Package org.apache.tomcat.dbcp.pool2

Class PoolUtils

java.lang.Object

org.apache.tomcat.dbcp.pool2.PoolUtils

public final class PoolUtils
extends Object

This class consists exclusively of static methods that operate on or return ObjectPool or KeyedObjectPool related interfaces.

Since:

2.0

Field Summary

Fields

Modifier and Type	Field	Description
static final String	MSG_NULL_KEY
static final String	MSG_NULL_KEYS

Constructor Summary

Constructors

Constructor	Description
PoolUtils()	PoolUtils instances should NOT be constructed in standard programming.

Method Summary

Modifier and Type	Method	Description
static <K, V> Map<K,TimerTask>	checkMinIdle(KeyedObjectPool<K,V> keyedPool, Collection<K> keys, int minIdle, long period)	Periodically check the idle object count for each key in the Collection keys in the keyedPool.
static <K, V> TimerTask	checkMinIdle(KeyedObjectPool<K,V> keyedPool, K key, int minIdle, long period)	Periodically check the idle object count for the key in the keyedPool.
static <T> TimerTask	checkMinIdle(ObjectPool<T> pool, int minIdle, long period)	Periodically check the idle object count for the pool.
static void	checkRethrow(Throwable t)	Should the supplied Throwable be re-thrown (eg if it is an instance of one of the Throwables that should never be swallowed).
static <K, V> void	prefill(KeyedObjectPool<K,V> keyedPool, Collection<K> keys, int count)	Deprecated. Use KeyedObjectPool.addObjects(Collection, int).
static <K, V> void	prefill(KeyedObjectPool<K,V> keyedPool, K key, int count)	Deprecated. Use KeyedObjectPool.addObjects(Object, int).
static <T> void	prefill(ObjectPool<T> pool, int count)	Deprecated. Use ObjectPool.addObjects(int).
static <K, V> KeyedPooledObjectFactory<K,V>	synchronizedKeyedPooledFactory(KeyedPooledObjectFactory<K,V> keyedFactory)	Returns a synchronized (thread-safe) KeyedPooledObjectFactory backed by the specified KeyedPoolableObjectFactory.
static <T> PooledObjectFactory<T>	synchronizedPooledFactory(PooledObjectFactory<T> factory)	Returns a synchronized (thread-safe) PooledObjectFactory backed by the specified PooledObjectFactory.

Methods inherited from class java.lang.Object

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

Field Details

MSG_NULL_KEY

public static final String MSG_NULL_KEY

See Also:

• Constant Field Values

MSG_NULL_KEYS

public static final String MSG_NULL_KEYS

See Also:

• Constant Field Values

Constructor Details

PoolUtils

public PoolUtils()

PoolUtils instances should NOT be constructed in standard programming. Instead, the class should be used procedurally: PoolUtils.adapt(aPool);. This constructor is public to permit tools that require a JavaBean instance to operate.

Method Details

checkRethrow

public static void checkRethrow(Throwable t)

Should the supplied Throwable be re-thrown (eg if it is an instance of one of the Throwables that should never be swallowed). Used by the pool error handling for operations that throw exceptions that normally need to be ignored.

Parameters:

t - The Throwable to check

Throws:

ThreadDeath - if that is passed in

VirtualMachineError - if that is passed in

checkMinIdle

public static <T> TimerTask checkMinIdle(ObjectPool<T> pool,
 int minIdle,
 long period)
                                  throws IllegalArgumentException

Periodically check the idle object count for the pool. At most one idle object will be added per period. If there is an exception when calling ObjectPool.addObject() then no more checks will be performed.

Type Parameters:

T - the type of objects in the pool

Parameters:

pool - the pool to check periodically.

minIdle - if the ObjectPool.getNumIdle() is less than this then add an idle object.

period - the frequency to check the number of idle objects in a pool, see Timer.schedule(TimerTask, long, long).

Returns:

the TimerTask that will periodically check the pools idle object count.

Throws:

IllegalArgumentException - when pool is null or when minIdle is negative or when period isn't valid for Timer.schedule(TimerTask, long, long)

checkMinIdle

public static <K,
V> TimerTask checkMinIdle(KeyedObjectPool<K,V> keyedPool,
 K key,
 int minIdle,
 long period)
                                    throws IllegalArgumentException

Periodically check the idle object count for the key in the keyedPool. At most one idle object will be added per period. If there is an exception when calling KeyedObjectPool.addObject(Object) then no more checks for that key will be performed.

Type Parameters:

K - the type of the pool key

V - the type of pool entries

Parameters:

keyedPool - the keyedPool to check periodically.

key - the key to check the idle count of.

minIdle - if the KeyedObjectPool.getNumIdle(Object) is less than this then add an idle object.

period - the frequency to check the number of idle objects in a keyedPool, see Timer.schedule(TimerTask, long, long).

Returns:

the TimerTask that will periodically check the pools idle object count.

Throws:

IllegalArgumentException - when keyedPool, key is null or when minIdle is negative or when period isn't valid for Timer.schedule(TimerTask, long, long).

checkMinIdle

public static <K,
V> Map<K,TimerTask> checkMinIdle(KeyedObjectPool<K,V> keyedPool,
 Collection<K> keys,
 int minIdle,
 long period)
                                           throws IllegalArgumentException

Periodically check the idle object count for each key in the Collection keys in the keyedPool. At most one idle object will be added per period.

Type Parameters:

K - the type of the pool key

V - the type of pool entries

Parameters:

keyedPool - the keyedPool to check periodically.

keys - a collection of keys to check the idle object count.

minIdle - if the KeyedObjectPool.getNumIdle(Object) is less than this then add an idle object.

period - the frequency to check the number of idle objects in a keyedPool, see Timer.schedule(TimerTask, long, long).

Returns:

a Map of key and TimerTask pairs that will periodically check the pools idle object count.

Throws:

IllegalArgumentException - when keyedPool, keys, or any of the values in the collection is null or when minIdle is negative or when period isn't valid for Timer.schedule(TimerTask, long, long).

See Also:

• checkMinIdle(KeyedObjectPool, Object, int, long)

prefill

@Deprecated
public static <T> void prefill(ObjectPool<T> pool,
 int count)
                        throws Exception,
IllegalArgumentException

Deprecated.

Use ObjectPool.addObjects(int).

Calls ObjectPool.addObject() on pool count number of times.

Type Parameters:

T - the type of objects in the pool

Parameters:

pool - the pool to prefill.

count - the number of idle objects to add.

Throws:

Exception - when ObjectPool.addObject() fails.

IllegalArgumentException - when pool is null.

prefill

@Deprecated
public static <K,
V> void prefill(KeyedObjectPool<K,V> keyedPool,
 K key,
 int count)
                          throws Exception,
IllegalArgumentException

Deprecated.

Use KeyedObjectPool.addObjects(Object, int).

Calls KeyedObjectPool.addObject(Object) on keyedPool with key count number of times.

Type Parameters:

K - the type of the pool key

V - the type of pool entries

Parameters:

keyedPool - the keyedPool to prefill.

key - the key to add objects for.

count - the number of idle objects to add for key.

Throws:

Exception - when KeyedObjectPool.addObject(Object) fails.

IllegalArgumentException - when keyedPool or key is null.

prefill

@Deprecated
public static <K,
V> void prefill(KeyedObjectPool<K,V> keyedPool,
 Collection<K> keys,
 int count)
                          throws Exception,
IllegalArgumentException

Deprecated.

Use KeyedObjectPool.addObjects(Collection, int).

Calls KeyedObjectPool.addObject(Object) on keyedPool with each key in keys for count number of times. This has the same effect as calling prefill(KeyedObjectPool, Object, int) for each key in the keys collection.

Type Parameters:

K - the type of the pool key

V - the type of pool entries

Parameters:

keyedPool - the keyedPool to prefill.

keys - Collection of keys to add objects for.

count - the number of idle objects to add for each key.

Throws:

Exception - when KeyedObjectPool.addObject(Object) fails.

IllegalArgumentException - when keyedPool, keys, or any value in keys is null.

See Also:

• prefill(KeyedObjectPool, Object, int)

synchronizedPooledFactory

public static <T> PooledObjectFactory<T> synchronizedPooledFactory(PooledObjectFactory<T> factory)

Returns a synchronized (thread-safe) PooledObjectFactory backed by the specified PooledObjectFactory.

Type Parameters:

T - the type of objects in the pool

Parameters:

factory - the PooledObjectFactory to be "wrapped" in a synchronized PooledObjectFactory.

Returns:

a synchronized view of the specified PooledObjectFactory.

synchronizedKeyedPooledFactory

public static <K,
V> KeyedPooledObjectFactory<K,V> synchronizedKeyedPooledFactory(KeyedPooledObjectFactory<K,V> keyedFactory)

Returns a synchronized (thread-safe) KeyedPooledObjectFactory backed by the specified KeyedPoolableObjectFactory.

Type Parameters:

K - the type of the pool key

V - the type of pool entries

Parameters:

keyedFactory - the KeyedPooledObjectFactory to be "wrapped" in a synchronized KeyedPooledObjectFactory.

Returns:

a synchronized view of the specified KeyedPooledObjectFactory.