Package microsim.space

Class SparseObjectSpace

java.lang.Object

microsim.space.AbstractSpace<java.lang.Object>

microsim.space.SparseObjectSpace

All Implemented Interfaces:

ObjectSpace

public class SparseObjectSpace
extends AbstractSpace<java.lang.Object>
implements ObjectSpace

A sparse bidimensional grid containing one object per cell. This object must be used when the ratio between the size of the grid and its average fullness is high. For instance, if you have a grid of 1000 x 1000, with 1000000 of cells and it has to contain 1000 objects, the better solution for memory occupation is to use an ObjVirtualGrid. Obviuosly the ObjVirtualGrid is slower than ObjGrid, but it is much cheaper in memory occupation.

Title: JAS

Description: Java Agent-based Simulation library

Copyright (C) 2002 Michele Sonnessa

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

Author:

Michele Sonnessa

Constructor Summary

Constructors

Constructor	Description
SparseObjectSpace(int xSize, int ySize)	Create a grid with given size.
SparseObjectSpace(AbstractSpace<java.lang.Object> grid)	Create a copy of the given grid.

Method Summary

Modifier and Type	Method	Description
boolean	add(java.lang.Object o)	Add an object implementing IGridPosition interface to the grid.
boolean	addGridPosition(SpacePosition object)	Add an object implementing IGridPosition interface to the grid.
void	clear()	Set all cells to the null value.
boolean	contains(java.lang.Object o)	Test if given object is contained into the grid.
int	countObjectsAt(int x, int y)	Returns the number of objects allocated in cell (x,y).
boolean	equals(java.lang.Object o)	Test if o is the same of this.
java.lang.Object	get(int x, int y)	Return the object stored at the given position.
ObjectSpaceIterator<java.lang.Object>	gridIterator()	Return a GridIterator storing the position of the read value.
java.util.Iterator<java.lang.Object>	iterator()
boolean	moveGridPosition(SpacePosition position, int destinationX, int destinationY)	Move a IGridPosition object from its current position to the specified destination, only if the destination cell is empty.
boolean	remove(java.lang.Object o)	Remove the given object from the grid.
boolean	removeGridPosition(SpacePosition object)	Remove the IGridPosition object from the grid.
void	set(int x, int y, java.lang.Object obj)	Put the given object at the given position.
int	size()	Return the number of objects stored into the grid.
void	swapPositions(int x1, int y1, int x2, int y2)	Swap the content of the (x1, y1) and (x2, y2) cells of the grid.
java.lang.Object[]	toArray()	Return an array of objects stored into the grid.

Methods inherited from class microsim.space.AbstractSpace

boundX, boundY, getMooreNeighborsPositions, getVonNeumannNeighborsPositions, getXSize, getYSize, reflectX, reflectY, torusX, torusY, toString

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface microsim.space.ObjectSpace

boundX, boundY, getXSize, getYSize, reflectX, reflectY, torusX, torusY

Constructor Detail

SparseObjectSpace

public SparseObjectSpace(AbstractSpace<java.lang.Object> grid)

Create a copy of the given grid.

Parameters:

grid - The source grid.

SparseObjectSpace

public SparseObjectSpace(int xSize,
                         int ySize)

Create a grid with given size.

Parameters:

xSize - The width of the grid.

ySize - The height of the grid.

Method Detail

get

public java.lang.Object get(int x,
                            int y)

Return the object stored at the given position.

Specified by:

get in interface ObjectSpace

Specified by:

get in class AbstractSpace<java.lang.Object>

Parameters:

x - The x coordinate.

y - The y coordinate.

Returns:

The requested object.

set

public void set(int x,
                int y,
                java.lang.Object obj)

Put the given object at the given position.

Specified by:

set in interface ObjectSpace

Specified by:

set in class AbstractSpace<java.lang.Object>

Parameters:

x - The x coordinate.

y - The y coordinate.

obj - The object to be stored at the (x, y) cell.

swapPositions

public void swapPositions(int x1,
                          int y1,
                          int x2,
                          int y2)

Swap the content of the (x1, y1) and (x2, y2) cells of the grid.

Specified by:

swapPositions in class AbstractSpace<java.lang.Object>

Parameters:

x1 - The x coordinate for the first cell.

y1 - The y coordinate for the first cell.

x2 - The x coordinate for the second cell.

y2 - The y coordinate for the second cell.

countObjectsAt

public int countObjectsAt(int x,
                          int y)

Description copied from class: AbstractSpace

Returns the number of objects allocated in cell (x,y).

Specified by:

countObjectsAt in interface ObjectSpace

Specified by:

countObjectsAt in class AbstractSpace<java.lang.Object>

Parameters:

x - The x coordinate.

y - The y coordinate.

moveGridPosition

public boolean moveGridPosition(SpacePosition position,
                                int destinationX,
                                int destinationY)

Move a IGridPosition object from its current position to the specified destination, only if the destination cell is empty.

Specified by:

moveGridPosition in interface ObjectSpace

Parameters:

destinationX - The x destination coordinate.

destinationY - The y destination coordinate.

object - An object implementing IGridPosition interface.

Returns:

true if object has been moved, false otherwise.

gridIterator

public ObjectSpaceIterator<java.lang.Object> gridIterator()

Return a GridIterator storing the position of the read value.

Returns:

A GridIterator that scrolls grid from the top-left corner to the bottom-right, reading each line from left to right. It remember the position of the last read value.

size

public int size()

Return the number of objects stored into the grid.

Specified by:

size in class AbstractSpace<java.lang.Object>

Returns:

The sum of cells containing an object.

contains

public boolean contains(java.lang.Object o)

Test if given object is contained into the grid.

Parameters:

o - The object to be tested.

Returns:

True if object is present into the grid.

iterator

public java.util.Iterator<java.lang.Object> iterator()

toArray

public java.lang.Object[] toArray()

Return an array of objects stored into the grid.

Returns:

A vector containing only the objects stored into the grid. The empty cells are ignored.

add

public boolean add(java.lang.Object o)

Add an object implementing IGridPosition interface to the grid. If object implements IGridPosition it stored in the right position of the grid.

Parameters:

o - The IGridPosition object to be added.

Returns:

True if object was added. If o does not implement IGridPosition interface it will not be added and method will return false.

remove

public boolean remove(java.lang.Object o)

Remove the given object from the grid.

Parameters:

o - The object to be removed.

Returns:

True if object was found and removed, false otherwise.

Throws:

java.lang.ClassCastException - If o does not implement IGridPosition interface.

clear

public void clear()

Set all cells to the null value.

Specified by:

clear in class AbstractSpace<java.lang.Object>

equals

public boolean equals(java.lang.Object o)

Test if o is the same of this. There is no content comparing.

Overrides:

equals in class AbstractSpace<java.lang.Object>

Parameters:

o - The object to be compared.

Returns:

True o is this object.

addGridPosition

public boolean addGridPosition(SpacePosition object)

Add an object implementing IGridPosition interface to the grid. If the destination cell is already occupied the method return false and the object is not added.

Specified by:

addGridPosition in interface ObjectSpace

Parameters:

object - The IGridPosition object to be added.

Returns:

True if object has been added. False if destination cell is already occupied or if argument object is null.

removeGridPosition

public boolean removeGridPosition(SpacePosition object)

Remove the IGridPosition object from the grid.

Specified by:

removeGridPosition in interface ObjectSpace

Parameters:

object - The IGridPosition object to be removed.

Returns:

true if object has been removed. False if object is null or is not present on the grid.