com.ibm.mm.sdk.common

Class DKProjectionListICM

java.lang.Object

com.ibm.mm.sdk.common.DKProjectionListICM

public class DKProjectionListICM
extends java.lang.Object

Manages attribute projections for optimized data retrieval in CM8.

This class provides a projection list mechanism to filter which attributes are retrieved from the datastore. By specifying only the attributes you need, you can significantly improve performance by reducing network traffic, memory usage, and database query complexity.

Key Features:

• Per-type attribute filtering for optimized retrieval
• Support for special keywords (DK_ICM_SYSTEM_ATTRS, DK_ICM_ALL_ATTRS)
• Reduces network traffic and memory consumption
• Works with DKRetrieveOptionsICM for comprehensive retrieval control

Performance Benefits:

• Filters out large CLOB/BLOB attributes when not needed
• Reduces table joins in database queries
• Minimizes memory allocation for large result sets
• Improves response time for queries returning many objects

Example usage:

 // Create projection list
 DKProjectionListICM projections = DKProjectionListICM.createInstance(datastore);

 // Request only specific attributes for Document type
 projections.addProjection("Document", new String[]{"DocumentTitle", "DateCreated", "Creator"});

 // Request only system attributes for Folder type (for existence checks)
 projections.addProjection("Folder", new String[]{DKConstantICM.DK_ICM_SYSTEM_ATTRS});

 // Use with retrieve options
 DKRetrieveOptionsICM options = DKRetrieveOptionsICM.createInstance(datastore);
 options.baseAttributes(true);
 options.attributeFilters(projections);

 // Retrieve with filtered attributes
 DKDDO doc = datastore.createDDO("Document", DKConstant.DK_CM_DOCUMENT);
 doc.retrieve(options.dkNVPair());
 

See Also:

DKRetrieveOptionsICM, DKConstantICM.DK_ICM_SYSTEM_ATTRS, DKConstantICM.DK_ICM_ALL_ATTRS

Method Summary

Modifier and Type	Method and Description
void	addProjection(java.lang.String itemTypeName, java.lang.String[] attributeNames) Adds a projection for the specified item type.
void	clear() Removes all projections.
static DKProjectionListICM	createInstance(DKDatastoreICM datastore) Factory method to create a new projection list instance.
DKDatastoreICM	getDatastore() Gets the associated datastore.
java.lang.String[]	getItemTypeNames() Gets all item type names that have projections defined.
java.lang.String[]	getProjection(java.lang.String itemTypeName) Gets the projection for the specified item type.
boolean	hasProjection(java.lang.String itemTypeName) Checks if a projection exists for the specified item type.
boolean	isEmpty() Checks if this projection list is empty.
void	removeProjection(java.lang.String itemTypeName) Removes the projection for the specified item type.
int	size() Gets the number of projections defined.
java.lang.String	toString() Returns a string representation of this projection list.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

createInstance

public static DKProjectionListICM createInstance(DKDatastoreICM datastore)

Factory method to create a new projection list instance.

Parameters:

datastore - the datastore to associate with this projection list

Returns:

a new DKProjectionListICM instance

addProjection

public void addProjection(java.lang.String itemTypeName,
                          java.lang.String[] attributeNames)

Adds a projection for the specified item type.

Specifies which attributes should be retrieved for objects of the given type. If a projection already exists for this type, it will be replaced.

Special attribute names:

• DKConstantICM.DK_ICM_SYSTEM_ATTRS - Retrieve only system attributes
• DKConstantICM.DK_ICM_ALL_ATTRS - Retrieve all attributes

Parameters:

itemTypeName - the item type name (e.g., "Document", "Folder")

attributeNames - array of attribute names to retrieve, or null to remove projection

removeProjection

public void removeProjection(java.lang.String itemTypeName)

Removes the projection for the specified item type.

After removal, all attributes will be retrieved for this type (subject to other retrieve options).

Parameters:

itemTypeName - the item type name to remove projection for

getProjection

public java.lang.String[] getProjection(java.lang.String itemTypeName)

Gets the projection for the specified item type.

Parameters:

itemTypeName - the item type name

Returns:

array of attribute names, or null if no projection exists for this type

hasProjection

public boolean hasProjection(java.lang.String itemTypeName)

Checks if a projection exists for the specified item type.

Parameters:

itemTypeName - the item type name

Returns:

true if a projection exists, false otherwise

getItemTypeNames

public java.lang.String[] getItemTypeNames()

Gets all item type names that have projections defined.

Returns:

array of item type names

clear

public void clear()

Removes all projections.

size

public int size()

Gets the number of projections defined.

Returns:

the number of item types with projections

isEmpty

public boolean isEmpty()

Checks if this projection list is empty.

Returns:

true if no projections are defined, false otherwise

getDatastore

public DKDatastoreICM getDatastore()

Gets the associated datastore.

Returns:

the datastore instance

toString

public java.lang.String toString()

Returns a string representation of this projection list.

Overrides:

toString in class java.lang.Object

Returns:

string showing all projections in format "DKProjectionListICM{type1=[attr1,attr2], type2=[attr3,attr4]}"