IBM BPM, V8.0.1, All platforms > Programming IBM BPM > Developing client applications for BPEL processes and tasks > Queries on BPEL process and task data > Business Process Choreographer EJB query API > Examples of the query and queryAll methods

Example: Querying tasks in the ready state

This example shows how to use the query method to retrieve tasks that the logged-on user can work with.

John Smith wants to get a list of the tasks that have been assigned to him. For a user to be able to work on a task, the task must be in the ready state. The logged-on user must also have a potential owner work item for the task. The following code snippet shows the query method call for this query:

query( "DISTINCT TASK.TKIID", 
           "TASK.KIND IN ( TASK.KIND.KIND_HUMAN, TASK.KIND.KIND_PARTICIPATING ) 
             AND " +  
           "TASK.STATE = TASK.STATE.STATE_READY AND " +  
           "WORK_ITEM.REASON = WORK_ITEM.REASON.REASON_POTENTIAL_OWNER", 
            (String)null, (String)null, (Integer)null, (TimeZone)null )

The following actions are taken when the SQL SELECT statement is generated:

• A condition for access control is added to the where clause. This example assumes that group work items are not enabled.
• Constants, such as TASK.STATE.STATE_READY, are replaced by their numeric values.

• A FROM clause and join conditions are added.

The following code snippet shows the SQL statement that is generated from the API query:

SELECT DISTINCT TASK.TKIID
   FROM   TASK TA, WORK_ITEM WI,  
   WHERE  WI.OBJECT_ID = TA.TKIID
   AND    TA.KIND IN ( 101, 105 )       
   AND    TA.STATE = 2   
   AND    WI.REASON = 1           
   AND  ( WI.OWNER_ID = 'JohnSmith' OR WI.OWNER_ID = null AND  WI.EVERYBODY = true )
     

To restrict the API query to tasks for a specific process, for example, sampleProcess, the query looks as follows:

query( "DISTINCT TASK.TKIID", 
           "PROCESS_TEMPLATE.NAME = 'sampleProcess' AND "+
           "TASK.KIND IN ( TASK.KIND.KIND_HUMAN, TASK.KIND.KIND_PARTICIPATING ) 
             AND " +  
           "TASK.STATE = TASK.STATE.STATE_READY AND " +  
           "WORK_ITEM.REASON = WORK_ITEM.REASON.REASON_POTENTIAL_OWNER", 
            (String)null, (String)null, (Integer)null, (TimeZone)null )

Examples of the query and queryAll methods