mondrian.rolap

Interface CellKey

All Superinterfaces:

Serializable

All Known Implementing Classes:

CellKey.Four, CellKey.Many, CellKey.One, CellKey.Three, CellKey.Two, CellKey.Zero

public interface CellKey
extends Serializable

A CellKey is used as a key in maps which access cells by their position.

CellKey is also used within SparseSegmentDataset to store values within aggregations.

It is important that CellKey is memory-efficient, and that the Object.hashCode() and Object.equals(java.lang.Object) methods are extremely efficient. There are particular implementations for the most likely cases where the number of axes is 1, 2, 3 and 4 as well as a general implementation.

To create a key, call the CellKey.Generator.newCellKey(int[]) method.

Since:

10 August, 2001

Author:

jhyde

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	CellKey.Four
static class	CellKey.Generator
static class	CellKey.Many
static class	CellKey.One
static class	CellKey.Three
static class	CellKey.Two
static class	CellKey.Zero

Method Summary

Methods

Modifier and Type	Method and Description
CellKey	copy() Returns a mutable copy of this CellKey.
int	getAxis(int axis) Returns the axisth axis value.
int	getOffset(int[] axisMultipliers) Returns the offset of the cell in a raster-scan order.
int[]	getOrdinals() Returns the axis keys as an array.
void	setAxis(int axis, int value) Sets a given axis.
void	setOrdinals(int[] pos) This method make a copy of the int array parameter.
int	size() Returns the number of axes.

Method Detail

size

int size()

Returns the number of axes.

Returns:

number of axes

getOrdinals

int[] getOrdinals()

Returns the axis keys as an array.

Note: caller should treat the array as immutable. If the contents of the array are modified, behavior is unspecified.

Returns:

Array of axis keys

setOrdinals

void setOrdinals(int[] pos)

This method make a copy of the int array parameter. Throws a RuntimeException if the int array size is not the size of the CellKey.

Parameters:

pos - Array of axis keys

getAxis

int getAxis(int axis)

Returns the axisth axis value.

Parameters:

axis - Axis ordinal

Returns:

Value of the axisth axis

Throws:

ArrayIndexOutOfBoundsException - if axis is out of range

setAxis

void setAxis(int axis,
           int value)

Sets a given axis.

Parameters:

axis - Axis ordinal

value - Value

Throws:

RuntimeException - if axis parameter is larger than size()

copy

CellKey copy()

Returns a mutable copy of this CellKey.

Returns:

Mutable copy

getOffset

int getOffset(int[] axisMultipliers)

Returns the offset of the cell in a raster-scan order.

For example, if the axes have lengths {2, 5, 10} then cell (2, 3, 4) has offset

(2 * mulitiplers[0]) + (3 * multipliers[1]) + (4 * multipliers[2])
= (2 * 50) + (3 * 10) + (4 * 1)
= 134

The multipliers are the product of the lengths of all later axes, in this case (50, 10, 1).

Parameters:

axisMultipliers - For each axis, the product of the lengths of later axes

Returns:

The raster-scan ordinal of this cell