com.goldencode.p2j.persist

Class CacheManager

java.lang.Object

com.goldencode.p2j.persist.CacheManager

public class CacheManager
extends java.lang.Object

Retrieves cache sizes from the directory configuration at initialization. Classes that have their cache size configured can create a LRUCache/HashMap with the configured capacity. If there is no cache size specified for a class, the default value provided is used instead.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CacheManager.ClassKey Represents the key used to differentiate between multiple classes when retrieving their cache sizes.

Field Summary

Fields

Modifier and Type	Field and Description
static java.util.Map<CacheManager.ClassKey,java.lang.Integer>	cacheValues Map that contains cache values for each class (even multiple cache values)
private static CentralLogger	LOG Logger

Constructor Summary

Constructors

Constructor and Description
CacheManager()

Method Summary

Modifier and Type	Method and Description
static <K,V> LRUCache<K,V>	createLRUCache(java.lang.Class<?> clazz, int defaultSize) Creates a LRUCache instance based on the parameters specified.
static <K,V> LRUCache<K,V>	createLRUCache(java.lang.Class<?> clazz, java.lang.String discriminator, int defaultSize) Creates a LRUCache instance based on the parameters specified.
static <K,V> LRUCache<K,V>	createLRUCache(java.lang.Class<?> clazz, java.lang.String discriminator, int defaultSize, java.util.function.Function<V,java.lang.Boolean> expirationTest) Creates a LRUCache instance based on the parameters specified.
static <K,V> LRUCache<K,V>	createLRUCache(java.lang.Class<?> clazz, java.lang.String discriminator, int defaultSize, java.util.function.Function<V,java.lang.Boolean> expirationTest, CapacityPolicy capacityPolicy) Creates a LRUCache instance based on the parameters specified.
static <K,V> java.util.Map<K,V>	createMapCache(java.lang.Class<?> clazz, java.lang.String discriminator, int defaultSize)
private static int	getCacheSize(java.lang.Class<?> clazz, java.lang.String discriminator, int defaultSize) Method that looks for the configured size of a cache and returns it's size.
static void	initialize() Initializes the cacheValues map and if the configuration from the directory file can be accessed, it will populate the map with the configuration values found for each class.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final CentralLogger LOG

Logger

cacheValues

public static java.util.Map<CacheManager.ClassKey,java.lang.Integer> cacheValues

Map that contains cache values for each class (even multiple cache values)

Constructor Detail

CacheManager

public CacheManager()

Method Detail

initialize

public static void initialize()

Initializes the cacheValues map and if the configuration from the directory file can be accessed, it will populate the map with the configuration values found for each class. Note that a class can have multiple caches and can be distinguished by a discriminatory value used to create a ClassKey instance. If only one cache is available for a class, the discriminator can be null.

createLRUCache

public static <K,V> LRUCache<K,V> createLRUCache(java.lang.Class<?> clazz,
                                                 int defaultSize)

Creates a LRUCache instance based on the parameters specified. This method is a wrapper for createLRUCache(Class, String, int), it invokes the method assuming the last parameter is null.

Type Parameters:

K - The key type.

V - The value type.

Parameters:

clazz - The class for which the cache is created.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

Returns:

A LRUCache instance.

createLRUCache

public static <K,V> LRUCache<K,V> createLRUCache(java.lang.Class<?> clazz,
                                                 java.lang.String discriminator,
                                                 int defaultSize)

Creates a LRUCache instance based on the parameters specified. This method is a wrapper for createLRUCache(Class, String, int, Function), it invokes the method assuming the last parameter is null.

Type Parameters:

K - The key type.

V - The value type.

Parameters:

clazz - The class for which the cache is created.

discriminator - The value used to differentiate between caches of the same class.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

Returns:

A LRUCache instance.

createLRUCache

public static <K,V> LRUCache<K,V> createLRUCache(java.lang.Class<?> clazz,
                                                 java.lang.String discriminator,
                                                 int defaultSize,
                                                 java.util.function.Function<V,java.lang.Boolean> expirationTest)

Creates a LRUCache instance based on the parameters specified. This method is a wrapper for createLRUCache(Class, String, int, Function, CapacityPolicy), it invokes the method assuming the last parameter is null.

Type Parameters:

K - The key type.

V - The value type.

Parameters:

clazz - The class for which the cache is created.

discriminator - The value used to differentiate between caches of the same class.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

expirationTest - A function which confirms whether an expiration candidate element may actually be expired.

Returns:

A LRUCache instance.

createLRUCache

public static <K,V> LRUCache<K,V> createLRUCache(java.lang.Class<?> clazz,
                                                 java.lang.String discriminator,
                                                 int defaultSize,
                                                 java.util.function.Function<V,java.lang.Boolean> expirationTest,
                                                 CapacityPolicy capacityPolicy)

Creates a LRUCache instance based on the parameters specified.

Type Parameters:

K - The key type.

V - The value type.

Parameters:

clazz - The class for which the cache is created.

discriminator - The value used to differentiate between caches of the same class.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

expirationTest - A function which confirms whether an expiration candidate element may actually be expired.

capacityPolicy - The policy to follow when capacity cannot be ensured, due to expirationTest vetoing expiration candidates.

Returns:

A LRUCache instance based on the parameters specified that has a default/configured capacity.

createMapCache

public static <K,V> java.util.Map<K,V> createMapCache(java.lang.Class<?> clazz,
                                                      java.lang.String discriminator,
                                                      int defaultSize)

Type Parameters:

K - The key type.

V - The value type.

Parameters:

clazz - The class for which the cache is created.

discriminator - The value used to differentiate between caches of the same class.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

Returns:

A HashMap with a default or a configured capacity.

getCacheSize

private static int getCacheSize(java.lang.Class<?> clazz,
                                java.lang.String discriminator,
                                int defaultSize)

Method that looks for the configured size of a cache and returns it's size. If a discriminator is provided but the ClassKey made of the given clazz and discriminator can't be found, the null will also be used as a discriminator, but only if it was not originally null.

Parameters:

clazz - The class for which the cache is created.

discriminator - The value used to differentiate between caches of the same class.

defaultSize - The default size of the cache if it doesn't exist in the configuration.

Returns:

The size of the cache if it's configured, or the default size.