X25519KeyFactory (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- java.lang.Thread
- - net.i2p.util.I2PThread
  - - net.i2p.router.transport.crypto.X25519KeyFactory

All Implemented Interfaces:
Runnable, KeyFactory
```
public class X25519KeyFactory
extends I2PThread
implements KeyFactory
```
Try to keep DH pairs at the ready. It's important to do this in a separate thread, because if we run out, the pairs are generated in the NTCP Pumper thread, and it can fall behind.
Pool sizes scale dynamically based on memory headroom, CPU pressure, and connection demand. The Tuner calls refreshPoolSize() every 30 seconds to adapt to changing conditions.

Nested Class Summary
- Nested classes/interfaces inherited from class net.i2p.util.I2PThread
  I2PThread.OOMEventListener
- Nested classes/interfaces inherited from class java.lang.Thread
  Thread.State, Thread.UncaughtExceptionHandler

Field Summary
- Fields inherited from class java.lang.Thread
  MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary
Constructors
Constructor and Description
X25519KeyFactory(I2PAppContext ctx)
X25519KeyFactory.

Constructors
Constructor and Description
`X25519KeyFactory(I2PAppContext ctx)` X25519KeyFactory.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) void`	`computeTargetSizes()` Dynamically compute target pool sizes based on real-time system signals.
`static X25519KeyFactory`	`getInstance()` Returns the last created instance.
`KeyPair`	`getKeys()` Pulls a prebuilt keypair from the queue, or if not available, construct a new one.
`int`	`getMaxSize()` Returns the current maximum precalc queue size.
`int`	`getMinSize()` Returns the current minimum precalc queue size.
`int`	`getSize()` Returns the current number of precalc keys queued.
`void`	`recordEmpty()` Record an empty-queue event for demand tracking.
`void`	`refreshPoolSize()` Called by the Tuner every 30 seconds.
`void`	`returnUnused(KeyPair kp)` Return an unused DH key builder to be put back onto the queue for reuse.
`void`	`run()` run.
`void`	`setMaxSize(int max)` Sets the maximum precalc queue size.
`void`	`setMinSize(int min)` Sets the minimum precalc queue size.
`void`	`shutdown()` Note that this stops the singleton precalc thread.

Methods inherited from class net.i2p.util.I2PThread
addOOMEventListener, fireOOM, removeOOMEventListener, start

Methods inherited from class java.lang.Thread
activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - X25519KeyFactory
```
public X25519KeyFactory(I2PAppContext ctx)
```
    X25519KeyFactory.
- Method Detail
  - computeTargetSizes
```
void computeTargetSizes()
```
    Dynamically compute target pool sizes based on real-time system signals.
    Signals used:
    - Free memory headroom — more free memory = larger pool budget
    - Memory pressure — high usage = shrink aggressively
    - CPU load (job lag) — busy CPU = limit generation rate
    - Empty queue events — zero empties = low demand shrinks pool
    - Active peers — more connections = more key demand
    Memory budget: up to 2% of free heap when active, 0.5% when idle.
  - getInstance
```
public static X25519KeyFactory getInstance()
```
    Returns the last created instance.
    Returns:
    the instance
  - getKeys
```
public KeyPair getKeys()
```
    Pulls a prebuilt keypair from the queue, or if not available, construct a new one.
    Specified by:
    getKeys in interface KeyFactory
    Returns:
    the keys
  - getMaxSize
```
public int getMaxSize()
```
    Returns the current maximum precalc queue size.
    Returns:
    the max size
  - getMinSize
```
public int getMinSize()
```
    Returns the current minimum precalc queue size.
    Returns:
    the min size
  - getSize
```
public int getSize()
```
    Returns the current number of precalc keys queued.
    Returns:
    the size
  - recordEmpty
```
public void recordEmpty()
```
    Record an empty-queue event for demand tracking. Called by getKeys() when the pool is depleted.
  - refreshPoolSize
```
public void refreshPoolSize()
```
    Called by the Tuner every 30 seconds. Manages fill ceiling (_maxSize) based on demand and memory pressure. Does NOT override the Tuner-set _minSize — the Tuner owns that value via setMinSize().
  - returnUnused
```
public void returnUnused(KeyPair kp)
```
    Return an unused DH key builder to be put back onto the queue for reuse.
  - run
```
public void run()
```
    run.
    Specified by:
    run in interface Runnable
    Overrides:
    run in class I2PThread
  - setMaxSize
```
public void setMaxSize(int max)
```
    Sets the maximum precalc queue size.
  - setMinSize
```
public void setMinSize(int min)
```
    Sets the minimum precalc queue size.
  - shutdown
```
public void shutdown()
```
    Note that this stops the singleton precalc thread. You don't want to do this if there are multiple routers in the JVM. Fix this if you care. See Router.shutdown().

Class X25519KeyFactory

Nested Class Summary

Nested classes/interfaces inherited from class net.i2p.util.I2PThread

Nested classes/interfaces inherited from class java.lang.Thread

Field Summary

Fields inherited from class java.lang.Thread

Constructor Summary

Method Summary

Methods inherited from class net.i2p.util.I2PThread

Methods inherited from class java.lang.Thread

Methods inherited from class java.lang.Object

Constructor Detail

X25519KeyFactory

Method Detail

computeTargetSizes

getInstance

getKeys

getMaxSize

getMinSize

getSize

recordEmpty

refreshPoolSize

returnUnused

run

setMaxSize

setMinSize

shutdown