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Do not throw exception when no webcam in the system
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closes #29
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@sarxos
sarxos committed Feb 3, 2013
1 parent efe34b4 commit 1183329
Showing 1 changed file with 70 additions and 43 deletions.
113 changes: 70 additions & 43 deletions webcam-capture/src/main/java/com/github/sarxos/webcam/Webcam.java
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Original file line number Diff line number Diff line change
Expand Up @@ -17,14 +17,20 @@


/**
* Webcam class.
* Webcam class. It wraps webcam device obtained from webcam driver.
*
* @author Bartosz Firyn (bfiryn)
*/
public class Webcam {

/**
* Logger instance.
*/
private static final Logger LOG = LoggerFactory.getLogger(Webcam.class);

/**
* List of default drivers to search in classpath.
*/
// @formatter:off
private static final String[] DRIVERS_DEFAULT = new String[] {
"com.github.sarxos.webcam.ds.openimaj.OpenImajDriver",
Expand All @@ -34,12 +40,21 @@ public class Webcam {
// @formatter:on

private static final List<String> DRIVERS_LIST = new ArrayList<String>(Arrays.asList(DRIVERS_DEFAULT));

private static final List<Class<?>> DRIVERS_CLASS_LIST = new ArrayList<Class<?>>();

private static final List<WebcamDiscoveryListener> DISCOVERY_LISTENERS = Collections.synchronizedList(new ArrayList<WebcamDiscoveryListener>());

/**
* Shutdown hook to be executed when JVM exits gracefully.
*
* @author Bartosz Firyn (sarxos)
*/
private static final class ShutdownHook extends Thread {

/**
* Webcam instance to be disposed / closed.
*/
private Webcam webcam = null;

public ShutdownHook(Webcam webcam) {
Expand All @@ -55,8 +70,14 @@ public void run() {
}
}

/**
* Webcam driver (LtiCivil, JMF, FMJ, JQT, OpenCV, VLCj, etc).
*/
private static WebcamDriver driver = null;

/**
* Webcam discovery service.
*/
private static WebcamDiscoveryService discovery = null;

/**
Expand All @@ -69,26 +90,36 @@ public void run() {
*/
private List<WebcamListener> listeners = Collections.synchronizedList(new ArrayList<WebcamListener>());

/**
* List of custom resolution sizes supported by webcam instance.
*/
private List<Dimension> customSizes = new ArrayList<Dimension>();

/**
* Shutdown hook.
*/
private ShutdownHook hook = null;

/**
* Underlying webcam device.
*/
private WebcamDevice device = null;

/**
* Is webcam open?
*/
private volatile boolean open = false;
private volatile boolean disposed = false;

/**
* Timeout for devices discovery. By default this is set to 1 minute, but
* can be changed by appropriate static setter.
*
* @see Webcam#setDiscoveryTimeout(long)
* Is webcam already disposed?
*/
private static long timeout = 60000;
private volatile boolean disposed = false;

/**
* Webcam class.
*
* @param device - device to be used as webcam
* @throws IllegalArgumentException when argument is null
*/
protected Webcam(WebcamDevice device) {
if (device == null) {
Expand All @@ -108,10 +139,10 @@ private void ensureSize() {
Dimension[] sizes = device.getSizes();

if (sizes == null) {
throw new WebcamException("Sizes array from driver cannot be null!");
throw new WebcamException("Device error - sizes array from driver cannot be null!");
}
if (sizes.length == 0) {
throw new WebcamException("Sizes array from driver is empty, cannot choose image size");
throw new WebcamException("Device error - sizes array from driver cannot be empty");
}

device.setSize(sizes[0]);
Expand Down Expand Up @@ -318,11 +349,13 @@ public BufferedImage getImage() {
* @throws WebcamException when something is wrong
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static List<Webcam> getWebcams() {
public static List<Webcam> getWebcams() throws WebcamException {
try {
return getWebcams(timeout);
return getWebcams(Long.MAX_VALUE);
} catch (TimeoutException e) {
throw new WebcamException(e);
// this should never happen since user would have to wait 300000000
// years for it to occur
throw new RuntimeException(e);
}
}

Expand All @@ -335,7 +368,7 @@ public static List<Webcam> getWebcams() {
* @throws WebcamException when something is wrong
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static List<Webcam> getWebcams(long timeout) throws TimeoutException {
public static List<Webcam> getWebcams(long timeout) throws TimeoutException, WebcamException {
return getWebcams(timeout, TimeUnit.MILLISECONDS);
}

Expand All @@ -349,7 +382,7 @@ public static List<Webcam> getWebcams(long timeout) throws TimeoutException {
* @throws TimeoutException when timeout has been exceeded
* @throws WebcamException when something is wrong
*/
public static List<Webcam> getWebcams(long timeout, TimeUnit tunit) throws TimeoutException {
public static List<Webcam> getWebcams(long timeout, TimeUnit tunit) throws TimeoutException, WebcamException {

WebcamDiscoveryService discovery = getDiscoveryService();
List<Webcam> webcams = discovery.getWebcams(timeout, tunit);
Expand All @@ -365,14 +398,16 @@ public static List<Webcam> getWebcams(long timeout, TimeUnit tunit) throws Timeo
* Will discover and return first webcam available in the system.
*
* @return Default webcam (first from the list)
* @throws WebcamException if something is wrong
* @throws WebcamException if something is really wrong
* @see Webcam#getWebcams()
*/
public static Webcam getDefault() {
public static Webcam getDefault() throws WebcamException {
try {
return getDefault(timeout);
return getDefault(Long.MAX_VALUE);
} catch (TimeoutException e) {
throw new WebcamException(e);
// this should never happen since user would have to wait 300000000
// years for it to occur
throw new RuntimeException(e);
}
}

Expand All @@ -382,9 +417,10 @@ public static Webcam getDefault() {
* @param timeout the webcam discovery timeout (1 minute by default)
* @return Default webcam (first from the list)
* @throws TimeoutException when discovery timeout has been exceeded
* @throws WebcamException if something is really wrong
* @see Webcam#getWebcams(long)
*/
public static Webcam getDefault(long timeout) throws TimeoutException {
public static Webcam getDefault(long timeout) throws TimeoutException, WebcamException {
return getDefault(timeout, TimeUnit.MILLISECONDS);
}

Expand All @@ -395,9 +431,10 @@ public static Webcam getDefault(long timeout) throws TimeoutException {
* @param tunit the time unit
* @return Default webcam (first from the list)
* @throws TimeoutException when discovery timeout has been exceeded
* @throws WebcamException if something is really wrong
* @see Webcam#getWebcams(long, TimeUnit)
*/
public static Webcam getDefault(long timeout, TimeUnit tunit) throws TimeoutException {
public static Webcam getDefault(long timeout, TimeUnit tunit) throws TimeoutException, WebcamException {

if (timeout < 0) {
throw new IllegalArgumentException("Timeout cannot be negative");
Expand All @@ -407,11 +444,14 @@ public static Webcam getDefault(long timeout, TimeUnit tunit) throws TimeoutExce
}

List<Webcam> webcams = getWebcams(timeout, tunit);
if (webcams.isEmpty()) {
throw new WebcamException("No webcam available in the system");

if (!webcams.isEmpty()) {
return webcams.get(0);
}

return webcams.get(0);
LOG.warn("No webcam has been detected!");

return null;
}

/**
Expand All @@ -434,6 +474,7 @@ public String toString() {
* Add webcam listener.
*
* @param l the listener to be added
* @throws IllegalArgumentException when argument is null
*/
public boolean addWebcamListener(WebcamListener l) {
if (l == null) {
Expand Down Expand Up @@ -485,7 +526,8 @@ public static WebcamDriver getDriver() {
* <br>
* <b>This method is not thread-safe!</b>
*
* @param driver new video driver to use (e.g. Civil, JFM, FMJ, QTJ, etc)
* @param driver new webcam driver to be used (e.g. LtiCivil, JFM, FMJ, QTJ)
* @throws IllegalArgumentException when argument is null
*/
public static void setDriver(WebcamDriver driver) {
if (driver == null) {
Expand All @@ -503,6 +545,7 @@ public static void setDriver(WebcamDriver driver) {
* <b>This method is not thread-safe!</b>
*
* @param driver new video driver class to use
* @throws IllegalArgumentException when argument is null
*/
public static void setDriver(Class<? extends WebcamDriver> driverClass) {

Expand Down Expand Up @@ -544,6 +587,7 @@ public static void resetDriver() {
* Register new webcam video driver.
*
* @param clazz webcam video driver class
* @throws IllegalArgumentException when argument is null
*/
public static void registerDriver(Class<? extends WebcamDriver> clazz) {
if (clazz == null) {
Expand All @@ -557,6 +601,7 @@ public static void registerDriver(Class<? extends WebcamDriver> clazz) {
* Register new webcam video driver.
*
* @param clazzName webcam video driver class name
* @throws IllegalArgumentException when argument is null
*/
public static void registerDriver(String clazzName) {
if (clazzName == null) {
Expand Down Expand Up @@ -645,6 +690,7 @@ public static boolean isHandleTermSignal() {
*
* @param l the listener to be added
* @return True, if listeners list size has been changed, false otherwise
* @throws IllegalArgumentException when argument is null
*/
public static boolean addDiscoveryListener(WebcamDiscoveryListener l) {
if (l == null) {
Expand Down Expand Up @@ -678,23 +724,4 @@ public static WebcamDiscoveryService getDiscoveryService() {
}
return discovery;
}

/**
* Set new devices discovery timeout. By default this is set to 1 minute
* (60000 milliseconds).
*
* @param timeout the new discovery timeout in milliseconds
*/
public static void setDiscoveryTimeout(long timeout) {
Webcam.timeout = timeout;
}

/**
* Return default webcam discovery timeout in milliseconds.
*
* @return Timeout in milliseconds
*/
public static long getDiscoveryTimeout() {
return Webcam.timeout;
}
}

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