Process Class Relationships

filenet.vw.api
Class VWQueueQuery

java.lang.Object
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  +--filenet.vw.api.VWQuery
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        +--filenet.vw.api.VWQueueQuery

public final class VWQueueQuery
extends filenet.vw.api.VWQuery

Use this class to query for queue elements, work objects, or Instruction elements. A given instance of this class returns a series of single type of item. A query completes when the next() method returns null a null value.

VWQueueQuery contains methods next() and hasNext() which function similarly to the next() and hasNext() methods in the Iterator interface in Java 2.

See Also:
VWQueue.startQuery(String, Object[], Object[], int, String, Object[]), VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int), VWQueue, VWQueueElement, VWWorkObject, VWStepElement

Field Summary
static int QUERY_GET_TRANSLATED_SYSTEM_FIELDS
          Deprecated. Not replaced. This is the default.
static int QUERY_LOCK_OBJECTS
          Value of 16. Flag used to specify that items returned from a query should become locked.
static int QUERY_MAX_VALUES_INCLUSIVE
          Value of 64. Flag used to specify that maximum values passed in a query are inclusive, i.e.
static int QUERY_MIN_VALUES_INCLUSIVE
          Value of 32. Flag used to specify that minimum values passed in a query are inclusive, i.e.
static int QUERY_READ_BOUND
          Value of 2. Flag used to specify that items returned from a query should include those that are already bound to a user or machine.
static int QUERY_READ_LOCKED
          Value of 1. Flag used to specify that items returned from a query should include those that are already locked.
static int QUERY_READ_UNWRITABLE
          Value of 4. Flag used to specify that items returned from a query should include those that are Read-only.
 
Method Summary
 int fetchCount()
          Gets the integer value indicating the number of records that can be retrieved, using this queueQuery object.
 VWInstructionElement[] fetchInstructionElements(int bufferSize)
          Deprecated. Replaced by next()
 VWQueueElement[] fetchQueueElements(int bufferSize)
          Deprecated. Replaced by next()
 VWWorkObject[] fetchWorkObjects(int bufferSize)
          Deprecated. Replaced by next()
 int getElementType()
          Gets the fetch type of this VWQueueQuery object.
 VWQueue getQueue()
          Gets the queue retrieved by the VWQueue.createQuery() method or the deprecated VWQueue.startQuery() method.
 boolean hasNext()
          Indicates whether another element can be fetched from this VWQueueQuery instance.
 boolean isDone()
          Deprecated. Replaced by next()
 java.lang.Object next()
          Retrieves the subsequent element for this VWQueueQuery instance. Invoke this method repeatedly to retrieve a series of objects that can be cast to the fetch type of this VWQueueQuery object, as specified by the VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call that created this VWQueueQuery instance.
 void resetFetch()
          Resets the last element fetched for this queue query object.
 java.lang.String toString()
          Retrieves a string version of the current query's queue name.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

QUERY_READ_LOCKED

public static final int QUERY_READ_LOCKED
Value of 1. Flag used to specify that items returned from a query should include those that are already locked.
See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_READ_BOUND

public static final int QUERY_READ_BOUND
Value of 2. Flag used to specify that items returned from a query should include those that are already bound to a user or machine.
See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_READ_UNWRITABLE

public static final int QUERY_READ_UNWRITABLE
Value of 4. Flag used to specify that items returned from a query should include those that are Read-only.
See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_LOCK_OBJECTS

public static final int QUERY_LOCK_OBJECTS
Value of 16. Flag used to specify that items returned from a query should become locked. See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_MIN_VALUES_INCLUSIVE

public static final int QUERY_MIN_VALUES_INCLUSIVE
Value of 32. Flag used to specify that minimum values passed in a query are inclusive, i.e. the comparison should be "greater than or equal to" rather than "greater than" (which is the default).
See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_MAX_VALUES_INCLUSIVE

public static final int QUERY_MAX_VALUES_INCLUSIVE
Value of 64. Flag used to specify that maximum values passed in a query are inclusive, i.e. the comparison should be "less than or equal to" rather than "less than" (which is the default).
See the queryFlags parameter of VWRoster.startQuery(..), VWQueue.createQuery(..), and VWQueue.startQuery(..)(deprecated)

QUERY_GET_TRANSLATED_SYSTEM_FIELDS

public static final int QUERY_GET_TRANSLATED_SYSTEM_FIELDS
Deprecated. Not replaced. This is the default.

Value of 512. Flag to specify that the query items returned from the query should include translated system field values.
Method Detail

fetchWorkObjects

public VWWorkObject[] fetchWorkObjects(int bufferSize)
                                throws VWException
Deprecated. Replaced by next()

Fetches a specific number of work objects. Call the method once for each work object the query being fetched. If the number of requested elements (specified in the bufferSize parameter) is greater than the number of elements returned in the query, all remaining elements return in a single fetch. An instance of this class returns only one type of item. Therefore, an error occurs if this call follows a call to the deprecated fetchInstructionElements or the fetchQueueElements methods.
Parameters:
bufferSize - An integer value specifying the maximum number of Work Objects to return for each fetch operation. The value must be greater than zero (0). The server imposes a maximum; therefore, the number of returned work objects might be smaller than the number specified here.
Returns:
An array of VWWorkObjects that represents the fetched items. If no more objects are available to fetch, the method returns a null value.
Throws:
VWException - Thrown if it cannot fetch a specific number of work objects.

fetchQueueElements

public VWQueueElement[] fetchQueueElements(int bufferSize)
                                    throws VWException
Deprecated. Replaced by next()

Fetches a specific number of queue elements. Call the method once for each queue element being fetched. If the number of requested elements (specified in the bufferSize parameter) is greater than the number of elements returned in the query, all remaining elements return in a single fetch. An instance of this class returns only one type of item. Therefore, an error occurs if this call follows a call to the deprecated fetchInstructionElements or the fetchWorkObjects methods.
Parameters:
bufferSize - An integer value specifying the maximum number of elements to return for each fetch operation. The value must be greater than zero (0). The server imposes a maximum; therefore, the number of returned elements might be smaller than the number specified in the parameter.
Returns:
An array of VWQueueElement objects that represent the fetched items. If no more objects are available to fetch, the method returns a null value.
Throws:
VWException - Thrown if it cannot fetch a specific number of queue elements.

fetchInstructionElements

public VWInstructionElement[] fetchInstructionElements(int bufferSize)
                                                throws VWException
Deprecated. Replaced by next()

Fetches a specific number of Instruction elements. Call the method once for each Instruction element being fetched. If the number of requested elements (specified in the bufferSize parameter) is greater than the number of elements returned in the query, all remaining elements return in a single fetch. An instance of this class returns only one type of item. Therefore, an error occurs if this call follows a call to the deprecated fetchQueueElements or the fetchWorkObjects methods.
Parameters:
bufferSize - An integer value specifying the maximum number of elements to return for each fetch operation. The value must be greater than zero (0). The server imposes a maximum; therefore, the number of returned elements might be smaller than the number specified in the parameter.
Returns:
An array of VWInstructionElement objects that represent the fetched items. If no more objects are available to fetch, the method returns a null value.
Throws:
VWException - Thrown if it cannot fetch a specific number of Instruction elements.

getQueue

public VWQueue getQueue()
Gets the queue retrieved by the VWQueue.createQuery() method or the deprecated VWQueue.startQuery() method.
Returns:
A Queue object retrieved by the VWQueue.startQuery() method.
See Also:
VWQueue

isDone

public boolean isDone()
Deprecated. Replaced by next()

Indicates whether the query completed.
Returns:
A Boolean value. The method returns true if no elements to fetch; otherwise, the method returns false, which indicates there are more elements to fetch.

toString

public java.lang.String toString()
Retrieves a string version of the current query's queue name.
Overrides:
toString in class java.lang.Object
Returns:
A string that contains the name of the queue.

resetFetch

public void resetFetch()
Resets the last element fetched for this queue query object. New fetch results include previously fetched elements.
Returns:
Nothing
Since:
VWWS3.10

getElementType

public int getElementType()
Gets the fetch type of this VWQueueQuery object.
Returns:
An integer value indicating the type of the elements.

Fetch types are:

  • -1: VWFetchType.FETCH_TYPE_NONE
  • 1: VWFetchType.FETCH_TYPE_WORKOBJECT
  • 2: VWFetchType.FETCH_TYPE_INSTRUCTION_ELEMENT
  • 3: VWFetchType.FETCH_TYPE_QUEUE_ELEMENT
  • 5: VWFetchType.FETCH_TYPE_STEP_ELEMENT

If VWFetchType.FETCH_TYPE_NONE (-1) returns, the application used the deprecated VWQueue.startQuery() method to create this object.

Since:
VWWS3.10

next

public java.lang.Object next()
                      throws VWException
Retrieves the subsequent element for this VWQueueQuery instance. Invoke this method repeatedly to retrieve a series of objects that can be cast to the fetch type of this VWQueueQuery object, as specified by the VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call that created this VWQueueQuery instance. Returns null when no more objects can be returned.

To use this method, create a VWQueueQuery object with a VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call, which specifies a range of objects to be fetched, a SQL filter expression, and the type of object to be fetched. The resulting query object will use a default buffer size of 50 retrieved items.

After a set of items in the current retrieval buffer is exhausted, additional items will be retrieved from the Process server and buffered. The effective buffer block size is the lesser of the number specified with a preceding VWQueue.setBufferSize(int) call and the number imposed by the Process server limit.

You can modify retrieval performance by changing the retrieval buffer size. To change the current retrieval buffer size, set it with a VWQueue.setBufferSize(int) call from the same instance of the VWQueue class that created the current VWQueueQuery object. In other words, after you reset the buffer size, you must create a new VWQueueQuery object (which will contain this next() method) with VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int). In the new instance of VWQueueQuery, the next() method will use the new buffer size.
Note
This method requires a buffer size greater than 1 to operate properly.

Returns:
An object that represents an item of the fetch type specified in the VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) method that created the current VWQueueQuery object, or null (indicating there are no more objects in the series).
Note
The returned object should be cast to the fetch type specified by the creating VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call.
Throws:
VWException - Various causes. A possible cause may be using the deprecated VWQueue.startQuery(String, Object[], Object[], int, String, Object[]) method to create the current VWQueueQuery instance, instead of a VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call.
Since:
VWWS3.10
See Also:
hasNext()

hasNext

public boolean hasNext()
                throws VWException
Indicates whether another element can be fetched from this VWQueueQuery instance.
Returns:
true if there are more elements that can be fetched.
Note
This method requires a buffer size greater than 1 to operate properly. The default buffersize is 50.
Throws:
VWException - Various causes. A possible cause may be using the deprecated VWQueue.startQuery(String, Object[], Object[], int, String, Object[]) method to create the current VWQueueQuery instance, instead of a VWQueue.createQuery(String, Object[], Object[], int, String, Object[], int) call.
See Also:
next()

fetchCount

public int fetchCount()
               throws VWException
Gets the integer value indicating the number of records that can be retrieved, using this queueQuery object. Results are approximate because the record set may change before the query returns.
Returns:
An integer value indicating the number of records that could be retrieved in the queue, using this VWQueueQuery object queue.
Throws:
VWException - Thrown if it cannot get the integer value indicating the number of records that can be retrieved, using this VWQueueQuery object queue. One cause of this is an incorrect query parameter.
Since:
VWWS3.10


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