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CaptureDeviceManager.java
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CaptureDeviceManager.java
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package javax.media;
import java.io.*;
import java.lang.reflect.*;
import java.util.*;
import java.util.logging.*;
import net.sf.fmj.utility.*;
/**
* Standard JMF class -- see <a href=
* "http://java.sun.com/products/java-media/jmf/2.1.1/apidocs/javax/media/CaptureDeviceManager.html"
* target="_blank">this class in the JMF Javadoc</a>. Coding complete.
*
* @author Ken Larson
*
*/
public class CaptureDeviceManager
{
// It looks like Sun's implementation might delegate this (via reflection)
// to javax.media.cdm.CaptureDeviceManager, which has synchronized methods.
// We'll do the same, to ensure maximum compatibility, although the reasons
// for this technique are not clear.
// I suspect that they did this to make it easier to ship
// "performance packs" for different operating systems, which might
// have different implementations for these various managers.
// TODO: make this class have the same signature as Sun's.
private static final Logger logger = LoggerSingleton.logger;
private static Class<?> implClass;
private static Method getDeviceMethod;
private static Method getDeviceListMethod;
private static Method addDeviceMethod;
private static Method removeDeviceMethod;
private static Method commitMethod;
public static boolean addDevice(CaptureDeviceInfo newDevice)
{
if (!init())
return false;
return ((Boolean) callImpl(addDeviceMethod, new Object[] { newDevice }))
.booleanValue();
}
private static Object callImpl(Method method, Object[] args)
{
try
{
return method.invoke(null, args);
} catch (IllegalArgumentException e)
{
logger.log(Level.WARNING, "" + e, e);
return null;
} catch (IllegalAccessException e)
{
logger.log(Level.WARNING, "" + e, e);
return null;
} catch (InvocationTargetException e)
{
logger.log(Level.WARNING, "" + e, e);
return null;
}
}
public static void commit() throws IOException
{
if (!init())
return;
final Method method = commitMethod;
final Object[] args = new Object[] {};
// do this one explicitly so we can catch and re-throw IOException.
try
{
method.invoke(null, args);
} catch (IllegalArgumentException e)
{
logger.log(Level.WARNING, "" + e, e);
return;
} catch (IllegalAccessException e)
{
logger.log(Level.WARNING, "" + e, e);
return;
} catch (InvocationTargetException e)
{
if (e.getCause() instanceof IOException)
throw (IOException) e.getCause();
logger.log(Level.WARNING, "" + e, e);
return;
}
}
public static CaptureDeviceInfo getDevice(String deviceName)
{
if (!init())
return null;
return (CaptureDeviceInfo) callImpl(getDeviceMethod,
new Object[] { deviceName });
}
public static Vector getDeviceList(Format format)
{
if (!init())
return null;
return (Vector) callImpl(getDeviceListMethod, new Object[] { format });
}
private static Method getStaticMethodOnImplClass(String name,
Class<?>[] args, Class<?> returnType) throws Exception
{
final Method m = implClass.getMethod(name, args);
if (m.getReturnType() != returnType)
throw new Exception("Expected return type of method " + name
+ " to be " + returnType + ", was " + m.getReturnType());
if (!Modifier.isStatic(m.getModifiers()))
throw new Exception("Expected method " + name + " to be static");
return m;
}
private static synchronized boolean init()
{
if (implClass != null)
return true; // already initialized;
try
{
implClass = Class.forName("javax.media.cdm.CaptureDeviceManager");
if (!(CaptureDeviceManager.class.isAssignableFrom(implClass)))
throw new Exception(
"javax.media.cdm.CaptureDeviceManager not subclass of "
+ CaptureDeviceManager.class.getName());
getDeviceMethod = getStaticMethodOnImplClass("getDevice",
new Class[] { String.class }, CaptureDeviceInfo.class);
getDeviceListMethod = getStaticMethodOnImplClass("getDeviceList",
new Class[] { Format.class }, Vector.class);
addDeviceMethod = getStaticMethodOnImplClass("addDevice",
new Class[] { CaptureDeviceInfo.class }, boolean.class);
removeDeviceMethod = getStaticMethodOnImplClass("removeDevice",
new Class[] { CaptureDeviceInfo.class }, boolean.class);
commitMethod = getStaticMethodOnImplClass("commit", new Class[] {},
void.class);
} catch (Exception e)
{
implClass = null;
logger.log(Level.WARNING, "" + e, e);
return false;
}
return true;
}
public static boolean removeDevice(CaptureDeviceInfo device)
{
if (!init())
return false;
return ((Boolean) callImpl(removeDeviceMethod, new Object[] { device }))
.booleanValue();
}
public CaptureDeviceManager()
{
}
}