org.springframework.aop.target

## Class HotSwappableTargetSource

- java.lang.Object
- - org.springframework.aop.target.HotSwappableTargetSource

- All Implemented Interfaces:
    Serializable, TargetClassAware, TargetSource

      public class HotSwappableTargetSource
      extends Object
      implements TargetSource, Serializable

  `TargetSource` implementation that caches a local target object, but allows the target to be swapped while the application is running.

  If configuring an object of this class in a Spring IoC container, use constructor injection.

  This TargetSource is serializable if the target is at the time of serialization.

  Author:
    Rod Johnson, Juergen Hoeller
  See Also:
    Serialized Form

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `HotSwappableTargetSource(Object initialTarget)` Create a new HotSwappableTargetSource with the given initial target object.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `equals(Object other)` Two HotSwappableTargetSources are equal if the current target objects are equal.
    `Object` | `getTarget()` Return a target instance.
    `Class<?>` | `getTargetClass()` Return the type of the current target object.
    `int` | `hashCode()`
    `boolean` | `isStatic()` Will all calls to `TargetSource.getTarget()` return the same object?
    `void` | `releaseTarget(Object target)` Release the given target object obtained from the `TargetSource.getTarget()` method.
    `Object` | `swap(Object newTarget)` Swap the target, returning the old target object.
    `String` | `toString()`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### HotSwappableTargetSource

          public HotSwappableTargetSource(Object initialTarget)

      Create a new HotSwappableTargetSource with the given initial target object.
      Parameters:
        `initialTarget` - the initial target object

  - ### Method Detail

    - #### getTargetClass

          public Class<?> getTargetClass()

      Return the type of the current target object.

      The returned type should usually be constant across all target objects.

      Specified by:
        `getTargetClass` in interface `TargetClassAware`
      Specified by:
        `getTargetClass` in interface `TargetSource`
      Returns:
        the type of targets returned by this `TargetSource`

    - #### isStatic

          public final boolean isStatic()

      Description copied from interface: `TargetSource`
      Will all calls to `TargetSource.getTarget()` return the same object?

      In that case, there will be no need to invoke `TargetSource.releaseTarget(Object)`, and the AOP framework can cache the return value of `TargetSource.getTarget()`.

      Specified by:
        `isStatic` in interface `TargetSource`
      Returns:
        `true` if the target is immutable
      See Also:
        `TargetSource.getTarget()`

    - #### getTarget

          public Object getTarget()

      Description copied from interface: `TargetSource`
      Return a target instance. Invoked immediately before the AOP framework calls the "target" of an AOP method invocation.
      Specified by:
        `getTarget` in interface `TargetSource`
      Returns:
        the target object, which contains the joinpoint

    - #### releaseTarget

          public void releaseTarget(Object target)

      Description copied from interface: `TargetSource`
      Release the given target object obtained from the `TargetSource.getTarget()` method.
      Specified by:
        `releaseTarget` in interface `TargetSource`
      Parameters:
        `target` - object obtained from a call to `TargetSource.getTarget()`

    - #### swap

          public Object swap(Object newTarget)
                      throws IllegalArgumentException

      Swap the target, returning the old target object.
      Parameters:
        `newTarget` - the new target object
      Returns:
        the old target object
      Throws:
        `IllegalArgumentException` - if the new target is invalid

    - #### equals

          public boolean equals(Object other)

      Two HotSwappableTargetSources are equal if the current target objects are equal.
      Overrides:
        `equals` in class `Object`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `Object`

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`