LifecycleBase (Apache Tomcat 9.0.37 API Documentation)

org.apache.catalina.util

## Class LifecycleBase

- java.lang.Object
- - org.apache.catalina.util.LifecycleBase

- All Implemented Interfaces:
    Lifecycle
  Direct Known Subclasses:
    AbstractResourceSet, EmptyResourceSet, LifecycleMBeanBase, SessionIdGeneratorBase, StandardPipeline, StoreBase

      public abstract class LifecycleBase
      extends Object
      implements Lifecycle

  Base implementation of the `Lifecycle` interface that implements the state transition rules for `Lifecycle.start()` and `Lifecycle.stop()`

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle

      `Lifecycle.SingleUse`

  - ### Field Summary

    - ### Fields inherited from interface org.apache.catalina.Lifecycle

      `AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `LifecycleBase()`

  - ### Method Summary

    All Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `addLifecycleListener(LifecycleListener listener)` Add a LifecycleEvent listener to this component.
    `void` | `destroy()` Prepare to discard the object.
    `protected abstract void` | `destroyInternal()` Sub-classes implement this method to perform any instance destruction required.
    `LifecycleListener[]` | `findLifecycleListeners()` Get the life cycle listeners associated with this life cycle.
    `protected void` | `fireLifecycleEvent(String type, Object data)` Allow sub classes to fire `Lifecycle` events.
    `LifecycleState` | `getState()` Obtain the current state of the source component.
    `String` | `getStateName()` Obtain a textual representation of the current component state.
    `boolean` | `getThrowOnFailure()` Will a `LifecycleException` thrown by a sub-class during `initInternal()`, `startInternal()`, `stopInternal()` or `destroyInternal()` be re-thrown for the caller to handle or will it be logged instead?
    `void` | `init()` Prepare the component for starting.
    `protected abstract void` | `initInternal()` Sub-classes implement this method to perform any instance initialisation required.
    `void` | `removeLifecycleListener(LifecycleListener listener)` Remove a LifecycleEvent listener from this component.
    `protected void` | `setState(LifecycleState state)` Provides a mechanism for sub-classes to update the component state.
    `protected void` | `setState(LifecycleState state, Object data)` Provides a mechanism for sub-classes to update the component state.
    `void` | `setThrowOnFailure(boolean throwOnFailure)` Configure if a `LifecycleException` thrown by a sub-class during `initInternal()`, `startInternal()`, `stopInternal()` or `destroyInternal()` will be re-thrown for the caller to handle or if it will be logged instead.
    `void` | `start()` Prepare for the beginning of active use of the public methods other than property getters/setters and life cycle methods of this component.
    `protected abstract void` | `startInternal()` Sub-classes must ensure that the state is changed to `LifecycleState.STARTING` during the execution of this method.
    `void` | `stop()` Gracefully terminate the active use of the public methods other than property getters/setters and life cycle methods of this component.
    `protected abstract void` | `stopInternal()` Sub-classes must ensure that the state is changed to `LifecycleState.STOPPING` during the execution of this method.

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

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

- - ### Constructor Detail

    - #### LifecycleBase

          public LifecycleBase()

  - ### Method Detail

    - #### getThrowOnFailure

          public boolean getThrowOnFailure()

      Will a `LifecycleException` thrown by a sub-class during `initInternal()`, `startInternal()`, `stopInternal()` or `destroyInternal()` be re-thrown for the caller to handle or will it be logged instead?
      Returns:
        `true` if the exception will be re-thrown, otherwise `false`

    - #### setThrowOnFailure

          public void setThrowOnFailure(boolean throwOnFailure)

      Configure if a `LifecycleException` thrown by a sub-class during `initInternal()`, `startInternal()`, `stopInternal()` or `destroyInternal()` will be re-thrown for the caller to handle or if it will be logged instead.
      Parameters:
        `throwOnFailure` - `true` if the exception should be re-thrown, otherwise `false`

    - #### addLifecycleListener

          public void addLifecycleListener(LifecycleListener listener)

      Add a LifecycleEvent listener to this component.
      Specified by:
        `addLifecycleListener` in interface `Lifecycle`
      Parameters:
        `listener` - The listener to add

    - #### findLifecycleListeners

          public LifecycleListener[] findLifecycleListeners()

      Get the life cycle listeners associated with this life cycle.
      Specified by:
        `findLifecycleListeners` in interface `Lifecycle`
      Returns:
        An array containing the life cycle listeners associated with this life cycle. If this component has no listeners registered, a zero-length array is returned.

    - #### removeLifecycleListener

          public void removeLifecycleListener(LifecycleListener listener)

      Remove a LifecycleEvent listener from this component.
      Specified by:
        `removeLifecycleListener` in interface `Lifecycle`
      Parameters:
        `listener` - The listener to remove

    - #### fireLifecycleEvent

          protected void fireLifecycleEvent(String type,
                                            Object data)

      Allow sub classes to fire `Lifecycle` events.
      Parameters:
        `type` - Event type
        `data` - Data associated with event.

    - #### init

          public final void init()
                          throws LifecycleException

      Description copied from interface: `Lifecycle`
      Prepare the component for starting. This method should perform any initialization required post object creation. The following `LifecycleEvent`s will be fired in the following order:
      1. INIT_EVENT: On the successful completion of component initialization.
      Specified by:
        `init` in interface `Lifecycle`
      Throws:
        `LifecycleException` - if this component detects a fatal error that prevents this component from being used

    - #### initInternal

          protected abstract void initInternal()
                                        throws LifecycleException

      Sub-classes implement this method to perform any instance initialisation required.
      Throws:
        `LifecycleException` - If the initialisation fails

    - #### start

          public final void start()
                           throws LifecycleException

      Prepare for the beginning of active use of the public methods other than property getters/setters and life cycle methods of this component. This method should be called before any of the public methods other than property getters/setters and life cycle methods of this component are utilized. The following `LifecycleEvent`s will be fired in the following order:
      1. BEFORE_START_EVENT: At the beginning of the method. It is as this point the state transitions to `LifecycleState.STARTING_PREP`.
      2. START_EVENT: During the method once it is safe to call start() for any child components. It is at this point that the state transitions to `LifecycleState.STARTING` and that the public methods other than property getters/setters and life cycle methods may be used.
      3. AFTER_START_EVENT: At the end of the method, immediately before it returns. It is at this point that the state transitions to `LifecycleState.STARTED`.
      Specified by:
        `start` in interface `Lifecycle`
      Throws:
        `LifecycleException` - if this component detects a fatal error that prevents this component from being used

    - #### startInternal

          protected abstract void startInternal()
                                         throws LifecycleException

      Sub-classes must ensure that the state is changed to `LifecycleState.STARTING` during the execution of this method. Changing state will trigger the `Lifecycle.START_EVENT` event. If a component fails to start it may either throw a `LifecycleException` which will cause it's parent to fail to start or it can place itself in the error state in which case `stop()` will be called on the failed component but the parent component will continue to start normally.
      Throws:
        `LifecycleException` - Start error occurred

    - #### stop

          public final void stop()
                          throws LifecycleException

      Gracefully terminate the active use of the public methods other than property getters/setters and life cycle methods of this component. Once the STOP_EVENT is fired, the public methods other than property getters/setters and life cycle methods should not be used. The following `LifecycleEvent`s will be fired in the following order:
      1. BEFORE_STOP_EVENT: At the beginning of the method. It is at this point that the state transitions to `LifecycleState.STOPPING_PREP`.
      2. STOP_EVENT: During the method once it is safe to call stop() for any child components. It is at this point that the state transitions to `LifecycleState.STOPPING` and that the public methods other than property getters/setters and life cycle methods may no longer be used.
      3. AFTER_STOP_EVENT: At the end of the method, immediately before it returns. It is at this point that the state transitions to `LifecycleState.STOPPED`.
      Note that if transitioning from `LifecycleState.FAILED` then the three events above will be fired but the component will transition directly from `LifecycleState.FAILED` to `LifecycleState.STOPPING`, bypassing `LifecycleState.STOPPING_PREP`
      Specified by:
        `stop` in interface `Lifecycle`
      Throws:
        `LifecycleException` - if this component detects a fatal error that needs to be reported

    - #### stopInternal

          protected abstract void stopInternal()
                                        throws LifecycleException

      Sub-classes must ensure that the state is changed to `LifecycleState.STOPPING` during the execution of this method. Changing state will trigger the `Lifecycle.STOP_EVENT` event.
      Throws:
        `LifecycleException` - Stop error occurred

    - #### destroy

          public final void destroy()
                             throws LifecycleException

      Description copied from interface: `Lifecycle`
      Prepare to discard the object. The following `LifecycleEvent`s will be fired in the following order:
      1. DESTROY_EVENT: On the successful completion of component destruction.
      Specified by:
        `destroy` in interface `Lifecycle`
      Throws:
        `LifecycleException` - if this component detects a fatal error that prevents this component from being used

    - #### destroyInternal

          protected abstract void destroyInternal()
                                           throws LifecycleException

      Sub-classes implement this method to perform any instance destruction required.
      Throws:
        `LifecycleException` - If the destruction fails

    - #### getState

          public LifecycleState getState()

      Obtain the current state of the source component.
      Specified by:
        `getState` in interface `Lifecycle`
      Returns:
        The current state of the source component.

    - #### getStateName

          public String getStateName()

      Obtain a textual representation of the current component state. Useful for JMX. The format of this string may vary between point releases and should not be relied upon to determine component state. To determine component state, use `Lifecycle.getState()`.
      Specified by:
        `getStateName` in interface `Lifecycle`
      Returns:
        The name of the current component state.

    - #### setState

          protected void setState(LifecycleState state)
                           throws LifecycleException

      Provides a mechanism for sub-classes to update the component state. Calling this method will automatically fire any associated `Lifecycle` event. It will also check that any attempted state transition is valid for a sub-class.
      Parameters:
        `state` - The new state for this component
      Throws:
        `LifecycleException` - when attempting to set an invalid state

    - #### setState

          protected void setState(LifecycleState state,
                                  Object data)
                           throws LifecycleException

      Provides a mechanism for sub-classes to update the component state. Calling this method will automatically fire any associated `Lifecycle` event. It will also check that any attempted state transition is valid for a sub-class.
      Parameters:
        `state` - The new state for this component
        `data` - The data to pass to the associated `Lifecycle` event
      Throws:
        `LifecycleException` - when attempting to set an invalid state

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