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//
// ========================================================================
// Copyright (c) 1995-2022 Mort Bay Consulting Pty Ltd and others.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package com.signalfx.shaded.jetty.util;
import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Function;
import java.util.stream.Collectors;
import com.signalfx.shaded.jetty.util.annotation.ManagedAttribute;
import com.signalfx.shaded.jetty.util.annotation.ManagedObject;
import com.signalfx.shaded.jetty.util.component.Dumpable;
import com.signalfx.shaded.jetty.util.component.DumpableCollection;
import com.signalfx.shaded.jetty.util.log.Log;
import com.signalfx.shaded.jetty.util.log.Logger;
import com.signalfx.shaded.jetty.util.thread.Locker;
/**
* A pool of objects, with optional support for multiplexing,
* max usage count and several optimized strategies plus
* an optional {@link ThreadLocal} cache of the last release entry.
* When the method {@link #close()} is called, all {@link Closeable}s
* object pooled by the pool are also closed.
*
* @param the type of the pooled objects
*/
@ManagedObject
public class Pool implements AutoCloseable, Dumpable
{
private static final Logger LOGGER = Log.getLogger(Pool.class);
private final List entries = new CopyOnWriteArrayList<>();
private final int maxEntries;
private final StrategyType strategyType;
/*
* The cache is used to avoid hammering on the first index of the entry list.
* Caches can become poisoned (i.e.: containing entries that are in use) when
* the release isn't done by the acquiring thread or when the entry pool is
* undersized compared to the load applied on it.
* When an entry can't be found in the cache, the global list is iterated
* with the configured strategy so the cache has no visible effect besides performance.
*/
private final Locker locker = new Locker();
private final ThreadLocal cache;
private final AtomicInteger nextIndex;
private volatile boolean closed;
@Deprecated
private volatile int maxUsage = -1;
@Deprecated
private volatile int maxMultiplex = -1;
/**
* The type of the strategy to use for the pool.
* The strategy primarily determines where iteration over the pool entries begins.
*/
public enum StrategyType
{
/**
* A strategy that looks for an entry always starting from the first entry.
* It will favour the early entries in the pool, but may contend on them more.
*/
FIRST,
/**
* A strategy that looks for an entry by iterating from a random starting
* index. No entries are favoured and contention is reduced.
*/
RANDOM,
/**
* A strategy that uses the {@link Thread#getId()} of the current thread
* to select a starting point for an entry search. Whilst not as performant as
* using the {@link ThreadLocal} cache, it may be suitable when the pool is substantially smaller
* than the number of available threads.
* No entries are favoured and contention is reduced.
*/
THREAD_ID,
/**
* A strategy that looks for an entry by iterating from a starting point
* that is incremented on every search. This gives similar results to the
* random strategy but with more predictable behaviour.
* No entries are favoured and contention is reduced.
*/
ROUND_ROBIN
}
/**
* Construct a Pool with a specified lookup strategy and no
* {@link ThreadLocal} cache.
*
* @param strategyType The strategy to used for looking up entries.
* @param maxEntries the maximum amount of entries that the pool will accept.
*/
public Pool(StrategyType strategyType, int maxEntries)
{
this(strategyType, maxEntries, false);
}
/**
* Construct a Pool with the specified thread-local cache size and
* an optional {@link ThreadLocal} cache.
*
* @param strategyType The strategy to used for looking up entries.
* @param maxEntries the maximum amount of entries that the pool will accept.
* @param cache True if a {@link ThreadLocal} cache should be used to try the most recently released entry.
*/
public Pool(StrategyType strategyType, int maxEntries, boolean cache)
{
this.maxEntries = maxEntries;
this.strategyType = Objects.requireNonNull(strategyType);
this.cache = cache ? new ThreadLocal<>() : null;
this.nextIndex = strategyType == StrategyType.ROUND_ROBIN ? new AtomicInteger() : null;
}
/**
* @return the number of reserved entries
*/
@ManagedAttribute("The number of reserved entries")
public int getReservedCount()
{
return (int)entries.stream().filter(Entry::isReserved).count();
}
/**
* @return the number of idle entries
*/
@ManagedAttribute("The number of idle entries")
public int getIdleCount()
{
return (int)entries.stream().filter(Entry::isIdle).count();
}
/**
* @return the number of in-use entries
*/
@ManagedAttribute("The number of in-use entries")
public int getInUseCount()
{
return (int)entries.stream().filter(Entry::isInUse).count();
}
/**
* @return the number of closed entries
*/
@ManagedAttribute("The number of closed entries")
public int getClosedCount()
{
return (int)entries.stream().filter(Entry::isClosed).count();
}
/**
* @return the maximum number of entries
*/
@ManagedAttribute("The maximum number of entries")
public int getMaxEntries()
{
return maxEntries;
}
/**
* @return the default maximum multiplex count of entries
* @deprecated Multiplex functionalities will be removed
*/
@ManagedAttribute("The default maximum multiplex count of entries")
@Deprecated
public int getMaxMultiplex()
{
return maxMultiplex == -1 ? 1 : maxMultiplex;
}
/**
* Retrieves the max multiplex count for the given pooled object.
*
* @param pooled the pooled object
* @return the max multiplex count for the given pooled object
* @deprecated Multiplex functionalities will be removed
*/
@Deprecated
protected int getMaxMultiplex(T pooled)
{
return getMaxMultiplex();
}
/**
* Sets the default maximum multiplex count for the Pool's entries.
*
* @param maxMultiplex the default maximum multiplex count of entries
* @deprecated Multiplex functionalities will be removed
*/
@Deprecated
public final void setMaxMultiplex(int maxMultiplex)
{
if (maxMultiplex < 1)
throw new IllegalArgumentException("Max multiplex must be >= 1");
try (Locker.Lock l = locker.lock())
{
if (closed)
return;
if (entries.stream().anyMatch(MonoEntry.class::isInstance))
throw new IllegalStateException("Pool entries do not support multiplexing");
this.maxMultiplex = maxMultiplex;
}
}
/**
* Returns the maximum number of times the entries of the pool
* can be acquired.
*
* @return the default maximum usage count of entries
* @deprecated MaxUsage functionalities will be removed
*/
@ManagedAttribute("The default maximum usage count of entries")
@Deprecated
public int getMaxUsageCount()
{
return maxUsage;
}
/**
* Retrieves the max usage count for the given pooled object.
*
* @param pooled the pooled object
* @return the max usage count for the given pooled object
* @deprecated MaxUsage functionalities will be removed
*/
@Deprecated
protected int getMaxUsageCount(T pooled)
{
return getMaxUsageCount();
}
/**
* Sets the maximum usage count for the Pool's entries.
* All existing idle entries that have a usage count larger
* than this new value are removed from the Pool and closed.
*
* @param maxUsageCount the default maximum usage count of entries
* @deprecated MaxUsage functionalities will be removed
*/
@Deprecated
public final void setMaxUsageCount(int maxUsageCount)
{
if (maxUsageCount == 0)
throw new IllegalArgumentException("Max usage count must be != 0");
// Iterate the entries, remove overused ones and collect a list of the closeable removed ones.
List copy;
try (Locker.Lock l = locker.lock())
{
if (closed)
return;
if (entries.stream().anyMatch(MonoEntry.class::isInstance))
throw new IllegalStateException("Pool entries do not support max usage");
this.maxUsage = maxUsageCount;
copy = entries.stream()
.filter(entry -> entry.isIdleAndOverUsed() && remove(entry) && entry.pooled instanceof Closeable)
.map(entry -> (Closeable)entry.pooled)
.collect(Collectors.toList());
}
// Iterate the copy and close the collected entries.
copy.forEach(IO::close);
}
/**
* Creates a new disabled slot into the pool.
* The returned entry must ultimately have the {@link Entry#enable(Object, boolean)}
* method called or be removed via {@link Pool.Entry#remove()} or
* {@link Pool#remove(Pool.Entry)}.
*
* @param allotment the desired allotment, where each entry handles an allotment of maxMultiplex,
* or a negative number to always trigger the reservation of a new entry.
* @return a disabled entry that is contained in the pool,
* or null if the pool is closed or if the pool already contains
* {@link #getMaxEntries()} entries, or the allotment has already been reserved
* @deprecated Use {@link #reserve()} instead
*/
@Deprecated
public Entry reserve(int allotment)
{
try (Locker.Lock l = locker.lock())
{
if (closed)
return null;
int space = maxEntries - entries.size();
if (space <= 0)
return null;
if (allotment >= 0 && (getReservedCount() * getMaxMultiplex()) >= allotment)
return null;
Entry entry = newEntry();
entries.add(entry);
return entry;
}
}
/**
* Creates a new disabled slot into the pool.
* The returned entry must ultimately have the {@link Entry#enable(Object, boolean)}
* method called or be removed via {@link Pool.Entry#remove()} or
* {@link Pool#remove(Pool.Entry)}.
*
* @return a disabled entry that is contained in the pool,
* or null if the pool is closed or if the pool already contains
* {@link #getMaxEntries()} entries
*/
public Entry reserve()
{
try (Locker.Lock l = locker.lock())
{
if (closed)
{
if (LOGGER.isDebugEnabled())
LOGGER.debug("{} is closed, returning null reserved entry", this);
return null;
}
// If we have no space
int entriesSize = entries.size();
if (entriesSize >= maxEntries)
{
if (LOGGER.isDebugEnabled())
LOGGER.debug("{} has no space: {} >= {}, returning null reserved entry", this, entriesSize, maxEntries);
return null;
}
Entry entry = newEntry();
entries.add(entry);
if (LOGGER.isDebugEnabled())
LOGGER.debug("{} returning new reserved entry {}", this, entry);
return entry;
}
}
private Entry newEntry()
{
// Do not allow more than 2 implementations of Entry, otherwise call sites in Pool
// referencing Entry methods will become mega-morphic and kill the performance.
if (maxMultiplex >= 0 || maxUsage >= 0)
return new MultiEntry();
return new MonoEntry();
}
/**
* Acquires the entry from the pool at the specified index.
* This method bypasses the thread-local cache mechanism.
*
* @param idx the index of the entry to acquire.
* @return the specified entry or null if there is none at the specified index or if it is not available.
* @deprecated No longer supported. Instead use a {@link StrategyType} to configure the pool.
*/
@Deprecated
public Entry acquireAt(int idx)
{
if (closed)
return null;
try
{
Entry entry = entries.get(idx);
if (entry.tryAcquire())
return entry;
}
catch (IndexOutOfBoundsException e)
{
// no entry at that index
}
return null;
}
/**
* Acquires an entry from the pool.
* Only enabled entries will be returned from this method
* and their {@link Entry#enable(Object, boolean)}
* method must not be called.
*
* @return an entry from the pool or null if none is available.
*/
public Entry acquire()
{
if (closed)
return null;
int size = entries.size();
if (size == 0)
return null;
if (cache != null)
{
Pool.Entry entry = cache.get();
if (entry != null && entry.tryAcquire())
return entry;
}
int index = startIndex(size);
for (int tries = size; tries-- > 0;)
{
try
{
Pool.Entry entry = entries.get(index);
if (entry != null && entry.tryAcquire())
return entry;
}
catch (IndexOutOfBoundsException e)
{
LOGGER.ignore(e);
size = entries.size();
// Size can be 0 when the pool is in the middle of
// acquiring a connection while another thread
// removes the last one from the pool.
if (size == 0)
break;
}
index = (index + 1) % size;
}
return null;
}
private int startIndex(int size)
{
switch (strategyType)
{
case FIRST:
return 0;
case RANDOM:
return ThreadLocalRandom.current().nextInt(size);
case ROUND_ROBIN:
return nextIndex.getAndUpdate(c -> Math.max(0, c + 1)) % size;
case THREAD_ID:
return (int)(Thread.currentThread().getId() % size);
default:
throw new IllegalArgumentException("Unknown strategy type: " + strategyType);
}
}
/**
* Acquires an entry from the pool,
* reserving and creating a new entry if necessary.
*
* @param creator a function to create the pooled value for a reserved entry.
* @return an entry from the pool or null if none is available.
*/
public Entry acquire(Function.Entry, T> creator)
{
Entry entry = acquire();
if (entry != null)
return entry;
entry = reserve();
if (entry == null)
return null;
T value;
try
{
value = creator.apply(entry);
}
catch (Throwable th)
{
remove(entry);
throw th;
}
if (value == null)
{
remove(entry);
return null;
}
return entry.enable(value, true) ? entry : null;
}
/**
* Releases an {@link #acquire() acquired} entry to the pool.
* Entries that are acquired from the pool but never released
* will result in a memory leak.
*
* @param entry the value to return to the pool
* @return true if the entry was released and could be acquired again,
* false if the entry should be removed by calling {@link #remove(Pool.Entry)}
* and the object contained by the entry should be disposed.
*/
public boolean release(Entry entry)
{
if (closed)
return false;
boolean released = entry.tryRelease();
if (released && cache != null)
cache.set(entry);
return released;
}
/**
* Removes an entry from the pool.
*
* @param entry the value to remove
* @return true if the entry was removed, false otherwise
*/
public boolean remove(Entry entry)
{
if (closed)
return false;
if (!entry.tryRemove())
{
if (LOGGER.isDebugEnabled())
LOGGER.debug("Attempt to remove an object from the pool that is still in use: {}", entry);
return false;
}
boolean removed = entries.remove(entry);
if (!removed && LOGGER.isDebugEnabled())
LOGGER.debug("Attempt to remove an object from the pool that does not exist: {}", entry);
return removed;
}
public boolean isClosed()
{
return closed;
}
@Override
public void close()
{
if (LOGGER.isDebugEnabled())
LOGGER.debug("Closing {}", this);
List copy;
try (Locker.Lock l = locker.lock())
{
closed = true;
copy = new ArrayList<>(entries);
entries.clear();
}
// iterate the copy and close its entries
for (Entry entry : copy)
{
boolean removed = entry.tryRemove();
if (removed)
{
if (entry.pooled instanceof Closeable)
IO.close((Closeable)entry.pooled);
}
else
{
if (LOGGER.isDebugEnabled())
LOGGER.debug("Pooled object still in use: {}", entry);
}
}
}
public int size()
{
return entries.size();
}
public Collection values()
{
return Collections.unmodifiableCollection(entries);
}
@Override
public void dump(Appendable out, String indent) throws IOException
{
Dumpable.dumpObjects(out, indent, this,
new DumpableCollection("entries", entries));
}
@Override
public String toString()
{
return String.format("%s@%x[inUse=%d,size=%d,capacity=%d,closed=%b]",
getClass().getSimpleName(),
hashCode(),
getInUseCount(),
size(),
getMaxEntries(),
isClosed());
}
/**
* A Pool entry that holds metadata and a pooled object.
*/
public abstract class Entry
{
// The pooled object. This is not volatile as it is set once and then never changed.
// Other threads accessing must check the state field above first, so a good before/after
// relationship exists to make a memory barrier.
private T pooled;
/**
* Enables this, previously {@link #reserve() reserved}, Entry.
* An entry returned from the {@link #reserve()} method must be enabled with this method,
* once and only once, before it is usable by the pool.
* The entry may be enabled and not acquired, in which case it is immediately available to be
* acquired, potentially by another thread; or it can be enabled and acquired atomically so that
* no other thread can acquire it, although the acquire may still fail if the pool has been closed.
*
* @param pooled the pooled object for this Entry
* @param acquire whether this Entry should be atomically enabled and acquired
* @return whether this Entry was enabled
* @throws IllegalStateException if this Entry was already enabled
*/
public boolean enable(T pooled, boolean acquire)
{
Objects.requireNonNull(pooled);
if (!isReserved())
{
if (isClosed())
return false; // Pool has been closed
throw new IllegalStateException("Entry already enabled: " + this);
}
this.pooled = pooled;
if (tryEnable(acquire))
return true;
this.pooled = null;
if (isClosed())
return false; // Pool has been closed
throw new IllegalStateException("Entry already enabled: " + this);
}
/**
* @return the pooled object
*/
public T getPooled()
{
return pooled;
}
/**
* Releases this Entry.
* This is equivalent to calling {@link Pool#release(Pool.Entry)} passing this entry.
*
* @return whether this Entry was released
*/
public boolean release()
{
return Pool.this.release(this);
}
/**
* Removes this Entry from the Pool.
* This is equivalent to calling {@link Pool#remove(Pool.Entry)} passing this entry.
*
* @return whether this Entry was removed
*/
public boolean remove()
{
return Pool.this.remove(this);
}
/**
* Tries to enable, and possible also acquire, this Entry.
*
* @param acquire whether to also acquire this Entry
* @return whether this Entry was enabled
*/
abstract boolean tryEnable(boolean acquire);
/**
* Tries to acquire this Entry.
*
* @return whether this Entry was acquired
*/
abstract boolean tryAcquire();
/**
* Tries to release this Entry.
*
* @return true if this Entry was released,
* false if {@link #tryRemove()} should be called.
*/
abstract boolean tryRelease();
/**
* Tries to remove the entry by marking it as closed.
*
* @return whether the entry can be removed from the containing pool
*/
abstract boolean tryRemove();
/**
* @return whether this Entry is closed
*/
public abstract boolean isClosed();
/**
* @return whether this Entry is reserved
*/
public abstract boolean isReserved();
/**
* @return whether this Entry is idle
*/
public abstract boolean isIdle();
/**
* @return whether this entry is in use.
*/
public abstract boolean isInUse();
/**
* @return whether this entry has been used beyond {@link #getMaxUsageCount()}
* @deprecated MaxUsage functionalities will be removed
*/
@Deprecated
public boolean isOverUsed()
{
return false;
}
boolean isIdleAndOverUsed()
{
return false;
}
// Only for testing.
int getUsageCount()
{
return 0;
}
// Only for testing.
void setUsageCount(int usageCount)
{
}
}
/**
* A Pool entry that holds metadata and a pooled object,
* that can only be acquired concurrently at most once, and
* can be acquired/released multiple times.
*/
private class MonoEntry extends Entry
{
// MIN_VALUE => pending; -1 => closed; 0 => idle; 1 => active;
private final AtomicInteger state = new AtomicInteger(Integer.MIN_VALUE);
@Override
protected boolean tryEnable(boolean acquire)
{
return state.compareAndSet(Integer.MIN_VALUE, acquire ? 1 : 0);
}
@Override
boolean tryAcquire()
{
while (true)
{
int s = state.get();
if (s != 0)
return false;
if (state.compareAndSet(s, 1))
return true;
}
}
@Override
boolean tryRelease()
{
while (true)
{
int s = state.get();
if (s < 0)
return false;
if (s == 0)
throw new IllegalStateException("Cannot release an already released entry");
if (state.compareAndSet(s, 0))
return true;
}
}
@Override
boolean tryRemove()
{
state.set(-1);
return true;
}
@Override
public boolean isClosed()
{
return state.get() < 0;
}
@Override
public boolean isReserved()
{
return state.get() == Integer.MIN_VALUE;
}
@Override
public boolean isIdle()
{
return state.get() == 0;
}
@Override
public boolean isInUse()
{
return state.get() == 1;
}
@Override
public String toString()
{
String s;
switch (state.get())
{
case Integer.MIN_VALUE:
s = "PENDING";
break;
case -1:
s = "CLOSED";
break;
case 0:
s = "IDLE";
break;
default:
s = "ACTIVE";
}
return String.format("%s@%x{%s,pooled=%s}",
getClass().getSimpleName(),
hashCode(),
s,
getPooled());
}
}
/**
* A Pool entry that holds metadata and a pooled object,
* that can be acquired concurrently multiple times, and
* can be acquired/released multiple times.
*/
class MultiEntry extends Entry
{
// hi: MIN_VALUE => pending; -1 => closed; 0+ => usage counter;
// lo: 0 => idle; positive => multiplex counter
private final AtomicBiInteger state;
MultiEntry()
{
this.state = new AtomicBiInteger(Integer.MIN_VALUE, 0);
}
@Override
void setUsageCount(int usageCount)
{
this.state.getAndSetHi(usageCount);
}
@Override
protected boolean tryEnable(boolean acquire)
{
int usage = acquire ? 1 : 0;
return state.compareAndSet(Integer.MIN_VALUE, usage, 0, usage);
}
/**
* Tries to acquire the entry if possible by incrementing both the usage
* count and the multiplex count.
*
* @return true if the usage count is less than {@link #getMaxUsageCount()} and
* the multiplex count is less than {@link #getMaxMultiplex(Object)} and
* the entry is not closed, false otherwise.
*/
@Override
boolean tryAcquire()
{
while (true)
{
long encoded = state.get();
int usageCount = AtomicBiInteger.getHi(encoded);
int multiplexCount = AtomicBiInteger.getLo(encoded);
boolean closed = usageCount < 0;
if (closed)
return false;
T pooled = getPooled();
int maxUsageCount = getMaxUsageCount(pooled);
int maxMultiplexed = getMaxMultiplex(pooled);
if (maxMultiplexed > 0 && multiplexCount >= maxMultiplexed)
return false;
if (maxUsageCount > 0 && usageCount >= maxUsageCount)
return false;
// Prevent overflowing the usage counter by capping it at Integer.MAX_VALUE.
int newUsageCount = usageCount == Integer.MAX_VALUE ? Integer.MAX_VALUE : usageCount + 1;
if (state.compareAndSet(encoded, newUsageCount, multiplexCount + 1))
return true;
}
}
/**
* Tries to release the entry if possible by decrementing the multiplex
* count unless the entity is closed.
*
* @return true if the entry was released,
* false if {@link #tryRemove()} should be called.
*/
@Override
boolean tryRelease()
{
int newMultiplexCount;
int usageCount;
while (true)
{
long encoded = state.get();
usageCount = AtomicBiInteger.getHi(encoded);
boolean closed = usageCount < 0;
if (closed)
return false;
newMultiplexCount = AtomicBiInteger.getLo(encoded) - 1;
if (newMultiplexCount < 0)
throw new IllegalStateException("Cannot release an already released entry");
if (state.compareAndSet(encoded, usageCount, newMultiplexCount))
break;
}
int currentMaxUsageCount = getMaxUsageCount(getPooled());
boolean overUsed = currentMaxUsageCount > 0 && usageCount >= currentMaxUsageCount;
return !(overUsed && newMultiplexCount == 0);
}
/**
* Tries to remove the entry by marking it as closed and decrementing the multiplex counter.
* The multiplex counter will never go below zero and if it reaches zero, the entry is considered removed.
*
* @return true if the entry can be removed from the containing pool, false otherwise.
*/
@Override
boolean tryRemove()
{
while (true)
{
long encoded = state.get();
int usageCount = AtomicBiInteger.getHi(encoded);
int multiplexCount = AtomicBiInteger.getLo(encoded);
int newMultiplexCount = Math.max(multiplexCount - 1, 0);
boolean removed = state.compareAndSet(usageCount, -1, multiplexCount, newMultiplexCount);
if (removed)
return newMultiplexCount == 0;
}
}
@Override
public boolean isClosed()
{
return state.getHi() < 0;
}
@Override
public boolean isReserved()
{
return state.getHi() == Integer.MIN_VALUE;
}
@Override
public boolean isIdle()
{
long encoded = state.get();
return AtomicBiInteger.getHi(encoded) >= 0 && AtomicBiInteger.getLo(encoded) == 0;
}
@Override
public boolean isInUse()
{
long encoded = state.get();
return AtomicBiInteger.getHi(encoded) >= 0 && AtomicBiInteger.getLo(encoded) > 0;
}
@Override
public boolean isOverUsed()
{
int maxUsageCount = getMaxUsageCount();
int usageCount = state.getHi();
return maxUsageCount > 0 && usageCount >= maxUsageCount;
}
@Override
boolean isIdleAndOverUsed()
{
int maxUsageCount = getMaxUsageCount();
long encoded = state.get();
int usageCount = AtomicBiInteger.getHi(encoded);
int multiplexCount = AtomicBiInteger.getLo(encoded);
return maxUsageCount > 0 && usageCount >= maxUsageCount && multiplexCount == 0;
}
@Override
int getUsageCount()
{
return Math.max(state.getHi(), 0);
}
@Override
public String toString()
{
long encoded = state.get();
int usageCount = AtomicBiInteger.getHi(encoded);
int multiplexCount = AtomicBiInteger.getLo(encoded);
String state = usageCount < 0
? (usageCount == Integer.MIN_VALUE ? "PENDING" : "CLOSED")
: (multiplexCount == 0 ? "IDLE" : "ACTIVE");
return String.format("%s@%x{%s,usage=%d,multiplex=%d,pooled=%s}",
getClass().getSimpleName(),
hashCode(),
state,
Math.max(usageCount, 0),
Math.max(multiplexCount, 0),
getPooled());
}
}
}
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