostatState.COOLING) return false;
+            t.setState(Thermostat.ThermostatState.COOLING);
+        }
+
+        return true;
+    }
+
+    private void updateState(Thermostat t) {
+        boolean shouldUpdate = this.computeState(t);
+
+        if (shouldUpdate) {
+            thermostatRepository.save(t);
+            endpoint.queueDeviceUpdate(t, thermostatRepository.findUser(t.getId()));
+        }
+    }
+
+    public void updateStates() {
+        Iterable<Thermostat> ts = thermostatRepository.findAll();
+        ts.forEach(this::updateState);
+    }
+
+    public Optional<Thermostat> findById(Long thermostat, String username) {
+        Optional<Thermostat> t = thermostatRepository.findByIdAndUsername(thermostat, username);
+
+        if (t.isPresent()) {
+            Thermostat u = t.get();
+            populateMeasuredTemperature(u);
+            t = Optional.of(u);
+        }
+
+        return t;
+    }
+
+    private BigDecimal measureTemperature(final Thermostat thermostat) {
+        Optional<BigDecimal> average;
+
+        if (thermostat.isUseExternalSensors()) {
+            average = thermostatRepository.getAverageTemperature(thermostat.getRoomId());
+        } else {
+            return thermostat.getInternalSensorTemperature();
+        }
+
+        return average.orElse(null);
+    }
+
+    public void populateMeasuredTemperature(Thermostat thermostat) {
+        thermostat.setMeasuredTemperature(measureTemperature(thermostat));
+    }
+}