com.ibm.websphere.wdo
Interface DataListAccessBean

All Superinterfaces:

java.util.Collection, java.util.List, java.io.Serializable

public interface DataListAccessBean

extends java.util.List, java.io.Serializable

Websphere Data Objects - DataListAccessBean Implementation

This interface defines the interface to a DataList. A DataList is an object that represents a view onto a collection of DataObjects. The DataObjects themselves are described by a separate object, an IDataObject.

DataListAccessBean has the following reponsibilities

• Retrieve a page of DataObjects from the underlying collection
• Allow a client to get to the List of DataObjects
• Allow a client to update values in DataObjects. Changes to DataObjects are commited to the back end when commit is called
• Allow clients to request other pages
• Order the results by selected columns

Assumptions:

• DataLists are designed to be kept in HTTP sessions. This means that they must not consume significant memory. In particular:
  • if overqualified updates are being used, DataList will remember all the DataObject data for the current page and all the DataObject data for DataObjects on other pages that have been modified
  • if overqualified updates are not being used, no DataObject data is remembered
  • A small amount of memory is used to remember the values in the sort columns of first/last DataObjects in each page that has been fetched
  • DataList for relational database can be implemented using JDBC drivers that only support resultssets of type TYPE_FORWARD_ONLY

Field Summary

static int	ASCENDING
static int	DESCENDING
static int	UNSORTED

Method Summary

void	addOrderBy(java.lang.String name, int direction) Adds an orderBy to order results by a property in a given direction Orderby is added to the front of the order-by list; If name previously existed in Order By List, it is moved to the front of the order-by list.
void	clearOrderBy() Removes all orderBy clauses set through the addOrderBy API
void	close() Releases any resources, such as database cursors, being held by the DataList for the current page
void	commit() Commits any changes made by calls to put
DataObjectAccessBean	createNewDataObject() Creates a new DataObjectAccessBean of the Type held by this Collection.
void	emptyDataGraph() Creates new empty datagraph
void	execute() executes the query and fills the DataList with the first Page of Data
void	execute(java.util.Map params) Executes the query and fills the DataList with the first Page of Data
void	firstPage() Moves to the first page of DataObjects
java.lang.String	getAction() get the default action upon initialization of this data list (fill/empty/none)
DataObjectAccessBean	getDataObjectAccessBean(int index) Returns the element at the specified position in this list.
java.lang.Long	getNextGeneratedKey() Get the next Key Value from the Auto Key Generator
boolean	getPagination() Returns whether or not this DataList is paginating the results
java.util.Map	getParams() Return the current parameters that are used during execution
int	getTargetPageSize() Return the desired number of DataObjects to return per page.
void	nextPage() resets the position of the DataList so that on the next iteration, the next page of DataObjects will be returned.
void	previousPage() resets the position of the DataList so that on the next iteration, the previous page of DataObjects will be returned.
void	removeOrderBy(java.lang.String name) Removes an Order By added for a given property
void	setAction(java.lang.String action) Set the default action upon initialization of this data list (fill/empty/none)
void	setPagination(boolean pagination) Specify whether or not this DataList shoulds paginate results
void	setParams(java.util.Map map) Set the current parameters that are used during execution
void	setTargetPageSize(int targetPagesize) Specify the desired number of DataObjects per page.

Methods inherited from interface java.util.List

add, add, addAll, addAll, clear, contains, containsAll, equals, get, hashCode, indexOf, isEmpty, iterator, lastIndexOf, listIterator, listIterator, remove, remove, removeAll, retainAll, set, size, subList, toArray, toArray

Field Detail

UNSORTED

public static final int UNSORTED

See Also:

Constant Field Values

ASCENDING

public static final int ASCENDING

See Also:

Constant Field Values

DESCENDING

public static final int DESCENDING

See Also:

Constant Field Values

Method Detail

addOrderBy

public void addOrderBy(java.lang.String name,
                       int direction)
                throws java.lang.UnsupportedOperationException,
                       com.ibm.websphere.wdo.mediator.exception.MediatorException,
                       java.io.IOException

Adds an orderBy to order results by a property in a given direction Orderby is added to the front of the order-by list; If name previously existed in Order By List, it is moved to the front of the order-by list.

Parameters:

name - name of column to order by.

direction - directional order to sort by: DataListAccessBean.UNSORTED, DataListAccessBean.ASCENDING, DataListAccessBean.DESCENDING

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

java.lang.UnsupportedOperationException

java.io.IOException

clearOrderBy

public void clearOrderBy()
                  throws java.lang.UnsupportedOperationException,
                         com.ibm.websphere.wdo.mediator.exception.MediatorException,
                         java.io.IOException

Removes all orderBy clauses set through the addOrderBy API

Throws:

java.lang.UnsupportedOperationException

com.ibm.websphere.wdo.mediator.exception.MediatorException

java.io.IOException

close

public void close()
           throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Releases any resources, such as database cursors, being held by the DataList for the current page

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

commit

public void commit()
            throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Commits any changes made by calls to put

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

createNewDataObject

public DataObjectAccessBean createNewDataObject()
                                         throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Creates a new DataObjectAccessBean of the Type held by this Collection. The created DataObject is added to this DataList by default.

Returns:

the created DataObjectAccessBean

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

execute

public void execute()
             throws com.ibm.websphere.wdo.mediator.exception.MediatorException

executes the query and fills the DataList with the first Page of Data

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

emptyDataGraph

public void emptyDataGraph()
                    throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Creates new empty datagraph

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

execute

public void execute(java.util.Map params)
             throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Executes the query and fills the DataList with the first Page of Data

Parameters:

params - takes a Map of input parameters to pass to the executing query

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

getParams

public java.util.Map getParams()

Return the current parameters that are used during execution

Returns:

map of the current parameters that are used during execution

setParams

public void setParams(java.util.Map map)

Set the current parameters that are used during execution

Parameters:

map - of parameters to be used during execution

firstPage

public void firstPage()
               throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Moves to the first page of DataObjects

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

getDataObjectAccessBean

public DataObjectAccessBean getDataObjectAccessBean(int index)
                                             throws java.lang.IndexOutOfBoundsException,
                                                    com.ibm.websphere.wdo.mediator.exception.MediatorException

Returns the element at the specified position in this list.

Parameters:

index - index of element to return.

Returns:

the element at the specified position in this list.

Throws:

java.lang.IndexOutOfBoundsException - - if the index is out of range (index < 0 || index >= size()).

com.ibm.websphere.wdo.mediator.exception.MediatorException

getPagination

public boolean getPagination()

Returns whether or not this DataList is paginating the results

Returns:

true if this list is paginating results

getTargetPageSize

public int getTargetPageSize()

Return the desired number of DataObjects to return per page.

Returns:

the targeted page size

nextPage

public void nextPage()
              throws com.ibm.websphere.wdo.mediator.exception.MediatorException

resets the position of the DataList so that on the next iteration, the next page of DataObjects will be returned. Pagination is usually implemented by sorting the output, and remembering the values of the sort columns of the first/last DataObject of each page. When fetching the DataObjects for a page, the DataList will append a clause along the lines of " GTR "

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

previousPage

public void previousPage()
                  throws com.ibm.websphere.wdo.mediator.exception.MediatorException

resets the position of the DataList so that on the next iteration, the previous page of DataObjects will be returned.

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

removeOrderBy

public void removeOrderBy(java.lang.String name)
                   throws java.lang.UnsupportedOperationException,
                          com.ibm.websphere.wdo.mediator.exception.MediatorException

Removes an Order By added for a given property

Parameters:

name - name of column to be removed from order-by list.

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException

java.lang.UnsupportedOperationException

setPagination

public void setPagination(boolean pagination)

Specify whether or not this DataList shoulds paginate results

Parameters:

pagination - set whether to paginate results

setTargetPageSize

public void setTargetPageSize(int targetPagesize)

Specify the desired number of DataObjects per page. The resultSet cannot stop between two DataObjects with identical values in the sort columns, so more DataObjects may be returned

Parameters:

targetPagesize - the desired number of DataObjects per page

setAction

public void setAction(java.lang.String action)

Set the default action upon initialization of this data list (fill/empty/none)

Parameters:

action - the default action to perform upon initialization of this data list

getAction

public java.lang.String getAction()

get the default action upon initialization of this data list (fill/empty/none)

Returns:

default action upon initialization of this data list

getNextGeneratedKey

public java.lang.Long getNextGeneratedKey()
                                   throws com.ibm.websphere.wdo.mediator.exception.MediatorException

Get the next Key Value from the Auto Key Generator

Returns:

next Key Value from the Auto Key Generator

Throws:

com.ibm.websphere.wdo.mediator.exception.MediatorException