org.apache.derby.impl.store.access.conglomerate

Class OpenConglomerateScratchSpace

java.lang.Object

org.apache.derby.impl.store.access.conglomerate.OpenConglomerateScratchSpace

All Implemented Interfaces:

DynamicCompiledOpenConglomInfo

public class OpenConglomerateScratchSpace
extends java.lang.Object
implements DynamicCompiledOpenConglomInfo

A utility class to store and use temporary scratch space associated with a conglomerate.

Constructor Summary

Constructors

Constructor and Description
OpenConglomerateScratchSpace(int[] format_ids, int[] collation_ids, boolean hasCollatedTypes) Creates a new scratch space.

Method Summary

Modifier and Type	Method and Description
DataValueDescriptor[]	get_row_for_export(Transaction rawtran) Return an empty template (possibly partial) row to be given back to a client.
RowPosition	get_scratch_row_position() Return a scratch RowPosition.
DataValueDescriptor[]	get_scratch_row(Transaction rawtran) Return an empty template (possibly partial) row to be used and reused internally for processing.
DataValueDescriptor[]	get_template(Transaction rawtran) Return a complete empty row.
boolean	hasCollatedTypes() Tells if there is at least one column with a collation different than UCS BASIC in the conglomerate.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

OpenConglomerateScratchSpace

public OpenConglomerateScratchSpace(int[] format_ids,
                                    int[] collation_ids,
                                    boolean hasCollatedTypes)

Creates a new scratch space.

Parameters:

format_ids - format identifiers for columns in the row

collation_ids - collation identifiers for the columns in the row

hasCollatedTypes - whether there is at least one collated type with a collation other than UCS BASIC in the conglomerate

Method Detail

get_row_for_export

public DataValueDescriptor[] get_row_for_export(Transaction rawtran)
                                         throws StandardException

Return an empty template (possibly partial) row to be given back to a client.

The main use of this is for fetchSet() and fetchNextGroup() which allocate rows and then give them back entirely to the caller.

Returns:

The row to use.

Throws:

StandardException - Standard exception policy.

get_scratch_row

public DataValueDescriptor[] get_scratch_row(Transaction rawtran)
                                      throws StandardException

Return an empty template (possibly partial) row to be used and reused internally for processing.

The main use of this is for qualifying rows where a row has not been provided by the client. This routine cache's a single row for reuse by the caller, if the caller needs 2 concurrent scratch rows, some other mechanism must be used.

Returns:

The row to use.

Throws:

StandardException - Standard exception policy.

get_template

public DataValueDescriptor[] get_template(Transaction rawtran)
                                   throws StandardException

Return a complete empty row.

The main use of this is for searching a tree where a complete copy of the row is needed for searching.

Returns:

The template to use.

Throws:

StandardException - Standard exception policy.

get_scratch_row_position

public RowPosition get_scratch_row_position()

Return a scratch RowPosition.

Used by GenericConglomerateController.delete() and GenericConglomerateController.replace(). It may be reused so callers must insure that object no longer needed before next possible call to get it again.

Returns:

a scratch RowPosition.

hasCollatedTypes

public boolean hasCollatedTypes()

Tells if there is at least one column with a collation different than UCS BASIC in the conglomerate.

Returns:

true if there is at least one column with a collation different than UCS BASIC.