wyvern.kernel.maps
Class GameHashMap

java.lang.Object
  java.util.AbstractMap
      java.util.HashMap
          wyvern.kernel.maps.GameHashMap

All Implemented Interfaces:

java.lang.Cloneable, java.util.Map, java.io.Serializable

public class GameHashMap

extends java.util.HashMap

A version of MultiHashMap that uses MapCells as its buckets, so it can group similar GameObjects. This implementation is not synchronized. If multiple threads are going to access it concurrently, and at least one of the threads modifies the map structurally (adds or removes keys), you must synchronize access to all its read/write methods.

Version:

1.0, Jan 15, 1998

Author:

Steve Yegge

See Also:

Serialized Form

Constructor Summary

GameHashMap()

Method Summary

void	add(int x, int y, java.lang.Object value) Adds an object to the map.
void	add(java.lang.Object key, java.lang.Object value) Adds an object reference to the map.
java.lang.Object	get(java.lang.Object key) This operation is a bit ambiguous; it's not clear whether it should return the bucket or the first item in the bucket, so I'm just getting rid of it completely.
protected Cell	getBucket(int x, int y) Returns the bucket at the specified location.
protected Cell	getBucket(java.lang.Object key) Returns the bucket at the specified location.
java.lang.Object	getFirst(int x, int y) Returns the first object at the specified location.
java.lang.Object	getFirst(Point p) Returns the first object at the specified location.
java.util.Iterator	iterator(int x, int y) Returns an iterator over the objects at (x, y).
protected Cell	makeBucket(java.lang.Object key) Creates and returns a new bucket at the specified location.
java.util.List	objectsAt(int x, int y) Returns a list of the objects at location (x, y);
java.util.List	objectsAt(Point p) Returns a list of the objects at location p.
java.util.Iterator	objectsInRect(int x, int y, int w, int h) Returns an Iterator over the objects in the specified rectangle.
void	printTree() Prints out the contents of the map, for debugging.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Don't let them try the put() operation directly, since we use buckets as our values.
void	remove(int x, int y, java.lang.Object obj) Removes the specified object at the specified location.
void	remove(Point p, java.lang.Object obj) Removes the specified object from the specified location.
java.util.Collection	values() Returns a Collection view of the buckets (Cells) at the nonempty locations in this map.
java.util.Collection	values(java.lang.Object key) Returns a Collection view of the values under the given key.

Methods inherited from class java.util.HashMap

clear, clone, containsKey, containsValue, entrySet, isEmpty, keySet, putAll, remove, size

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

GameHashMap

public GameHashMap()

Method Detail

get

public java.lang.Object get(java.lang.Object key)

This operation is a bit ambiguous; it's not clear whether it should return the bucket or the first item in the bucket, so I'm just getting rid of it completely.

Parameters:

key - a 2D map location to check for objects

Throws:

java.lang.UnsupportedOperationException - (always).

add

public void add(int x,
                int y,
                java.lang.Object value)

Adds an object to the map.

Parameters:

x - the x coordinate to add at

y - the y coordinate to add at

value - the object to add (must be of class GameObject)

add

public void add(java.lang.Object key,
                java.lang.Object value)

Adds an object reference to the map.

Parameters:

key - the 2D map coordinate at which to put the object

value - the GameObject to place at that coordinate

Throws:

java.lang.ClassCastException - if value isn't a GameObject

remove

public void remove(Point p,
                   java.lang.Object obj)

Removes the specified object from the specified location.

Parameters:

p - the location to remove it from

obj - the object to remove. Does nothing if not found.

remove

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

Removes the specified object at the specified location.

Parameters:

x - map x location

y - map y location

obj - object to remove. Does nothing if not found.

values

public java.util.Collection values()

Returns a Collection view of the buckets (Cells) at the nonempty locations in this map. An iterator over this Collection will return the buckets in the same order as their keys (top to bottom, left to right).

Returns:

a Collection view of the buckets in the map.

getFirst

public java.lang.Object getFirst(Point p)

Returns the first object at the specified location.

Parameters:

p - the map location to examine

Returns:

the first object found at the location, or null if none.

getFirst

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

Returns the first object at the specified location.

Parameters:

x - map x location

y - map y location

Returns:

the first object found at the location, or null if none.

values

public java.util.Collection values(java.lang.Object key)

Returns a Collection view of the values under the given key. The Collection supports the same semantics as that returned by MapCell.values().

Parameters:

key - the key to search for

Returns:

a Collection view of the bucket under that key (the bucket is a MapCell).

objectsAt

public java.util.List objectsAt(int x,
                                int y)

Returns a list of the objects at location (x, y);

Parameters:

x - map x location

y - map y location

Returns:

a List of objects at (x, y). Can return null if no objects are there, or an empty list.

iterator

public java.util.Iterator iterator(int x,
                                   int y)

Returns an iterator over the objects at (x, y).

Parameters:

x - map x location

y - map y location

Returns:

an Iterator over the objects at (x, y). Returns null if there are no objects at (x, y).

objectsAt

public java.util.List objectsAt(Point p)

Returns a list of the objects at location p.

Parameters:

p - the location to examine

Returns:

a List of objects at p (can be null or empty list)

objectsInRect

public java.util.Iterator objectsInRect(int x,
                                        int y,
                                        int w,
                                        int h)

Returns an Iterator over the objects in the specified rectangle.

Parameters:

x - map x location

y - map y location

w - rectangle width

h - rectangle height

Returns:

an Iterator that traverses the objects in the passed rectangle. The Iterator skips quickly over empty locations, so this is no more expensive than (and in fact often faster than) iterating over a rectangle in a dense array.

put

public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)

Don't let them try the put() operation directly, since we use buckets as our values.

Parameters:

key - the key

value - the value

Throws:

java.lang.UnsupportedOperationException - (always)

getBucket

protected Cell getBucket(java.lang.Object key)

Returns the bucket at the specified location.

Parameters:

key - the Point at which to look for a bucket

Returns:

the bucket, or null if none found

getBucket

protected Cell getBucket(int x,
                         int y)

Returns the bucket at the specified location.

Parameters:

x - map x location

y - map y location

makeBucket

protected Cell makeBucket(java.lang.Object key)

Creates and returns a new bucket at the specified location.

Parameters:

key - the Point at which to place the bucket

Returns:

the created bucket

printTree

public void printTree()

Prints out the contents of the map, for debugging.