SimpleLRUCache (jTDS API)

java.lang.Object
- java.util.AbstractMap<K,V>
- - java.util.HashMap
  - - net.sourceforge.jtds.jdbc.cache.SimpleLRUCache

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map
```
public class SimpleLRUCache
extends java.util.HashMap
```
Simple LRU cache for any type of object. Implemented as an extended HashMap with a maximum size and an aggregated List as LRU queue.

Version:

$Id: SimpleLRUCache.java,v 1.1 2005/04/25 11:46:56 alin_sinpalean Exp $

Author:

Brett Wooldridge

See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class java.util.AbstractMap
  java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>
- Nested classes/interfaces inherited from interface java.util.Map
  java.util.Map.Entry<K,V>

Field Summary

Fields
Modifier and Type Field and Description

private java.util.LinkedList list
LRU list.

private int maxCacheSize
Maximum cache size.

Fields
Modifier and Type	Field and Description
`private java.util.LinkedList`	`list` LRU list.
`private int`	`maxCacheSize` Maximum cache size.

Constructor Summary

Constructors
Constructor and Description

SimpleLRUCache(int maxCacheSize)
Constructs a new LRU cache instance.

Constructors
Constructor and Description
`SimpleLRUCache(int maxCacheSize)` Constructs a new LRU cache instance.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Overrides clear() to also clear the LRU list.
`private void`	`freshenKey(java.lang.Object key)` Moves the specified value to the top of the LRU list (the bottom of the list is where least recently used items live).
`java.lang.Object`	`get(java.lang.Object key)` Overrides `get()` so that it also updates the LRU list.
`java.lang.Object`	`put(java.lang.Object key, java.lang.Object value)` Overrides `put()` so that it also updates the LRU list.
`java.lang.Object`	`remove(java.lang.Object key)`

Methods inherited from class java.util.HashMap
clone, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, forEach, getOrDefault, isEmpty, keySet, merge, putAll, putIfAbsent, remove, replace, replace, replaceAll, size, values

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

- Field Detail
  - maxCacheSize
```
private final int maxCacheSize
```
    Maximum cache size.
  - list
```
private final java.util.LinkedList list
```
    LRU list.
- Constructor Detail
  - SimpleLRUCache
```
public SimpleLRUCache(int maxCacheSize)
```
    Constructs a new LRU cache instance.
    
    Parameters:
    
    maxCacheSize - the maximum number of entries in this cache before entries are aged off
- Method Detail
  - clear
```
public void clear()
```
    Overrides clear() to also clear the LRU list.
    
    Specified by:
    
    clear in interface java.util.Map
    
    Overrides:
    
    clear in class java.util.HashMap
  - put
```
public java.lang.Object put(java.lang.Object key,
                            java.lang.Object value)
```
    Overrides put() so that it also updates the LRU list.
    
    Specified by:
    
    put in interface java.util.Map
    
    Overrides:
    
    put in class java.util.HashMap
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the key
    
    Returns:
    
    previous value associated with key or null if there was no mapping for key; a null return can also indicate that the cache previously associated null with the specified key
    
    See Also:
    
    Map.put(Object, Object)
  - get
```
public java.lang.Object get(java.lang.Object key)
```
    Overrides get() so that it also updates the LRU list.
    
    Specified by:
    
    get in interface java.util.Map
    
    Overrides:
    
    get in class java.util.HashMap
    
    Parameters:
    
    key - key with which the expected value is associated
    
    Returns:
    
    the value to which the cache maps the specified key, or null if the map contains no mapping for this key
  - remove
```
public java.lang.Object remove(java.lang.Object key)
```
    Specified by:
    
    remove in interface java.util.Map
    
    Overrides:
    
    remove in class java.util.HashMap
    
    See Also:
    
    Map.remove(Object)
  - freshenKey
```
private void freshenKey(java.lang.Object key)
```
    Moves the specified value to the top of the LRU list (the bottom of the list is where least recently used items live).
    
    Parameters:
    
    key - key of the value to move to the top of the list

Class SimpleLRUCache

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

Nested classes/interfaces inherited from interface java.util.Map

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.util.HashMap

Methods inherited from class java.util.AbstractMap

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Map

Field Detail

maxCacheSize

list

Constructor Detail

SimpleLRUCache

Method Detail

clear

put

get

remove

freshenKey