The class THREAD is used to create, initialize - and destroy threads and to pass commands to these + and destroy threads and to pass commands to these threads. It is designed in a way to create threads lazyly such that thread definitions can be included - in the modules directory of the AOLserver and + in the modules directory of the AOLserver and therefore be part of the AOLserver blueprints. - When an instance of THREAD is created (e.g. t1), + When an instance of THREAD is created (e.g. t1), an init-command is provided. e.g.:
::xotcl::THREAD create t1 {
@@ -24,32 +24,32 @@
Commands are sent to the thread via the
"do" method, which returns the result of the
- command evaluated in the specified thread.
- When the first command is sent to a
+ command evaluated in the specified thread.
+ When the first command is sent to a
non-initialized thread, such as
set x [t1 do c1 ++] -- the actual thread is created and the thread + + the actual thread is created and the thread ID is remembered in a tsv array. When a THREAD object is destroyed, the associated - thread is terminated as well. - + thread is terminated as well. + Notice that according to the aol-server behavior it is possible to create **persistent threads** (when the thread object is created during startup and provided to all request threads through the blueprint), or to create **volatile threads** that are created during a request and which are deleted when the thread cleanup - is called after some timeout. Volatile threads can + is called after some timeout. Volatile threads can shared as well (when different request-threads - create the same-named thread objects) and can + create the same-named thread objects) and can be used for caching proposes. Flushing the cache can be done in the thread's exitHandler. - + The Proxy class can be used to simplify - the interaction with a thread and to + the interaction with a thread and to hide the fact, that certain classes/objects are part of a thread. The following command creates a Proxy for an object c1 in thread t1. @@ -58,27 +58,27 @@ ::xotcl::THREAD::Proxy c1 -attach t1 set x [c1 ++] - The Proxy forwards all commands to the - attached thread except the methods attach, filter, - detachAll and destroy. The attach method can be used - to reattach a proxy instance to a different thread, such as -
+ The Proxy forwards all commands to the + attached thread except the methods attach, filter, + detachAll and destroy. The attach method can be used + to reattach a proxy instance to a different thread, such as +c1 attach t2A proxy can be (temporarily) detachted from a thread viac1 filter ""- Later forwarding to the thread can be re-enabled via + Later forwarding to the thread can be re-enabled viac1 filter forward- When a proxy is attached to a thread and + When a proxy is attached to a thread and receives a destroy command, both the proxy - and the corresponding object in the thread + and the corresponding object in the thread are deleted. If only the proxy object is to be destroyed, the proxy must be detachted at first. - The class method detatchAll is provided to detach + The class method detatchAll is provided to detach all proxies from their objects. @author Gustaf Neumann @@ -122,9 +122,9 @@ if {![ns_ictl epoch]} { #ns_log notice "--THREAD init [self] no epoch" - # We are during initialization. For some unknown reasons, XOTcl + # We are during initialization. For some unknown reasons, XOTcl # is not available in newly created threads, so we have to care for it. - # We need only a partial initialization, to allow the exit handler + # We need only a partial initialization, to allow the exit handler # to be defined. set :initcmd { package req XOTcl @@ -141,14 +141,14 @@ append :initcmd \n\ [list set ::xotcl::currentScript [info script]] \n\ [list set ::xotcl::currentThread [self]] \n\ - $cmd + $cmd set :mutex [ns_mutex create] ns_log notice "mutex ${:mutex} created" next } ::xotcl::THREAD ad_proc -private recreate {obj args} { - this method catches recreation of THREADs in worker threads + this method catches recreation of THREADs in worker threads it reinitializes the thread according to the new definition. } { :log "recreating [self] $obj, tid [$obj exists tid]" @@ -166,7 +166,7 @@ ::xotcl::THREAD instproc destroy {} { :log "destroy called" - if {![:persistent] && + if {![:persistent] && [nsv_exists [self class] [self]]} { set tid [nsv_get [self class] [self]] set refcount [::thread::release $tid] @@ -216,8 +216,8 @@ if {[:lightweight]} { } elseif {![ns_ictl epoch]} { #ns_log notice "--THREAD send [self] no epoch" - # We are during initialization. For some unknown reasons, XOTcl - # is not available in newly created threads, so we have to care + # We are during initialization. For some unknown reasons, XOTcl + # is not available in newly created threads, so we have to care # for full initialization, including xotcl blueprint. _ns_savenamespaces set initcmd [ns_ictl get] @@ -230,13 +230,19 @@ } } } else { - # target thread is already up and running + # + # Target thread is already up and running. + # set tid [nsv_get [self class] [self]] } if {![info exists :tid]} { - # this is the first call + # + # This is the first call. + # if {![:persistent] && ![info exists :recreate]} { - # for a shared thread, we do ref-counting through preserve + # + # For a shared thread, we do ref-counting through preserve. + # set tid [nsv_get [self class] [self]] :log "THREAD::PRESERVE must preserve for sharing request-thread [pid] tid $tid" ::thread::preserve $tid @@ -251,24 +257,26 @@ } } -# create a sample persistent thread that can be acessed -# via request threads +# +# Create a sample persistent thread that can be acessed +# via request threads. +# #::xotcl::THREAD create t0 { # Class create Counter -parameter {{value 1}} # Counter instproc ++ {} {incr :value} -# +# # Counter create c1 # Counter create c2 #} -persistent 1 # ################## forwarding proxy ################## -# Class create ::xotcl::THREAD::Proxy -parameter {attach} +# Class create ::xotcl::THREAD::Proxy -parameter {attach} # ::xotcl::THREAD::Proxy configure \ # -instproc forward args { # set cp [self calledproc] # if { $cp eq "attach" -# || $cp eq "filter" +# || $cp eq "filter" # || $cp eq "detachAll"} { # next # } elseif {$cp eq "destroy"} { @@ -285,11 +293,11 @@ # foreach i [:info instances] {$i filter ""} # } +# +# Sample Thread client routine, calls a same named object in the +# server thread. Thread clients should be created in an connection +# thread dynamically to avoid name clashes in the blueprint. -# sample Thread client routine, calls a same named object in the server thread -# a thread client should be created in an connection thread dynamically to -# avoid name clashes in the blueprint. - Class create ::xotcl::THREAD::Client -parameter {server {serverobj [self]}} ::xotcl::THREAD::Client instproc do args { [:server] do [:serverobj] {*}$args