com.yahoo.bard.webservice.data.cache

Class HashDataCache<T extends Serializable>

java.lang.Object

com.yahoo.bard.webservice.data.cache.HashDataCache<T>

Type Parameters:

T - the type of values maintained by this map

All Implemented Interfaces:

DataCache<T>

public class HashDataCache<T extends Serializable>
extends Object
implements DataCache<T>

DataCache using hashed keys to reduce the key length for the provided underlying cache.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	HashDataCache.Pair<K,V> Key/Value pair.

Constructor Summary

Constructors

Constructor and Description
HashDataCache(DataCache<HashDataCache.Pair<String,T>> cache) Creates cache hashing with default SHA-512 algorithm.
HashDataCache(DataCache<HashDataCache.Pair<String,T>> cache, MessageDigest md) Creates cache hashing with given algorithm.

Method Summary

Modifier and Type	Method and Description
void	clear() Removes all of the mappings from this cache.
T	get(String key) Lookup pair key/value by hashkey but verify found key matches original key.
String	hash(String key) Get the hash encoding of a key string.
boolean	set(String key, T value) Put a value on a key in a data cache.

Methods inherited from class java.lang.Object

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

Constructor Detail

HashDataCache

public HashDataCache(DataCache<HashDataCache.Pair<String,T>> cache,
                     MessageDigest md)

Creates cache hashing with given algorithm.

Parameters:

cache - provided underlying cache

md - the MessageDigest to extract hash algorithm

See Also:

MessageDigest.getInstance(String)

HashDataCache

public HashDataCache(DataCache<HashDataCache.Pair<String,T>> cache)

Creates cache hashing with default SHA-512 algorithm.

Parameters:

cache - provided underlying cache

Method Detail

hash

public String hash(String key)

Get the hash encoding of a key string.

Parameters:

key - The input string to encode.

Returns:

The hash encoding of the key as string. Returns null if the method fails to produce a hash.

get

public final T get(String key)

Lookup pair key/value by hashkey but verify found key matches original key.

Specified by:

get in interface DataCache<T extends Serializable>

Parameters:

key - The key whose associated value is to be returned

Returns:

the value to which the specified key is mapped, or null if this map contains no mapping for the key or there is a collision

set

public final boolean set(String key,
                         T value)

Description copied from interface: DataCache

Put a value on a key in a data cache.

Specified by:

set in interface DataCache<T extends Serializable>

Parameters:

key - the key under which this object should be added.

value - the object to store

Returns:

a boolean representing success of this operation

clear

public void clear()

Description copied from interface: DataCache

Removes all of the mappings from this cache.

Specified by:

clear in interface DataCache<T extends Serializable>