gov.nasa.worldwind.cache

Interface SessionCache

All Known Implementing Classes:

BasicSessionCache

public interface SessionCache

SessionCache is a general receiving area for data represented as key-value pairs. Entries in a SessionCache may persist for the length of a Virtual Machine's run time, but may be evicted at any time.

Eviction of SessionCache entries is accomplished by controlling the maximum number of entries in the cache. This maximum value is set by calling setCapacity(int). A SessionCache may be implemented with any eviction policy (including a policy of no eviction). Most implementations evict the eldest entry added to the cache.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all entries from the cache.
boolean	contains(java.lang.Object key) Returns true if the cache contains a specified key, and false if it does not.
java.lang.Object	get(java.lang.Object key) Returns a reference to an entry's value in the cache corresponding to a specified key, or null if no entry with that key exists.
int	getCapacity() Returns the maximum number of entries in the cache.
int	getEntryCount() Returns the number of entries currently in the cache.
java.util.Set<java.lang.Object>	getKeySet() Returns a Set view of the keys contained in the cache.
void	put(java.lang.Object key, java.lang.Object value) Adds an entry in the cache with a specified key and value.
java.lang.Object	remove(java.lang.Object key) Removes the entry with the specified key from the cache, and returns that entry's value.
void	setCapacity(int capacity) Sets the maximum number of entries in the cache.

Method Detail

clear

void clear()

Removes all entries from the cache.

contains

boolean contains(java.lang.Object key)

Returns true if the cache contains a specified key, and false if it does not.

Parameters:

key - the entry key in question.

Returns:

true if the cache contains the key; false otherwise.

get

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

Returns a reference to an entry's value in the cache corresponding to a specified key, or null if no entry with that key exists.

Parameters:

key - the entry key to look for.

Returns:

a reference to the found entry's value.

getCapacity

int getCapacity()

Returns the maximum number of entries in the cache.

Returns:

maximum number of entries in the cache.

getEntryCount

int getEntryCount()

Returns the number of entries currently in the cache.

Returns:

number of cached entries.

getKeySet

java.util.Set<java.lang.Object> getKeySet()

Returns a Set view of the keys contained in the cache.

Returns:

a Set view of the keys contained in the cache.

put

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

Adds an entry in the cache with a specified key and value.

Parameters:

key - the entry's key.

value - the entry's value.

remove

java.lang.Object remove(java.lang.Object key)

Removes the entry with the specified key from the cache, and returns that entry's value. If no entry exists for the specified key, this does nothing and returns null.

Parameters:

key - the entry key to look for.

Returns:

a reference to the removed entry's value, or null of no entry matches the specified key.

setCapacity

void setCapacity(int capacity)

Sets the maximum number of entries in the cache.

Parameters:

capacity - maximum number of enties in the cache.