net.sf.farrago.fem.fennel
Interface FemWindowDefClass

All Superinterfaces:

RefBaseObject, RefClass, RefFeatured

All Known Implementing Classes:

FemWindowDefClass$Hib

public interface FemWindowDefClass
extends RefClass

WindowDef class proxy interface.

The definition of a window inside a FemWindowStreamDef.

A window has either a logical or physical range, and contains a number of partitions:

• A logical window is defined by a range of values, and may have several partitions.
• A physical window is defined by a range of rows, and may have several partitions.

Note: This type should not be subclassed, implemented or directly instantiated by clients. It is generated from a MOF metamodel and implemented by Enki or MDR.

Method Summary

FemWindowDef	createFemWindowDef() The default factory operation used to create an instance object.
FemWindowDef	createFemWindowDef(FemTupleProjection orderKeyList, boolean physical, String range, int offset) Creates an instance object having attributes initialized by the passed values.

Methods inherited from interface javax.jmi.reflect.RefClass

refAllOfClass, refAllOfType, refCreateInstance, refCreateStruct, refCreateStruct, refGetEnum, refGetEnum

Methods inherited from interface javax.jmi.reflect.RefFeatured

refGetValue, refGetValue, refInvokeOperation, refInvokeOperation, refSetValue, refSetValue

Methods inherited from interface javax.jmi.reflect.RefBaseObject

equals, hashCode, refImmediatePackage, refMetaObject, refMofId, refOutermostPackage, refVerifyConstraints

Method Detail

createFemWindowDef

FemWindowDef createFemWindowDef()

The default factory operation used to create an instance object.

Returns:

The created instance object.

createFemWindowDef

FemWindowDef createFemWindowDef(FemTupleProjection orderKeyList,
                                boolean physical,
                                String range,
                                int offset)

Creates an instance object having attributes initialized by the passed values.

Parameters:

orderKeyList -

List of columns to sort the window on. For example, in WINDOW w AS (ORDER BY hiredate PARTITION BY gender ROWS 5 PRECEDING), the order list is "hiredate".

Often the optimizer will have ensured that the input stream is already sorted on the sort key, or at least a subset of it; for infinite relations, this is required in order to perform aggregation. See FemWindowStreamDef.getInputOrderKeyList().

physical -

True if the window is physical (defined by a number of rows); false if the window is logical (defined by a range of values).

range -

If physical, the number of rows; if logical, the value range (for example, 3,600,000 milliseconds).

offset -

This is the offset of the window. Positive value refers to a leading window and negative value refers to a trailing window.

Returns:

The created instance object.