Dmitry, I support your idea to clean up VM properties code. I do not like the current state of the implementation too.
But I have a couple of questions: 1) Who is responsible to deallocate memory for hidden properties? E.g. the same "const char*" value could be allocated with malloc or new or could be the static value. 2) By adding hidden properties you introduce a new style of communication between components. Why limit hidden properties with "const char*" values? Are there any problems with void* ? On 10/10/06, Geir Magnusson Jr. <[EMAIL PROTECTED]> wrote:
Inline Dmitry Yershov wrote: [snip] > > VM properties proposal > ====================== > > The general purpose of VM Properties subcomponent is to provide > centralized access to a common properties table. A property is meant > as a pair of <key> and <value>. The properties stored in VM Properties > table represent configuration settings for a separate component (such > as VMCore, GC, JIT etc) or for the whole system. Another use case for > the properties is communication between different components. > > Requirements > ============ > > 1) The <key> and <value> are represented as string (i.e. char*). and I propose that on each operation, a copy is made, so that the caller frees the string that they got or gave. > 2) NULL values are allowed. > 3) VM Properties subcomponent exports its interface as part of VM > Core. > 4) There are two kind of properties > * Public properties are properties visible both to all VM > components and to Java applications (by means of > java.lang.System.getProperties() method). > * Hidden properties are used for VM components communication > only, not accessible from Java side. > 5) There is a way to set hidden properties through non standard > command line option ( -XDefine<key>=<value>). > 6) There is a way to get a list of defined properties which keys > begin with a particular prefix. > 7) Properties table should be thread safe. > > VM Properties usage scenario > ============================ > > Components can define properties and lookup them by name. When > setting the property it can be marked either public or hidden. A > property should be marked as hidden if it is intended internal usage > only. Public properties are supposed to be visible from Java side also. > In the same time it is possible to obtain a list of all public properties > to pass them to Java side. > > Defined Interface functions > =========================== > > void set_property(const char * key, const char * value) - Sets the > public property. NULL values are supported. > > void set_hidden_property(const char * key, const char * value) - Sets > the hidden property. NULL values are supported. > > const char * get_property(const char * key) - Returns the value of the > property if it has been set by set_property function. Otherwise returns > NULL. > > const char * get_hidden_property(const char * key) - Returns the value > of the property if it has been set by set_hidden_property function. > Otherwise returns NULL. > > bool is_property_set(const char * key, bool hidden) - Checks if the > property is set. > > void unset_property(const char * key, bool hidden) - Unsets the property. > > char * * get_public_property_keys() - Returns an array of keys for all > public properties set. > > char * * get_properties_staring_with(const char * prefix, bool hidden) - > Returns an array of keys for all properties set whose keys start with > the prefix specified. 1) if this is a C++ class, lets drop the word 'property' 2) Don't hardcode 'hidden' into the API, as we may have other types down the road. Make it an argument set( key, val, type ) get( key, type ) is_set(key) unset(key) get_keys(type) .... > > > ------------------------------------------------------------------------ > > --------------------------------------------------------------------- > Terms of use : http://incubator.apache.org/harmony/mailing.html > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
-- Mikhail Fursov
