ByteCache | Javadocs [I2P+]

java.lang.Object

net.i2p.util.TryCache<ByteArray>

net.i2p.util.ByteCache

public final class ByteCacheextends TryCache<ByteArray>

Cache the objects frequently used to reduce memory churn. The ByteArray should be held onto as long as the data referenced in it is needed.

For small arrays where the management of valid bytes in ByteArray and prezeroing isn't required, use SimpleByteArray instead.

Heap size control - survey of usage:

+---------------------------------------------------------------------+
|   Size    |   Max   |  MaxMem  | From                               |
+---------------------------------------------------------------------+
|     1K    |    32   |    32K   | tunnel TrivialPreprocessor         |
|     1K    |   512   |   512K   | tunnel FragmentHandler             |
|     1K    |   512   |   512K   | tunnel I2NP TunnelDataMessage      |
|     1K    |   512   |   512K   | tunnel FragmentedMessage           |
|   1572    |    64   |   100K   | UDP InboundMessageState            |
|   1730    |   128   |   216K   | streaming MessageOutputStream      |
|     4K    |    32   |    28K   | I2PTunnelRunner                    |
|     8K    |     8   |    64K   | I2PTunnel HTTPResponseOutputStream |
|    16K    |    16   |   256K   | I2PSnark                           |
|    32K    |     4   |   128K   | SAM StreamSession                  |
|    32K    |    10   |   320K   | SAM v2StreamSession                |
|    32K    |    64   |     2M   | UDP OMS                            |
|    32K    |   128   |     4M   | streaming MessageInputStream       |
|    36K    |    64   |  2.25M   | streaming PacketQueue              |
|    40K    |     8   |   320K   | DataHelper decompress              |
|    64K    |    64   |     4M   | UDP MessageReceiver                |
+---------------------------------------------------------------------+

Nested Class Summary
Nested classes/interfaces inherited from class TryCache
TryCache.ObjectFactory<T>
Modifier and Type
Class
Description
static interface
TryCache.ObjectFactory<T>
Factory interface for creating new objects in TryCache.
Method Summary
Modifier and Type
Method
Description
static void
clearAll()
Clear everything (memory pressure).
static ByteCache
getInstance(int cacheSize, int size)
Shared cache for the given entry size and capacity.
final void
release(ByteArray entry)
Put this structure back onto the available cache for reuse.
final void
release(ByteArray entry, boolean shouldZero)
Release the entry back to the cache, optionally zeroing its contents first.
void
resize(int maxCachedEntries)
Resize the cache to a new capacity.
Methods inherited from class TryCache
acquire, clear, getAcquireCount, getCapacity, getDiscardCount, getLastUnderflowTime, getMissCount, getReleaseCount, shrink, size, wasUnderfilled
Modifier and Type
Method
Description
ByteArray
acquire()
Acquire an object from the cache or create a new one.
void
clear()
Clear all cached items.
long
getAcquireCount()
Return total acquire() count (hits + misses).
int
getCapacity()
Return the current cache capacity.
long
getDiscardCount()
Return the number of release() calls that were discarded because the cache was full.
long
getLastUnderflowTime()
Timestamp of the last underflow.
long
getMissCount()
Return the number of acquire() calls that found an empty cache (misses required allocating a new object).
long
getReleaseCount()
Return total release() count (returned to cache).
void
shrink(int targetSize)
Shrink the cache to the target size, evicting excess items.
int
size()
Current number of cached items.
boolean
wasUnderfilled(long thresholdMillis)
Check if the cache has been underfilled longer than the threshold.
Methods inherited from class Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details
- getInstance
  public static ByteCache getInstance(int cacheSize, int size)
  Shared cache for the given entry size and capacity.
  Parameters:
  cacheSize - the number of entries to hold, trimmed as needed to stay under MAX_CACHE
  size - the byte length of every cached entry, raised to at least 1 and used as the cache key
  Returns:
  the shared cache for that entry size, creating it if needed
- clearAll
  public static void clearAll()
  Clear everything (memory pressure).
- resize
  public void resize(int maxCachedEntries)
  Resize the cache to a new capacity.
  Overrides:
  resize in class TryCache<ByteArray>
  Parameters:
  maxCachedEntries - the new maximum number of entries to cache
- release
  public final void release(ByteArray entry)
  Put this structure back onto the available cache for reuse.
  Overrides:
  release in class TryCache<ByteArray>
  Parameters:
  entry - the value to hand back to the cache for reuse
- release
  public final void release(ByteArray entry, boolean shouldZero)
  Release the entry back to the cache, optionally zeroing its contents first.
  Parameters:
  entry - the structure being handed back, ignored if null or the wrong size
  shouldZero - true to overwrite the entry's bytes with zeroes before pooling it

Nested Class Summary

Nested classes/interfaces inherited from class TryCache

Method Summary

Methods inherited from class TryCache

Methods inherited from class Object

Method Details

getInstance

clearAll

resize

release

release