ITaskQueryService的使用方法，来自官方API

oracle.bpel.services.workflow.query
Interface ITaskQueryService

http://docs.oracle.com/cd/E23943_01/apirefs.1111/e10660/oracle/bpel/services/workflow/query/ITaskQueryService.html

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public interface ITaskQueryService

 This class provides a programmatic means for retrieving tasks, task details, etc
 
 A typical usage would be as follows:
  1. Use an authentication method to authenticate a user and obtain a context
  2. Use the context and a task list method to retrieve tasks that match some filter criterion
  3. Use the context and a task details method to drill down on a task in the list (retrieve task details
        and actions that can be performed on the task)
  4. Use task service, to perform operations on the task
  
 A sample code fragment that shows the usage in the above pattern in shown below:
 
   import java.util.ArrayList;
   import java.util.Date;
   import java.util.List;    
   import oracle.bpel.services.workflow.IWorkflowConstants;
   import oracle.bpel.services.workflow.client.IWorkflowServiceClient;
   import oracle.bpel.services.workflow.client.IWorkflowServiceClientConstants;
   import oracle.bpel.services.workflow.client.WorkflowServiceClientFactory;
   import oracle.bpel.services.workflow.query.ITaskQueryService;
   import oracle.bpel.services.workflow.repos.Ordering;
   import oracle.bpel.services.workflow.repos.Predicate;
   import oracle.bpel.services.workflow.repos.TableConstants;
   import oracle.bpel.services.workflow.task.ITaskService;
   import oracle.bpel.services.workflow.task.model.Task;
   import oracle.bpel.services.workflow.verification.IWorkflowContext;      
   
   //User whose task list needs to be queried
   String userid="jstein";
   // Password for the user
   String password = "welcome1";
   
   // You can use keyword to specify sql % around the keyword like: %keyword% on the following
   // attributes: task title, identification key, all textAttributes in task, task number (only
   // if the keyword is a number)
   
   String keyword = null;
   String nullParam = null;
 
   // Get workflow service client
   IWorkflowServiceClient wfSvcClient = WorkflowServiceClientFactory.getWorkflowServiceClient(WorkflowServiceClientFactory.SOAP_CLIENT);
   // Get the workflow context
   IWorkflowContext wfCtx = wfSvcClient.getTaskQueryService().authenticate(userId, password, 
                                 oracle.tip.pc.services.identity.config.ISConfiguration.getDefaultRealmName(),
                                 null);
   // Admin can authenticate on behalf of another user
   //IWorkflowContext adminCtx = wfSvcClient.getTaskQueryService().authenticate(adminUserId, pwd, 
   //                              oracle.tip.pc.services.identity.config.ISConfiguration.getDefaultRealmName(),
   //                              userId);
   
   ITaskQueryService querySvc = wfSvcClient.getTaskQueryService();      
   
   // Only for SOAP clients and it is mandatory for SOAP clients
   Predicate.enableXMLSerialization(true);
   
   // Build the predicate
   Predicate statePredicate = new Predicate(TableConstants.WFTASK_STATE_COLUMN,
                                Predicate.OP_NEQ,
                                IWorkflowConstants.TASK_STATE_ASSIGNED);
        statePredicate.addClause(Predicate.AND,
                         TableConstants.WFTASK_NUMBERATTRIBUTE1_COLUMN,
                         Predicate.OP_IS_NULL,
                         nullParam);
   Predicate datePredicate = new Predicate(TableConstants.WFTASK_ENDDATE_COLUMN,
                                Predicate.OP_ON,
                                new Date());
   Predicate predicate = new Predicate(statePredicate, Predicate.AND, datePredicate);
   
   // Create the ordering
   Ordering ordering = new Ordering(TableConstants.WFTASK_TITLE_COLUMN, true, true);        
     ordering.addClause(TableConstants.WFTASK_PRIORITY_COLUMN, true, true);
     
   // List of display columns
   // For those columns that are not specified here, the queried Task object will not hold any value.
   // For example: If TITLE is not specified, task.getTitle() will return null
   // For the list of most comonly used columns, check the table below
   // Note: TASKID is fetched by default. So there is no need to explicitly specity it.
   List queryColumns = new ArrayList();
     queryColumns.add("TASKNUMBER");     
     queryColumns.add("TITLE");
     queryColumns.add("PRIORITY");
     queryColumns.add("STATE");
     queryColumns.add("ENDDATE");
     queryColumns.add("NUMBERATTRIBUTE1");
     queryColumns.add("TEXTATTRIBUTE1");
     
   // List of optional info
   // Any optionalInfo specified can be fetched from the Task object
   // For example: if you have specified "CustomActions", you can retrieve
   // it using task.getSystemAttributes().getCustomActions();
   // "Actions" (All Actions) - task.getSystemAttributes().getSystemActions()
   // "GroupActions" (Only group Actions: Actions that can be permoded by the user as a member of a group)
   //                - task.getSystemAttributes().getSystemActions()
   // "ShortHistory" - task.getSystemAttributes().getShortHistory()
   List optionalInfo = new ArrayList();
     optionalInfo.add("Actions");
     //optionalInfo.add("GroupActions");
     //optionalInfo.add("CustomActions");
     //optionalInfo.add("ShortHistory");
     // The following is reserved for future use. 
     // If you need them, please use getTaskDetailsById (or) getTaskDetailsByNumber,
     // which will fetch all information related to a task, which includes these
        //optionalInfo.add("Attachments");
        //optionalInfo.add("Comments");
        //optionalInfo.add("Payload");

   List tasksList = querySvc.queryTasks(wfCtx,
                               queryColumns,
                               optionalInfo,
                               ITaskQueryService.ASSIGNMENT_FILTER_MY_AND_GROUP,
                               keyword,
                               predicate, 
                               ordering, 
                               0,0); // No Paging
                               
   // How to use paging:
   // 1. If you need to dynamically calculate paging size (or) to display/find 
   //    out the number of pages, the user has to scroll (Like page X of Y)
   //      Call queryTasks to find out the number of tasks it returns. Using this 
   //      calculate your paging size (The number of taks you want in a page)
   //      Call queryTasks successively varing the startRow and endRow params.  
   //      For example: If the total number of tasks is 30 and your want a paging size
   //      of 10, you can call with (startRow, endRow): (1, 10) (11, 20) (21, 30) 
   // 2. If you have fixed paging size, just keep calling queryTasks successively with 
   //      the paging size (If your paging size is 10, you can call with (startRow, endRow): 
   //      (1, 10) (11, 20) (21, 30) (31, 40).....  until the number of tasks returned is 
   //      less than your paging size (or) there are no more tasks returned     

   if (tasksList != null) { // There are tasks 
     System.out.println("Total number of tasks: " + tasksList.size()); 
     System.out.println("Tasks List: ");
     Task task = null; 
     for (int i = 0; i < tasksList.size(); i++) { 
       task = (Task) tasksList.get(i);          
       System.out.println("Task Number: " + task.getSystemAttributes().getTaskNumber());
       System.out.println("Task Id: " + task.getSystemAttributes().getTaskId());
       System.out.println("Title: " + task.getTitle());
       System.out.println("Priority: " + task.getPriority());
       System.out.println("State: " + task.getSystemAttributes().getState());
       System.out.println();
       // Retrive any Optional Info specified
       // Use task service, to perform operations on the task
     }
   }
   
 Beyond authentication, all methods require the worklist context as the first argument. The worklist context 
 helps the worklist service determine the user requesting the action, whether the user has permission to 
 perform the requested action on the task and so forth. The context also contains information about the 
 user's locale and timezone information.
 

Most commonly used columns
Column objects are defined in oracle.bpel.services.workflow.repos.TableConstants, and they can also be obtained by passing the column name to the static method getColumn() on oracle.bpel.services.workflow.repos.Column.
A list task attributes and column names can be obtained by calling the method ITaskMetadataService.getTaskAttributes(oracle.bpel.services.workflow.verification.IWorkflowContext) or ITaskMetadataService.getTaskAttributesForTaskDefinition(oracle.bpel.services.workflow.verification.IWorkflowContext, java.lang.String).

Column	Description	Column Object	How to retrieve
ACQUIREDBY	Acquired By	WFTASK_ACQUIREDBY_COLUMN	task.getSystemAttributes().getAcquiredBy()
ASSIGNEES	Assignees	WFTASK_ASSIGNEES_COLUMN	task.getSystemAttributes().getAssignees()
REVIEWERS	Reviewers	WFTASK_REVIEWERS_COLUMN	task.getSystemAttributes().getReviewers()
ASSIGNEEGROUPS	Assignee Groups	WFTASK_ASSIGNEEGROUPS_COLUMN	task.getSystemAttributes().getAssigneeGroups()
ASSIGNEEUSERS	Assignee Users	WFTASK_ASSIGNEEUSERS_COLUMN	task.getSystemAttributes().getAssigneeUsers()
CREATOR	Creator	WFTASK_CREATOR_COLUMN	task.getCreator()
DIGITALSIGNATUREREQUIRED	Digital Signature Required	WFTASK_DIGITALSIGNATUREREQUIRED_COLUMN	task.getSystemAttributes().isDigitalSignatureRequired()
EXPIRATIONDATE	Expiration Date	WFTASK_EXPIRATIONDATE_COLUMN	task.getSystemAttributes().getExpirationDate()
IDENTITYCONTEXT	Identity Context	WFTASK_IDENTITYCONTEXT_COLUMN	task.getIdentityContext()
OWNERUSER	Owner User	WFTASK_OWNERUSER_COLUMN	task.getOwnerUser()
OWNERGROUP	Owner Group	WFTASK_OWNERGROUP_COLUMN	task.getOwnerGroup()
PASSWORDREQUIREDONUPDATE	Password Required On Update	WFTASK_PASSWORDREQUIREDONUPDATE_COLUMN	task.getSystemAttributes().isPasswordRequiredOnUpdate()
PRIORITY	Priority	WFTASK_PRIORITY_COLUMN	task.getPriority()
SECURENOTIFICATIONS	Secure Notifications	WFTASK_SECURENOTIFICATIONS_COLUMN	task.getSystemAttributes().isSecureNotifications()
ASSIGNEDDATE	Assigned Date	WFTASK_ASSIGNEDDATE_COLUMN	task.getSystemAttributes().getAssignedDate()
CREATEDDATE	Created Date	WFTASK_CREATEDDATE_COLUMN	task.getSystemAttributes().getCreatedDate()
ENDDATE	End Date	WFTASK_ENDDATE_COLUMN	task.getSystemAttributes().getEndDate()
FROMUSER	From User	WFTASK_FROMUSER_COLUMN	task.getSystemAttributes().getFromUser()
HASSUBTASK	Has Subtask	WFTASK_HASSUBTASK_COLUMN	task.getSystemAttributes().isHasSubTasks()
ISGROUP	Is Group	WFTASK_ISGROUP_COLUMN	task.getSystemAttributes().isIsGroup()
ORIGINALASSIGNEEUSER	Original Assignee User	WFTASK_ORIGINALASSIGNEEUSER_COLUMN	task.getSystemAttributes().()
OUTCOME	Outcome	WFTASK_OUTCOME_COLUMN	task.getSystemAttributes().getOriginalAssigneeUser()
STATE	State	WFTASK_STATE_COLUMN	task.getSystemAttributes().getState()
TASKID	Task Id	WFTASK_TASKID_COLUMN	task.getSystemAttributes().getTaskId()
TASKNUMBER	Task Number	WFTASK_TASKNUMBER_COLUMN	task.getSystemAttributes().getTaskNumber()
UPDATEDBY	Updated By	WFTASK_UPDATEDBY_COLUMN	task.getSystemAttributes().getUpdatedBy()
UPDATEDDATE	Updated Date	WFTASK_UPDATEDDATE_COLUMN	task.getSystemAttributes().getUpdatedDate()
TEXTATTRIBUTE1 to TEXTATTRIBUTE10	Textattribute1 to Textattribute10	WFTASK_TEXTATTRIBUTE1_COLUMN to WFTASK_TEXTATTRIBUTE10_COLUMN	task.getSystemMessageAttributes().getTextAttribute1() to task.getSystemMessageAttributes().getTextAttribute10()
FORMATTRIBUTE1 to FORMATTRIBUTE5	FormAttribute1 to FormAttribute5	WFTASK_FORMATTRIBUTE1_COLUMN to WFTASK_FORMATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getFormAttribute1() to task.getSystemMessageAttributes().getFormAttribute5()
URLATTRIBUTE1 to URLATTRIBUTE5	UrlAttribute1 to UrlAttribute5	WFTASK_URLATTRIBUTE1_COLUMN to WFTASK_URLATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getUrlAttribute1() to task.getSystemMessageAttributes().getUrlAttribute5()
DATEATTRIBUTE1 to DATEATTRIBUTE5	DateAttribute1 to DateAttribute5	WFTASK_DATEATTRIBUTE1_COLUMN to WFTASK_DATEATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getDateAttribute1() to task.getSystemMessageAttributes().getDateAttribute5()
NUMBERATTRIBUTE1 to NUMBERATTRIBUTE5	NumberAttribute1 to NumberAttribute5	WFTASK_NUMBERATTRIBUTE1_COLUMN to WFTASK_NUMBERATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getNumberAttribute1() to task.getSystemMessageAttributes().getNumberAttribute5()
TITLE	Title	WFTASK_TITLE_COLUMN	task.getTitle()
IDENTIFICATIONKEY	Identification key	WFTASK_IDENTIFICATIONKEY_COLUMN	task.getIdentificationKey()
TASKDEFINITIONID	Task Definition Id	WFTASK_TASKDEFINITIONID_COLUMN	task.getTaskDefinitionId()
TASKDEFINITIONNAME	Task Definition Name	WFTASK_TASKDEFINITIONNAME_COLUMN	task.getSystemAttributes().getTaskDefinitionName()
PROTECTEDTEXTATTRIBUTE1 to PROTECTEDTEXTATTRIBUTE10	ProtectedTextAttribute1 to ProtectedTextAttribute10	WFTASK_PROTECTEDTEXTATTRIBUTE1_COLUMN to WFTASK_PROTECTEDTEXTATTRIBUTE10_COLUMN	task.getSystemMessageAttributes().getProtectedTextAttribute1() to task.getSystemMessageAttributes().getProtectedTextAttribute10()
PROTECTEDFORMATTRIBUTE1 to PROTECTEDFORMATTRIBUTE5	ProtectedFormAttribute1 to ProtectedFormAttribute5	WFTASK_PROTECTEDFORMATTRIBUTE1_COLUMN to WFTASK_PROTECTEDFORMATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getFormAttribute1() to task.getSystemMessageAttributes().getFormAttribute5()
PROTECTEDURLATTRIBUTE1 to PROTECTEDURLATTRIBUTE5	ProtectedURLAttribute1 to ProtectedURLAttribute5	WFTASK_PROTECTEDURLATTRIBUTE1_COLUMN to WFTASK_PROTECTEDURLATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getProtectedURLAttribute1() to task.getSystemMessageAttributes().getProtectedURLAttribute5()
PROTECTEDDATEATTRIBUTE1 to PROTECTEDDATEATTRIBUTE5	ProtectedDateAttribute1 to ProtectedDateAttribute5	WFTASK_PROTECTEDDATEATTRIBUTE1_COLUMN to WFTASK_PROTECTEDDATEATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getProtectedDateAttribute1() to task.getSystemMessageAttributes().getProtectedDateAttribute5()
PROTECTEDNUMBERATTRIBUTE1 to PROTECTEDNUMBERATTRIBUTE5	ProtectedNumberAttribute1 to ProtectedNumberAttribute5	WFTASK_PROTECTEDNUMBERATTRIBUTE1_COLUMN to WFTASK_PROTECTEDNUMBERATTRIBUTE5_COLUMN	task.getSystemMessageAttributes().getProtectedNumberAttribute1() to task.getSystemMessageAttributes().getProtectedNumberAttribute5()
APPLICATIONCONTEXT	Application Context	WFTASK_APPLICATIONCONTEXT_COLUMN	task.getApplicationContext()
CATEGORY	Category	WFTASK_CATEGORY_COLUMN	task.getCategory()
DUEDATE	Due Date	WFTASK_DUEDATE_COLUMN	task.getDueDate()
ISPUBLIC	Is Public	WFTASK_ISPUBLIC_COLUMN	task.isIsPublic()
PARTICIPANTNAME	Participant Name	WFTASK_PARTICIPANTNAME_COLUMN	task.getSystemAttributes().getParticipantName()
PERCENTAGECOMPLETE	Percentage Complete	WFTASK_PERCENTAGECOMPLETE_COLUMN	task.getPercentageComplete()
STARTDATE	Start Date	WFTASK_STARTDATE_COLUMN	task.getStartDate()
TASKDISPLAYURL	Task Display Url	WFTASK_TASKDISPLAYURL_COLUMN	task.getTaskDisplayUrl()

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