edu.stanford.nlp.util
Class CacheMap<K,V>

java.lang.Object
  java.util.AbstractMap<K,V>
      java.util.HashMap<K,V>
          java.util.LinkedHashMap<K,V>
              edu.stanford.nlp.util.CacheMap<K,V>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map<K,V>

public class CacheMap<K,V>
extends java.util.LinkedHashMap<K,V>
implements java.util.Map<K,V>, java.lang.Cloneable, java.io.Serializable

A fixed size hash map with LRU replacement. Can optionally automatically dump itself out to a file as the cache grows.

Author:

Ari Steinberg (ari.steinberg@stanford.edu)

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

java.lang.String

backingFile

Constructor Summary

CacheMap(int numEntries)

CacheMap(int numEntries, float loadFactor)

CacheMap(int numEntries, float loadFactor, boolean accessOrder)

CacheMap(int numEntries, float loadFactor, boolean accessOrder, java.lang.String backingFile)
Constructor.

Method Summary

static <K,V> CacheMap<K,V>	create(int numEntries, float loadFactor, boolean accessOrder, java.lang.String file, boolean useFileParams) Creates a new file-backed CacheMap or loads it in from the specified file if it already exists.
static <K,V> CacheMap<K,V>	create(int numEntries, float loadFactor, java.lang.String file, boolean useFileParams)
static <K,V> CacheMap<K,V>	create(int numEntries, java.lang.String file, boolean useFileParams)
static <K,V> CacheMap<K,V>	create(java.lang.String file, boolean useFileParams)
V	get(java.lang.Object key)
void	printStats(java.io.PrintStream out) Print out cache stats to the specified stream.
V	put(K key, V value) Add the entry to the map, and dump the map to a file if it's been a while since we last did.
protected boolean	removeEldestEntry(java.util.Map.Entry<K,V> eldest)
void	write() Dump out the contents of the cache to the backing file.

Methods inherited from class java.util.LinkedHashMap

clear, containsValue

Methods inherited from class java.util.HashMap

clone, containsKey, entrySet, isEmpty, keySet, putAll, remove, 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

clear, containsKey, containsValue, entrySet, equals, hashCode, isEmpty, keySet, putAll, remove, size, values

Field Detail

backingFile

public java.lang.String backingFile

Constructor Detail

CacheMap

public CacheMap(int numEntries,
                float loadFactor,
                boolean accessOrder,
                java.lang.String backingFile)

Constructor.

Parameters:

numEntries - is the number of entries you want to store in the CacheMap. This is not the same as the number of buckets - that is effected by this and the target loadFactor.

accessOrder - is the same as in LinkedHashMap.

backingFile - is the name of the file to dump this to, if desired.

See Also:

LinkedHashMap

CacheMap

public CacheMap(int numEntries,
                float loadFactor,
                boolean accessOrder)

CacheMap

public CacheMap(int numEntries,
                float loadFactor)

CacheMap

public CacheMap(int numEntries)

Method Detail

create

public static <K,V> CacheMap<K,V> create(int numEntries,
                                         float loadFactor,
                                         boolean accessOrder,
                                         java.lang.String file,
                                         boolean useFileParams)

Creates a new file-backed CacheMap or loads it in from the specified file if it already exists. The parameters passed in are the same as the constructor. If useFileParams is true and the file exists, all of your parameters will be ignored (replaced with those stored in the file itself). If useFileParams is false then we override the settings in the file with the ones you specify (except loadFactor and accessOrder) and reset the stats.

create

public static <K,V> CacheMap<K,V> create(int numEntries,
                                         float loadFactor,
                                         java.lang.String file,
                                         boolean useFileParams)

create

public static <K,V> CacheMap<K,V> create(int numEntries,
                                         java.lang.String file,
                                         boolean useFileParams)

create

public static <K,V> CacheMap<K,V> create(java.lang.String file,
                                         boolean useFileParams)

write

public void write()

Dump out the contents of the cache to the backing file.

removeEldestEntry

protected boolean removeEldestEntry(java.util.Map.Entry<K,V> eldest)

Overrides:

removeEldestEntry in class java.util.LinkedHashMap<K,V>

See Also:

LinkedHashMap.removeEldestEntry(java.util.Map.Entry)

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V>

Overrides:

get in class java.util.LinkedHashMap<K,V>

See Also:

HashMap.get(java.lang.Object)

put

public V put(K key,
             V value)

Add the entry to the map, and dump the map to a file if it's been a while since we last did.

Specified by:

put in interface java.util.Map<K,V>

Overrides:

put in class java.util.HashMap<K,V>

See Also:

HashMap.put(K, V)

printStats

public void printStats(java.io.PrintStream out)

Print out cache stats to the specified stream. Note that in many cases treating puts as misses gives a better version of hit percentage than actually using misses, since it's possible that some of your misses are because you wind up choosing not to cache the particular value (we output both versions). Stats are reset when the cache is loaded in from disk but are otherwise cumulative.