-runstartlevel ( order | begin | step )*

After a resolve the resolver calculates a number of resources that are mapped to bundles. This mapping can include ordering and assigned startlevels. The basic instruction that parameterizes this is -runstartlevel.

Default behavior when not set

If -runstartlevel is not set the set of -runbundles will be sorted by name and version after which it is merged with the existing -runbundles. Setting the -runstartlevel makes it possible to let bnd assign startlevels based on different ordering strategies.

Syntax

This instruction has the following syntax:

-runstartlevel      ::= runstartlevel ( ',' runstartlevel )
runstartlevel       ::  order | begin | step
order               ::= 'order=' ORDER
ORDER               ::= 
        'leastdependenciesfirst' 
    |   'leastdependencieslast'
    |   'random'
    |   'sortbynameversion'
    |   'mergesortbynameversion'
begin               ::= 'begin=' NUMBER
step                ::= 'step=' NUMBER

The final -runstartlevel flattens the properties so that the last of each of order, begin, or step will be used.

Order Types

The value of order can take on the following values:

• mergesortbynameversion – Ordering by name (and version) and then merging was the original behavior. This is therefore the default.
• sortbynameversion – For completeness, this option orders the bundles by name and version and then assigns a startlevel.
• random – Use a random ordering. The ordering uses an algorithm that is based on the random number generator and should therefore be different on each run.
• leastdependenciesfirst – Sort the resources topologically and place the resources with the least dependencies first.
• leastdependencieslast – Sort the resources topologically and place the resources with the least dependencies last.

The topological sorting algorithm is based on Tarjan. It can handle cyclic dependencies well. However, cyclic dependencies make the ordering not perfect.

Startlevels

After the resources have been resolved they are sorted according to the order. If the begin attribute is set and higher than 0, the resources will be assigned a startlevel that starts at the given value. By default, the step for each bundle is 10. (A lesson taught to us by BASIC) The step can be overridden by setting the step value.

If the begin value is not set, or it is set to a value < 1, then no startlevel attribute is added. However, the order of the -runbundles will be in the specified order. In most cases, this is then some kind of natural ordering since launchers start these

If you set the step to 0 then all bundles will be assigned the same startlevel. However, the -runbundles has the proper order.

Example

-runstartlevel: \
    order = leastdependenciesfirst, \
    begin = 1000, \
    step  =    1

After resolving, this can generate:

-runbundles: \
	org.apache.felix.configadmin;version='[1.8.8,1.8.9)';startlevel=1000,\
	org.apache.felix.http.jetty;version='[3.2.0,3.2.1);startlevel=1001',\
	org.apache.felix.http.servlet-api;version='[1.1.2,1.1.3);startlevel=1002',\
	...
	osgi.enroute.twitter.bootstrap.webresource;version='[3.3.5,3.3.6);startlevel=1019',\
	osgi.enroute.web.simple.provider;version='[2.1.0,2.1.1);startlevel=1020'