Using the dummy camera with no network results in a delay during preinitialize() and initialize()

[cxbrooks]

Note: the issue was created automatically with bugzilla2github tool

Original bug ID: BZ#14
From: @cxbrooks
Reported version: unspecified
CC: accessors-devel@terraswarm.org

[cxbrooks]

Edward wrote:

"The Random demo, if I select the dummy camera and have wifi turned off
(not sure whether that is relevant) takes a very long time to
preinitialize and initialize. Not sure why... Maybe related to the
getResource() issues that you have encountered."

Disconnecting from the network and then running

java -classpath '.:./lib/*' ptolemy.vergil.VergilApplication ./ptolemy/actor/lib/jjs/modules/imageFilters/demo/ImageFilters/Random.xml

and then running jstack on the java pid shows that the process is hanging while trying to get discover the camera:

Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.101-b13 mixed mode):

"webcam-discovery-service" BZ#35 daemon prio=1 os_prio=31 tid=0x00007fff4db24800 nid=0x10c2b in Object.wait() [0x000070000558d000]
java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at com.github.sarxos.webcam.WebcamDiscoveryService.run(WebcamDiscoveryService.java:257)
- locked <0x00000007792426e8> (a java.lang.Object)
at java.lang.Thread.run(Thread.java:745)

"Random" BZ#30 prio=1 os_prio=31 tid=0x00007fff4e8a3000 nid=0x13a77 in Object.wait() [0x00007000063ef000]
java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Thread.join(Thread.java:1245)
- locked <0x0000000779242570> (a java.lang.Thread)
at java.lang.Thread.join(Thread.java:1319)
at com.github.sarxos.webcam.WebcamDiscoveryService.stop(WebcamDiscoveryService.java:314)
at com.github.sarxos.webcam.WebcamDiscoveryService.shutdown(WebcamDiscoveryService.java:382)
at com.github.sarxos.webcam.Webcam.resetDriver(Webcam.java:1036)
at com.github.sarxos.webcam.Webcam.setDriver(Webcam.java:992)
at ptolemy.actor.lib.jjs.modules.cameras.CameraHelper.(CameraHelper.java:136)
at java.lang.invoke.LambdaForm$DMH/1901118561.newInvokeSpecial_L3_L(LambdaForm$DMH)
at java.lang.invoke.LambdaForm$BMH/1472481487.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$MH/2069048820.exactInvoker(LambdaForm$MH)
at java.lang.invoke.LambdaForm$MH/1472119832.linkToCallSite(LambdaForm$MH)
at jdk.nashorn.internal.scripts.Script$Recompilation$499$4590A$require.L:1$Camera(/Users/cxh/src/ptII11.0.devel/ptolemy/actor/lib/jjs/ext
ernal/require.js#401:30:109)
at java.lang.invoke.LambdaForm$DMH/895328852.invokeStatic_L3_L(LambdaForm$DMH)
at java.lang.invoke.LambdaForm$BMH/1947857091.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$BMH/1653494421.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$MH/689815922.exactInvoker(LambdaForm$MH)
at java.lang.invoke.LambdaForm$MH/736147259.linkToCallSite(LambdaForm$MH)
at jdk.nashorn.internal.scripts.Script$Recompilation$487$3275$^function_.L:1$setup(:83)
at java.lang.invoke.LambdaForm$DMH/723074861.invokeStatic_LL_L(LambdaForm$DMH)
at java.lang.invoke.LambdaForm$BMH/1804661649.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$MH/128853523.exactInvoker(LambdaForm$MH)
at java.lang.invoke.LambdaForm$MH/1970553451.linkToCallSite(LambdaForm$MH)
at jdk.nashorn.internal.scripts.Script$Recompilation$477$18417AAAAAA$require.L:1$Accessor(/Users/cxh/src/ptII11.0.devel/ptolemy/actor/lib
/jjs/external/require.js#401:30:586)
at java.lang.invoke.LambdaForm$DMH/951007336.invokeStatic_L8_L(LambdaForm$DMH)
at java.lang.invoke.LambdaForm$BMH/1525193662.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$BMH/177973284.reinvoke(LambdaForm$BMH)
at java.lang.invoke.LambdaForm$MH/1118239097.exactInvoker(LambdaForm$MH)
at java.lang.invoke.LambdaForm$MH/837155914.linkToCallSite(LambdaForm$MH)
at jdk.nashorn.internal.scripts.Script$Recompilation$476$2615AA$^eval_.evaluateCode(:88)
at java.lang.invoke.LambdaForm$DMH/603742814.invokeStatic_L4_L(LambdaForm$DMH)
at java.lang.invoke.LambdaForm$MH/829824402.invokeExact_MT(LambdaForm$MH)
at jdk.nashorn.internal.runtime.ScriptFunctionData.invoke(ScriptFunctionData.java:641)
at jdk.nashorn.internal.runtime.ScriptFunction.invoke(ScriptFunction.java:494)
at jdk.nashorn.internal.runtime.ScriptRuntime.apply(ScriptRuntime.java:393)
at jdk.nashorn.api.scripting.ScriptObjectMirror.callMember(ScriptObjectMirror.java:199)
at jdk.nashorn.api.scripting.NashornScriptEngine.invokeImpl(NashornScriptEngine.java:383)

---end---

The sources are at https://github.com/sarxos/webcam-capture/blob/master/webcam-capture/src/main/java/com/github/sarxos/webcam/WebcamDiscoveryService.java

This looks like a bug the Webcam package, we would need to track it down there.