Package org.apache.tomcat.dbcp.pool2

Interface PooledObject<T>

Type Parameters:
T - the type of object in the pool
All Superinterfaces:
Comparable<PooledObject<T>>
All Known Implementing Classes:
DefaultPooledObject, PooledSoftReference
public interface PooledObject<T> extends Comparable<PooledObject<T>>
Defines the wrapper that is used to track the additional information, such as state, for the pooled objects.

Implementations of this class are required to be thread-safe.

Since:
2.0

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    allocate()
    Allocates the object.
    int
    compareTo(PooledObject<T> other)
    Orders instances based on idle time - i.e. the length of time since the instance was returned to the pool.
    boolean
    deallocate()
    Deallocates the object and sets it IDLE if it is currently ALLOCATED.
    boolean
    endEvictionTest(Deque<PooledObject<T>> idleQueue)
    Called to inform the object that the eviction test has ended.
    boolean
    equals(Object obj)
     
    long
    getActiveTimeMillis()
    Obtains the time in milliseconds that this object last spent in the active state (it may still be active in which case subsequent calls will return an increased value).
    long
    getBorrowedCount()
    Gets the number of times this object has been borrowed.
    long
    getCreateTime()
    Obtains the time (using the same basis as System.currentTimeMillis()) that this object was created.
    long
    getIdleTimeMillis()
    Obtains the time in milliseconds that this object last spend in the idle state (it may still be idle in which case subsequent calls will return an increased value).
    long
    getLastBorrowTime()
    Obtains the time the wrapped object was last borrowed.
    long
    getLastReturnTime()
    Obtains the time the wrapped object was last returned.
    long
    getLastUsedTime()
    Returns an estimate of the last time this object was used.
    T
    getObject()
    Obtains the underlying object that is wrapped by this instance of PooledObject.
    PooledObjectState
    getState()
    Returns the state of this object.
    int
    hashCode()
     
    void
    invalidate()
    Sets the state to INVALID
    void
    markAbandoned()
    Marks the pooled object as abandoned.
    void
    markReturning()
    Marks the object as returning to the pool.
    void
    printStackTrace(PrintWriter writer)
    Prints the stack trace of the code that borrowed this pooled object and the stack trace of the last code to use this object (if available) to the supplied writer.
    void
    setLogAbandoned(boolean logAbandoned)
    Is abandoned object tracking being used?
    void
    setRequireFullStackTrace(boolean requireFullStackTrace)
    Configures the stack trace generation strategy based on whether or not fully detailed stack traces are required.
    boolean
    startEvictionTest()
    Attempts to place the pooled object in the PooledObjectState.EVICTION state.
    String
    toString()
    Provides a String form of the wrapper for debug purposes.
    void
    use()
    Record the current stack trace as the last time the object was used.

  • Method Details

    • getObject

      T getObject()
      Obtains the underlying object that is wrapped by this instance of PooledObject.
      Returns:
      The wrapped object

    • getCreateTime

      long getCreateTime()
      Obtains the time (using the same basis as System.currentTimeMillis()) that this object was created.
      Returns:
      The creation time for the wrapped object

    • getActiveTimeMillis

      long getActiveTimeMillis()
      Obtains the time in milliseconds that this object last spent in the active state (it may still be active in which case subsequent calls will return an increased value).
      Returns:
      The time in milliseconds last spent in the active state

    • getBorrowedCount

      long getBorrowedCount()
      Gets the number of times this object has been borrowed.
      Returns:
      The number of times this object has been borrowed.
      Since:
      2.7.0

    • getIdleTimeMillis

      long getIdleTimeMillis()
      Obtains the time in milliseconds that this object last spend in the idle state (it may still be idle in which case subsequent calls will return an increased value).
      Returns:
      The time in milliseconds last spent in the idle state

    • getLastBorrowTime

      long getLastBorrowTime()
      Obtains the time the wrapped object was last borrowed.
      Returns:
      The time the object was last borrowed

    • getLastReturnTime

      long getLastReturnTime()
      Obtains the time the wrapped object was last returned.
      Returns:
      The time the object was last returned

    • getLastUsedTime

      long getLastUsedTime()
      Returns an estimate of the last time this object was used. If the class of the pooled object implements TrackedUse, what is returned is the maximum of TrackedUse.getLastUsed() and getLastBorrowTime(); otherwise this method gives the same value as getLastBorrowTime().
      Returns:
      the last time this object was used

    • compareTo

      int compareTo(PooledObject<T> other)
      Orders instances based on idle time - i.e. the length of time since the instance was returned to the pool. Used by the GKOP idle object evictor.

      Note: This class has a natural ordering that is inconsistent with equals if distinct objects have the same identity hash code.

      Specified by:
      compareTo in interface Comparable<T>

    • equals

      boolean equals(Object obj)
      Overrides:
      equals in class Object

    • hashCode

      int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      String toString()
      Provides a String form of the wrapper for debug purposes. The format is not fixed and may change at any time.

      Overrides:
      toString in class Object

    • startEvictionTest

      boolean startEvictionTest()
      Attempts to place the pooled object in the PooledObjectState.EVICTION state.
      Returns:
      true if the object was placed in the PooledObjectState.EVICTION state otherwise false

    • endEvictionTest

      boolean endEvictionTest(Deque<PooledObject<T>> idleQueue)
      Called to inform the object that the eviction test has ended.
      Parameters:
      idleQueue - The queue of idle objects to which the object should be returned
      Returns:
      Currently not used

    • allocate

      boolean allocate()
      Allocates the object.
      Returns:
      true if the original state was IDLE

    • deallocate

      boolean deallocate()
      Deallocates the object and sets it IDLE if it is currently ALLOCATED.
      Returns:
      true if the state was ALLOCATED

    • invalidate

      void invalidate()
      Sets the state to INVALID

    • setLogAbandoned

      void setLogAbandoned(boolean logAbandoned)
      Is abandoned object tracking being used? If this is true the implementation will need to record the stack trace of the last caller to borrow this object.
      Parameters:
      logAbandoned - The new configuration setting for abandoned object tracking

    • setRequireFullStackTrace

      void setRequireFullStackTrace(boolean requireFullStackTrace)
      Configures the stack trace generation strategy based on whether or not fully detailed stack traces are required. When set to false, abandoned logs may only include caller class information rather than method names, line numbers, and other normal metadata available in a full stack trace.
      Parameters:
      requireFullStackTrace - the new configuration setting for abandoned object logging
      Since:
      2.7.0

    • use

      void use()
      Record the current stack trace as the last time the object was used.

    • printStackTrace

      void printStackTrace(PrintWriter writer)
      Prints the stack trace of the code that borrowed this pooled object and the stack trace of the last code to use this object (if available) to the supplied writer.
      Parameters:
      writer - The destination for the debug output

    • getState

      PooledObjectState getState()
      Returns the state of this object.
      Returns:
      state

    • markAbandoned

      void markAbandoned()
      Marks the pooled object as abandoned.

    • markReturning

      void markReturning()
      Marks the object as returning to the pool.