KeyedObjectPool

类型参数:

K - The type of keys maintained by this pool.

V - Type of element pooled in this pool.

所有超级接口:

java.lang.AutoCloseable, java.io.Closeable

所有已知实现类:

GenericKeyedObjectPool, ProxiedKeyedObjectPool
```
public interface KeyedObjectPool<K,V>
extends java.io.Closeable
```
A "keyed" pooling interface.
A keyed pool maintains a pool of instances for each key value.

Example of use:
```
 Object obj = null;
 Object key = "Key";

 try {
     obj = pool.borrowObject(key);
     //...use the object...
 } catch(Exception e) {
     // invalidate the object
     pool.invalidateObject(key, obj);
     // do not return the object to the pool twice
     obj = null;
 } finally {
     // make sure the object is returned to the pool
     if(null != obj) {
         pool.returnObject(key, obj);
     }
 }
```
KeyedObjectPool implementations may choose to store at most one instance per key value, or may choose to maintain a pool of instances for each key (essentially creating a Map of pools).

See GenericKeyedObjectPool for an implementation.
从以下版本开始:

2.0

另请参阅:

KeyedPooledObjectFactory, ObjectPool, GenericKeyedObjectPool

方法概要

所有方法实例方法抽象方法默认方法
限定符和类型	方法和说明
`void`	`addObject(K key)` Create an object using the `factory` or other implementation dependent mechanism, passivate it, and then place it in the idle object pool.
`default void`	`addObjects(java.util.Collection<K> keys, int count)` Calls `addObject(Object)` with each key in `keys` for `count` number of times.
`default void`	`addObjects(K key, int count)` Calls `addObject(Object)` `key` `count` number of times.
`V`	`borrowObject(K key)` Borrows an instance from this pool for the specified `key`.
`void`	`clear()` Clears the pool, removing all pooled instances (optional operation).
`void`	`clear(K key)` Clears the specified pool, removing all pooled instances corresponding to the given `key` (optional operation).
`void`	`close()` Close this pool, and free any resources associated with it.
`int`	`getNumActive()` Gets the total number of instances currently borrowed from this pool but not yet returned.
`int`	`getNumActive(K key)` Gets the number of instances currently borrowed from but not yet returned to the pool corresponding to the given `key`.
`int`	`getNumIdle()` Gets the total number of instances currently idle in this pool.
`int`	`getNumIdle(K key)` Gets the number of instances corresponding to the given `key` currently idle in this pool.
`void`	`invalidateObject(K key, V obj)` Invalidates an object from the pool.
`default void`	`invalidateObject(K key, V obj, DestroyMode mode)` Invalidates an object from the pool, using the provided `DestroyMode`.
`void`	`returnObject(K key, V obj)` Return an instance to the pool.

- 方法详细资料
  - addObject
```
void addObject(K key)
        throws java.lang.Exception,
               java.lang.IllegalStateException,
               java.lang.UnsupportedOperationException
```
    Create an object using the factory or other implementation dependent mechanism, passivate it, and then place it in the idle object pool. addObject is useful for "pre-loading" a pool with idle objects (Optional operation).
    
    参数:
    
    key - the key a new instance should be added to
    
    抛出:
    
    java.lang.Exception - when KeyedPooledObjectFactory.makeObject(K) fails.
    
    java.lang.IllegalStateException - after close() has been called on this pool.
    
    java.lang.UnsupportedOperationException - when this pool cannot add new idle objects.
  - addObjects
```
default void addObjects(java.util.Collection<K> keys,
                        int count)
                 throws java.lang.Exception,
                        java.lang.IllegalArgumentException
```
    Calls addObject(Object) with each key in keys for count number of times. This has the same effect as calling addObjects(Object, int) for each key in the keys collection.
    
    参数:
    
    keys - Collection of keys to add objects for.
    
    count - the number of idle objects to add for each key.
    
    抛出:
    
    java.lang.Exception - when addObject(Object) fails.
    
    java.lang.IllegalArgumentException - when keyedPool, keys, or any value in keys is null.
    
    另请参阅:
    
    addObjects(Object, int)
  - addObjects
```
default void addObjects(K key,
                        int count)
                 throws java.lang.Exception,
                        java.lang.IllegalArgumentException
```
    Calls addObject(Object) key count number of times.
    
    参数:
    
    key - the key to add objects for.
    
    count - the number of idle objects to add for key.
    
    抛出:
    
    java.lang.Exception - when addObject(Object) fails.
    
    java.lang.IllegalArgumentException - when key is null.
    
    从以下版本开始:
    
    2.8.0
  - borrowObject
```
V borrowObject(K key)
        throws java.lang.Exception,
               java.util.NoSuchElementException,
               java.lang.IllegalStateException
```
    Borrows an instance from this pool for the specified key.
    Instances returned from this method will have been either newly created with makeObject or will be a previously idle object and have been activated with activateObject and then (optionally) validated with validateObject.
    
    By contract, clients must return the borrowed object using returnObject, invalidateObject, or a related method as defined in an implementation or sub-interface, using a key that is equivalent to the one used to borrow the instance in the first place.
    
    The behavior of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations).
    
    参数:
    
    key - the key used to obtain the object
    
    返回:
    
    an instance from this pool.
    
    抛出:
    
    java.lang.IllegalStateException - after close has been called on this pool
    
    java.lang.Exception - when makeObject throws an exception
    
    java.util.NoSuchElementException - when the pool is exhausted and cannot or will not return another instance
  - clear
```
void clear()
    throws java.lang.Exception,
           java.lang.UnsupportedOperationException
```
    Clears the pool, removing all pooled instances (optional operation).
    
    抛出:
    
    java.lang.UnsupportedOperationException - when this implementation doesn't support the operation
    
    java.lang.Exception - if the pool cannot be cleared
  - clear
```
void clear(K key)
    throws java.lang.Exception,
           java.lang.UnsupportedOperationException
```
    Clears the specified pool, removing all pooled instances corresponding to the given key (optional operation).
    
    参数:
    
    key - the key to clear
    
    抛出:
    
    java.lang.UnsupportedOperationException - when this implementation doesn't support the operation
    
    java.lang.Exception - if the key cannot be cleared
  - close
```
void close()
```
    Close this pool, and free any resources associated with it.
    Calling addObject or borrowObject after invoking this method on a pool will cause them to throw an IllegalStateException.
    
    Implementations should silently fail if not all resources can be freed.
    
    指定者:
    
    close 在接口中 java.lang.AutoCloseable
    
    指定者:
    
    close 在接口中 java.io.Closeable
  - getNumActive
```
int getNumActive()
```
    Gets the total number of instances currently borrowed from this pool but not yet returned. Returns a negative value if this information is not available.
    
    返回:
    
    the total number of instances currently borrowed from this pool but not yet returned.
  - getNumActive
```
int getNumActive(K key)
```
    Gets the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key. Returns a negative value if this information is not available.
    
    参数:
    
    key - the key to query
    
    返回:
    
    the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key.
  - getNumIdle
```
int getNumIdle()
```
    Gets the total number of instances currently idle in this pool. Returns a negative value if this information is not available.
    
    返回:
    
    the total number of instances currently idle in this pool.
  - getNumIdle
```
int getNumIdle(K key)
```
    Gets the number of instances corresponding to the given key currently idle in this pool. Returns a negative value if this information is not available.
    
    参数:
    
    key - the key to query
    
    返回:
    
    the number of instances corresponding to the given key currently idle in this pool.
  - invalidateObject
```
void invalidateObject(K key,
                      V obj)
               throws java.lang.Exception
```
    Invalidates an object from the pool.
    By contract, obj must have been obtained using borrowObject or a related method as defined in an implementation or sub-interface using a key that is equivalent to the one used to borrow the Object in the first place.
    
    This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.
    
    参数:
    
    key - the key used to obtain the object
    
    obj - a borrowed instance to be returned.
    
    抛出:
    
    java.lang.Exception - if the instance cannot be invalidated
  - invalidateObject
```
default void invalidateObject(K key,
                              V obj,
                              DestroyMode mode)
                       throws java.lang.Exception
```
    Invalidates an object from the pool, using the provided DestroyMode.
    By contract, obj must have been obtained using borrowObject or a related method as defined in an implementation or sub-interface using a key that is equivalent to the one used to borrow the Object in the first place.
    
    This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.
    
    参数:
    
    key - the key used to obtain the object
    
    obj - a borrowed instance to be returned.
    
    mode - destroy activation context provided to the factory
    
    抛出:
    
    java.lang.Exception - if the instance cannot be invalidated
    
    从以下版本开始:
    
    2.9.0
  - returnObject
```
void returnObject(K key,
                  V obj)
           throws java.lang.Exception
```
    Return an instance to the pool. By contract, obj must have been obtained using borrowObject or a related method as defined in an implementation or sub-interface using a key that is equivalent to the one used to borrow the instance in the first place.
    
    参数:
    
    key - the key used to obtain the object
    
    obj - a borrowed instance to be returned.
    
    抛出:
    
    java.lang.IllegalStateException - if an attempt is made to return an object to the pool that is in any state other than allocated (i.e. borrowed). Attempting to return an object more than once or attempting to return an object that was never borrowed from the pool will trigger this exception.
    
    java.lang.Exception - if an instance cannot be returned to the pool

接口 KeyedObjectPool<K,V>

方法概要

方法详细资料

addObject

addObjects

addObjects

borrowObject

clear

clear

close

getNumActive

getNumActive

getNumIdle

getNumIdle

invalidateObject

invalidateObject

returnObject