org.enhydra.shark.api.common

Common Shark package.

Contains interfaces and exceptions used in both client-side and internal interfaces.

Expirience has learned us that it's not that easy to build any usefull expression to be used in xxIterators. Since Shark supports BeanShell and JavaScript, making expressions starts to be even more complicated once you start to use string literals. Also, reading and debugging of such expression might turn into very tedious task. On the other side OMG (or at least the way we read it) explicitely says set_expression method takes String as parameter, and there's no escape.

ExpressionBuilder and it's extending interfaces/classes serves the intention to ease this task, although there is another benefit - it allows us to prepare such expressions xxIterator can execute directly against database, thus improving the performance.

The old style building (and setting) expressions for iterators diplayed in the code snippet bellow, quite efficiently hides the actual expression.

   ExecutionAdministration eAdmin=Shark.getInstance().getAdminInterface().getExecutionAdministration();
   eAdmin.connect("user","secret","","");

   WfProcessMgrIterator pmi=eAdmin.et_iterator_processmgr();
   // - old style building expression
   query="packageId.equals(\"test\") && enabled.booleanValue()";
   // - old style building expression
   pmi.set_query_expression(query);
   WfProcessMgr[] procs=pmi.get_next_n_sequence(0);

Our intention is to expose the main properties through ExpressionBuilders, allowing the code to be easier to write, more importantly easier to read and maintain.

   ExecutionAdministration eAdmin=Shark.getInstance().getAdminInterface().getExecutionAdministration();
   eAdmin.connect("user","secret","","");

   WfProcessMgrIterator pmi=eAdmin.et_iterator_processmgr();
   // - new style building expression
   ProcessMgrIteratorExpressionBuilder eb = Shark.getInstance()
         .getExpressionBuilderManager()
         .getProcessMgrIteratorExpressionBuilder();
   eb.addPackageIdEquals("test")
     .and()
     .addIsEnabled()
     .setOrderByName(ExpressionBuilder.ORDER_DESCENDING);
   // - new style building expression
   pmi.set_query_expression(eb.toExpression());
   WfProcessMgr[] procs=pmi.get_next_n_sequence(0);