org.jaitools.tilecache

Class BasicCacheVisitor

java.lang.Object

org.jaitools.tilecache.BasicCacheVisitor

All Implemented Interfaces:

DiskMemTileCacheVisitor

public class BasicCacheVisitor
extends Object
implements DiskMemTileCacheVisitor

A basic visitor class for DiskMemTileCache that can be used to examine cache contents.

Example of use:

 // Query the cache for tiles that belong to a given image
 // and that are currently resident in memory
 DiskMemTileCache cache = ...
 RenderedImage owner = ...

 Map<BasicCacheVisitor.Key, Object> filters = CollectionFactory.newMap();
 filters.put(BasicCacheVisitor.Key.OWNER, owner);
 filters.put(BasicCachevisitor.Key.RESIDENT, Boolean.TRUE);

 BasicCacheVisitor visitor = new BasicCacheVisitor();
 visitor.setFilters(filters);
 cache.accept(visitor);

 for (DiskCachedTile tile : visitor.getTiles()) {
     System.out.println(String.format("tile %d,%d", tile.getTileX(), tile.getTileY()));
 }
 

Since:

1.0

Version:

$Id$

Author:

Michael Bedward

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BasicCacheVisitor.Key Defines keys to filter the tles visited

Constructor Summary

Constructors

Constructor and Description
BasicCacheVisitor()

Method Summary

Modifier and Type	Method and Description
void	clear() Clear collected tile data.
void	clearFilters() Clear all existing filter conditions
Collection<DiskCachedTile>	getTiles() Returns an unmodifiable collection of tiles retrieved from the cache.
void	setFilter(BasicCacheVisitor.Key key, Object value) Set a single filter condition.
void	setFilters(Map<BasicCacheVisitor.Key,Object> params) Set filter conditions.
void	visit(DiskCachedTile tile, boolean isResident) This method is called by the cache for each tile in turn.

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicCacheVisitor

public BasicCacheVisitor()

Method Detail

setFilters

public void setFilters(Map<BasicCacheVisitor.Key,Object> params)

Set filter conditions. Any existing conditions are cleared.

Parameters:

params - a Map where each key is one of the constants defined by BasicCacheVisitor.Key and each value is the corresponding value to match tiles against

setFilter

public void setFilter(BasicCacheVisitor.Key key,
                      Object value)

Set a single filter condition. Any existing conditions are cleared

Parameters:

key - one of the constants defined by BasicCacheVisitor.Key

value - corresponding value to match tiles against

clearFilters

public void clearFilters()

Clear all existing filter conditions

getTiles

public Collection<DiskCachedTile> getTiles()

Returns an unmodifiable collection of tiles retrieved from the cache.

Returns:

tiles retrieved from the cache

visit

public void visit(DiskCachedTile tile,
                  boolean isResident)

This method is called by the cache for each tile in turn. Tiles that pass this visitor's filter conditions, if any, will be added to the visitor's tile collection.

Specified by:

visit in interface DiskMemTileCacheVisitor

Parameters:

tile - the cached tile being visited

isResident - set by the cache to indicate whether the tile is currently resident in memory

clear

public void clear()

Clear collected tile data. Useful if an instance of this class makes multiple visits to a cache.