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https://issues.apache.org/jira/browse/KARAF-5757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16479261#comment-16479261
]
Guillaume Nodet commented on KARAF-5757:
----------------------------------------
The 3 gogo fixes lead to the following now, it's a bit easier to read, though
not awesome. Not sure what to improve.
{code}
create-tracker = {
trackingContext = $1 ; trackedClass = $2 ; serviceAdded = $3 ;
serviceRemoved = $4
handler = {
proxy = $1 ; method = $2 ; arguments = $3
name = ($method name)
# echo "Invoking $name"
if { $name equals "addingService" } \
then {
ref = ${arguments[0]}
svc = ($.context getService $ref)
$serviceAdded execute $.commandSession [ $svc ]
$svc
} elif { $name equals "removedService" } \
then {
ref = ${arguments[0]} ; svc = ${arguments[1]}
$serviceRemoved execute $.commandSession [ $svc ]
$.context ungetService $ref
}
}
# create handler
shellClassLoader = ($.commandSession classLoader)
customizerClass = ($shellClassLoader loadClass
org.osgi.util.tracker.ServiceTrackerCustomizer)
proxyClass = ($shellClassLoader loadClass java.lang.reflect.Proxy)
customizer = ($proxyClass newProxyInstance $shellClassLoader [
$customizerClass ] $handler)
# create tracker
if { "java.lang.Class" equals ($trackedClass class) } \
then {
trackedClass = ($trackedClass name)
}
tracker = (new org.osgi.util.tracker.ServiceTracker $trackingContext
$trackedClass $customizer)
$tracker
}
tracker = (create-tracker $.context "org.osgi.service.cm.ManagedService" { s =
(($1 class) toString); echo "service-added $s" } { s = (($1 class) toString);
echo "service-removed $s" })
$tracker open true
{code}
> Improve shell reflection capabilities
> -------------------------------------
>
> Key: KARAF-5757
> URL: https://issues.apache.org/jira/browse/KARAF-5757
> Project: Karaf
> Issue Type: New Feature
> Reporter: Guillaume Nodet
> Priority: Major
> Fix For: 4.3.0
>
>
> Writing karaf scripts can be very tedious when dealing with reflection and
> classes.
> It needs to be simplified a lot.
> Below is a script definining a command to create a service tracker:
> {code:java}
> create-tracker = {
> trackingContext = $1
> trackedClass = $2
> serviceAdded = $3
> serviceRemoved = $4
> shellClassLoader = (($.session class) getClassLoader)
> arrayClass = ($shellClassLoader loadClass java.lang.reflect.Array)
> handler = {
> proxy = $1
> method = $2
> arguments = $3
> name = ($method name)
> # echo "Invoking $name"
> if { $name equals "addingService" } \
> then {
> ref = ($arrayClass get $arguments 0)
> svc = ($.context getService $ref)
> $serviceAdded execute $.commandSession [ $svc ]
> $svc
> } elif { $name equals "removedService" } \
> then {
> ref = ($arrayClass get $arguments 0)
> svc = ($arrayClass get $arguments 1)
> $serviceRemoved execute $.commandSession [ $svc ]
> $.context ungetService $ref
> }
> }
> # create handler
> customizerClass = ($shellClassLoader loadClass
> org.osgi.util.tracker.ServiceTrackerCustomizer)
> array = ([ $customizerClass ] toArray ($arrayClass newInstance
> "java.lang.Class" 1))
> proxyClass = ($shellClassLoader loadClass java.lang.reflect.Proxy)
> customizer = ($proxyClass newProxyInstance $shellClassLoader $array
> $handler)
> # create tracker
> trackerClass = ($shellClassLoader loadClass
> org.osgi.util.tracker.ServiceTracker)
> constructor = ($trackerClass constructor
> org.osgi.framework.BundleContext java.lang.String
> org.osgi.util.tracker.ServiceTrackerCustomizer)
> if { "java.lang.Class" equals ($trackedClass class) } \
> then {
> trackedClass = ($trackedClass name)
> }
> tracker = ($constructor newInstance $trackingContext $trackedClass
> $customizer)
> $tracker
> }
> tracker = (create-tracker $.context "org.osgi.service.cm.ManagedService" { s
> = (($1 class) toString); echo "service-added $s" } { s = (($1 class)
> toString); echo "service-removed $s" })
> $tracker open true
> {code}
> Also, the Gogo Runtime expander does not support subscripts in java arrays.
> It has to be a {{List}}. This should be fixed, see
> [https://github.com/apache/felix/blob/trunk/gogo/runtime/src/main/java/org/apache/felix/gogo/runtime/Expander.java#L1483].
> Conversion from list to array would be needed too.
> In order to be more user-friendly, we need helper methods to define a context
> class loader, load classes (the String -> Class conversion needs to leverage
> it).
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