trusty (3) UR::Context::Transaction.3pm.gz

NAME

       UR::Context::Transaction - API for software transactions

SYNOPSIS

         my $o = Some::Obj->create(foo => 1);
         print "o's foo is ",$o->foo,"\n";  # prints 1

         my $t = UR::Context::Transaction->begin();

         $o->foo(4);

         print "In transaction, o's foo is ",$o->foo,"\n";  # prints 4

         if (&should_we_commit()) {
             $t->commit();
             print "Transaction committed, o's foo is ",$o->foo,"\n";  # prints 4

         } else {
             $t->rollback();
             print "Transaction rollback, o's foo is ",$o->foo,"\n";  # prints 1
         }

DESCRIPTION

       UR::Context::Transaction instances represent in-memory transactions as a diff of the contents of the
       object cache in the Process context.  Transactions are nestable.  Their instances exist in the object
       cache and  are subject to the same scoping rules as other UR-based objects, meaning that they do not
       disappear mearly because the lexical variable they're assigned to goes out of scope.  They must be
       explicitly disposed of via the commit or rollback methods.

INHERITANCE

       UR::Context::Transaction is a subclass of UR::Context

CONSTRUCTOR

       begin
             $t = UR::Context::Transaction->begin();

           Creates a new software transaction context to track changes to UR-based objects.  As all activity to
           objects occurs in some kind of transaction context, the newly created transaction exists within
           whatever context was current before the call to begin().

METHODS

       commit
             $t->commit();

           Causes all objects with changes to save those changes back to the underlying context.

       rollback
             $t->rollback();

           Causes all objects with changes to have those changes reverted to their state when the transaction
           began.  Classes with properties whose meta-property is_transactional => 0 are not tracked within a
           transaction and will not be reverted.

       delete
             $t->delete();

           delete() is a synomym for rollback

       has_changes
             $bool = $t->has_changes();

           Returns true if any UR-based objects have changes within the transaction.

       get_changes
             @changes = $t->get_changes();

           Return a list or UR::Change objects representing changes within the transaction.

CLASS METHODS

       execute
             $retval = UR::Context::Transaction->execute($coderef);

           Executes the coderef with no arguments, within an eval and a software transaction.  If the coderef
           returns true, the transaction is committed.  If it returns false, the transaction is rolled back.
           Finally the coderef's return value is returned to the caller.

           If the coderef throws an exception, it will be caught, the transaction rolled back, and the exception
           will be re-thrown with die().

       execute_and_rollback
             UR::Context::Transaction->execute_and_rollback($coderef);

           Executes the coderef with no arguments, within an eval and a software transaction.  Reguardless of
           the return value of the coderef, the transaction will be rolled back.

           If the coderef throws an exception, it will be caught, the transaction rolled back, and the exception
           will be re-thrown with die().

SEE ALSO

       UR::Context