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

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

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