Package io.deephaven.base.string.cache

Class ConcurrentUnboundedStringCache<STRING_LIKE_TYPE extends CharSequence>

java.lang.Object

io.deephaven.base.string.cache.ConcurrentUnboundedStringCache<STRING_LIKE_TYPE>

All Implemented Interfaces:

StringCache<STRING_LIKE_TYPE>

public class ConcurrentUnboundedStringCache<STRING_LIKE_TYPE extends CharSequence>
extends Object
implements StringCache<STRING_LIKE_TYPE>

A very limited interface is specified, in order to decouple typeAdapter pooling and related concerns from the cache itself. StringCompatibles or Strings used as keys (or values) when probing/populating the cache are allowed to use their own hashCode() implementation. This is dangerous, because we rely on our key implementation to hash CharSequences identically to a String of the same characters. An assertion in the value factory should catch any cases where the built-in assumption breaks down, but we've deemed that unnecessary at this time. Specify "debug" in the constructor if you need this check. String.hashCode()'s implementation has been stable since JDK 1.2, and is specified in the JavaDocs. This implementation is thread-safe, and lock-free except for the insertion of new cached Strings on a cache miss. StringCompatible implementation thread-safety is a separate concern.

Field Summary

Fields inherited from interface io.deephaven.base.string.cache.StringCache

CAPACITY_UNBOUNDED

Constructor Summary

Constructors

Constructor	Description
ConcurrentUnboundedStringCache(@NotNull StringCacheTypeAdapter<STRING_LIKE_TYPE> typeAdapter, int initialCapacity, boolean debug)

Method Summary

Modifier and Type	Method	Description
final int	capacity()	Get a hint about this cache's capacity and behavior.
final STRING_LIKE_TYPE	getCachedString(@NotNull StringCompatible protoString)
final STRING_LIKE_TYPE	getCachedString(@NotNull String string)
final STRING_LIKE_TYPE	getEmptyString()
final @NotNull Class<STRING_LIKE_TYPE>	getType()

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.deephaven.base.string.cache.StringCache

getCachedString

Constructor Details

ConcurrentUnboundedStringCache

public ConcurrentUnboundedStringCache(@NotNull
 @NotNull StringCacheTypeAdapter<STRING_LIKE_TYPE> typeAdapter,
 int initialCapacity,
 boolean debug)

Parameters:

typeAdapter - The type adapter for this cache

initialCapacity - Initial capacity of the map backing this cache

debug - Whether constructed Strings should be checked for consistency against the StringCompatible used

Method Details

capacity

public final int capacity()

Description copied from interface: StringCache

Get a hint about this cache's capacity and behavior.

Specified by:

capacity in interface StringCache<STRING_LIKE_TYPE extends CharSequence>

Returns:

-1 : This is an unbounded cache. 0 : This "cache" doesn't actually perform any caching. >0 : Actual capacity bound.

getType

@NotNull
public final @NotNull Class<STRING_LIKE_TYPE> getType()

Specified by:

getType in interface StringCache<STRING_LIKE_TYPE extends CharSequence>

Returns:

The type of the elements in this cache.

getEmptyString

@NotNull
public final STRING_LIKE_TYPE getEmptyString()

Specified by:

getEmptyString in interface StringCache<STRING_LIKE_TYPE extends CharSequence>

Returns:

A cached STRING_LIKE_TYPE that represents the empty string.

getCachedString

@NotNull
public final STRING_LIKE_TYPE getCachedString(@NotNull
 @NotNull StringCompatible protoString)

Specified by:

getCachedString in interface StringCache<STRING_LIKE_TYPE extends CharSequence>

Parameters:

protoString - The string-like CharSequence to look up

Returns:

A cached STRING_LIKE_TYPE that corresponds to the current value of the CharSequence expressed by protoString

getCachedString

@NotNull
public final STRING_LIKE_TYPE getCachedString(@NotNull
 @NotNull String string)

Specified by:

getCachedString in interface StringCache<STRING_LIKE_TYPE extends CharSequence>

Parameters:

string - The String to look up

Returns:

A cached STRING_LIKE_TYPE that corresponds to the CharSequence expressed by string