HeadTaskRunnable (OpenAM Project 15.1.7-SNAPSHOT API)

java.lang.Object
- com.sun.identity.common.HeadTaskRunnable

All Implemented Interfaces:

TaskRunnable, Runnable
```
public class HeadTaskRunnable
extends Object
implements TaskRunnable
```
HeadTaskRunnable is designed to be the head of the linked-list when TaskRunnable needs to be linked together. Whenever there is an insertion or deletion, HeadTaskRunnable must be locked to guarantee correct synchronization. Besides, when last element of the linked-list is removed (setNext(null)), HeadTaskRunnable should use Triggerable to remove or destroy the linked-list.

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`acquireCount`
`protected boolean`	`expired`
`protected TaskRunnable`	`nextTask`
`protected Thread`	`owner`
`protected Triggerable`	`parent`
`protected TaskRunnable`	`tailTask`
`protected Date`	`time`
`protected boolean`	`timeout`
`protected int`	`waitCount`

Constructor Summary

Constructors
Constructor and Description

HeadTaskRunnable(Triggerable parent, TaskRunnable nextTask, Date time)
Constructor of HeadTaskRunnable.

Constructors
Constructor and Description
`HeadTaskRunnable(Triggerable parent, TaskRunnable nextTask, Date time)` Constructor of HeadTaskRunnable.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`acquireValidLock()` Tries to acquire a valid (non-expired) lock.
`boolean`	`addElement(Object key)` Implements for TaskRunnable interface, always return false.
`void`	`cancel()` Implements for TaskRunnable interface.
`protected void`	`expire()` Sets the status of the HeadTask to expired.
`Thread`	`getCurrentOwner()` Returns the thread which currently holding this lock.
`HeadTaskRunnable`	`getHeadTask()` Implements for TaskRunnable interface, no actual use for HeadTaskRunnable.
`long`	`getRunPeriod()` Implements for TaskRunnable interface, HeadTaskRunnable doesn't have a run period.
`boolean`	`isEmpty()` Implements for TaskRunnable interface, always return false.
`boolean`	`isExpired()` Returns a boolean to indicate whether the HeadTask is expired already.
`boolean`	`isTimedOut()` Returns a boolean to indicate whether the HeadTask is timeout already.
`TaskRunnable`	`next()` Returns the TaskRunnable next to this TaskRunnable in the linked-list.
`TaskRunnable`	`previous()` Implements for TaskRunnable interface, there is no previous element for HeadTaskRunnable.
`void`	`releaseLockAndNotify()` Releases the currently holding lock.
`boolean`	`removeElement(Object key)` Implements for TaskRunnable interface, always return false.
`void`	`run()` Implements for TaskRunnable interface, just run the next TaskRunnable.
`long`	`scheduledExecutionTime()` Returns the time which this HeadTaskRunnable is scheduled.
`void`	`setHeadTask(HeadTaskRunnable headTask)` Implements for TaskRunnable interface, no actual use for HeadTaskRunnable.
`void`	`setNext(TaskRunnable task)` Sets the TaskRunnable next to this TaskRunnable in the linked-list.
`void`	`setPrevious(TaskRunnable task)` Implements for TaskRunnable interface, There is no previous element for HeadTaskRunnable.
`void`	`setTail(TaskRunnable task)` Sets the task which is the tail of the list.
`void`	`setTrigger(Triggerable parent)` Sets the Triggerable interface which will be run when the linked-list is empty.
`TaskRunnable`	`tail()` Returns the Task which is at the tail of the list.
`protected void`	`timeout()` Sets the status of the HeadTask to timeout.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - time
```
protected Date time
```
  - nextTask
```
protected volatile TaskRunnable nextTask
```
  - tailTask
```
protected volatile TaskRunnable tailTask
```
  - expired
```
protected volatile boolean expired
```
  - timeout
```
protected volatile boolean timeout
```
  - waitCount
```
protected int waitCount
```
  - acquireCount
```
protected int acquireCount
```
  - owner
```
protected volatile Thread owner
```
  - parent
```
protected Triggerable parent
```
- Constructor Detail
  - HeadTaskRunnable
```
public HeadTaskRunnable(Triggerable parent,
                        TaskRunnable nextTask,
                        Date time)
                 throws IllegalArgumentException
```
    Constructor of HeadTaskRunnable.
    
    Parameters:
    
    parent - The Triggerable interface to be run when the linked-list is empty
    
    nextTask - The TaskRunnable next to this TaskRunnable
    
    time - The time this TaskRunnable is scheduled
    
    Throws:
    
    IllegalArgumentException
- Method Detail
  - expire
```
protected void expire()
               throws IllegalMonitorStateException
```
    Sets the status of the HeadTask to expired.
    
    Throws:
    
    IllegalMonitorStateException
  - timeout
```
protected void timeout()
                throws IllegalMonitorStateException
```
    Sets the status of the HeadTask to timeout.
    
    Throws:
    
    IllegalMonitorStateException
  - isTimedOut
```
public boolean isTimedOut()
```
    Returns a boolean to indicate whether the HeadTask is timeout already.
    
    Returns:
    
    a boolen to indicate whether the HeadTask is timeout.
  - isExpired
```
public boolean isExpired()
```
    Returns a boolean to indicate whether the HeadTask is expired already.
    
    Returns:
    
    a boolean to indicate whether the HeadTask is expired.
  - getCurrentOwner
```
public Thread getCurrentOwner()
```
    Returns the thread which currently holding this lock.
    
    Returns:
    
    the thread which currently own the lock or null.
  - acquireValidLock
```
public boolean acquireValidLock()
```
    Tries to acquire a valid (non-expired) lock.
    
    Returns:
    
    a boolean to indicate whether it is succeed to acquire the lock.
  - releaseLockAndNotify
```
public void releaseLockAndNotify()
                          throws IllegalMonitorStateException
```
    Releases the currently holding lock.
    
    Throws:
    
    IllegalMonitorStateException
  - setHeadTask
```
public void setHeadTask(HeadTaskRunnable headTask)
```
    Implements for TaskRunnable interface, no actual use for HeadTaskRunnable.
    
    Specified by:
    
    setHeadTask in interface TaskRunnable
    
    Parameters:
    
    headTask - The HeadTaskRunnable
  - getHeadTask
```
public HeadTaskRunnable getHeadTask()
```
    Implements for TaskRunnable interface, no actual use for HeadTaskRunnable.
    
    Specified by:
    
    getHeadTask in interface TaskRunnable
    
    Returns:
    
    The head task of this linkable TaskRunnable
  - addElement
```
public boolean addElement(Object key)
```
    Implements for TaskRunnable interface, always return false.
    
    Specified by:
    
    addElement in interface TaskRunnable
    
    Parameters:
    
    key - Element to be added to this TaskRunnable
    
    Returns:
    
    false means nothing can be added to this TaskRunnable
  - removeElement
```
public boolean removeElement(Object key)
```
    Implements for TaskRunnable interface, always return false.
    
    Specified by:
    
    removeElement in interface TaskRunnable
    
    Parameters:
    
    key - Element to be removed from this TaskRunnable
    
    Returns:
    
    false means nothing can be removed from this TaskRunnable
  - isEmpty
```
public boolean isEmpty()
```
    Implements for TaskRunnable interface, always return false.
    
    Specified by:
    
    isEmpty in interface TaskRunnable
    
    Returns:
    
    true means this TaskRunnable is always empty
  - setNext
```
public void setNext(TaskRunnable task)
```
    Sets the TaskRunnable next to this TaskRunnable in the linked-list.
    
    Specified by:
    
    setNext in interface TaskRunnable
    
    Parameters:
    
    task - The next TaskRunnable
  - setPrevious
```
public void setPrevious(TaskRunnable task)
```
    Implements for TaskRunnable interface, There is no previous element for HeadTaskRunnable.
    
    Specified by:
    
    setPrevious in interface TaskRunnable
    
    Parameters:
    
    task - The previous TaskRunnable
  - next
```
public TaskRunnable next()
```
    Returns the TaskRunnable next to this TaskRunnable in the linked-list.
    
    Specified by:
    
    next in interface TaskRunnable
    
    Returns:
    
    next TaskRunnable object or null if it is not set
  - previous
```
public TaskRunnable previous()
```
    Implements for TaskRunnable interface, there is no previous element for HeadTaskRunnable.
    
    Specified by:
    
    previous in interface TaskRunnable
    
    Returns:
    
    null means there is no previous element
  - getRunPeriod
```
public long getRunPeriod()
```
    Implements for TaskRunnable interface, HeadTaskRunnable doesn't have a run period.
    
    Specified by:
    
    getRunPeriod in interface TaskRunnable
    
    Returns:
    
    -1 means the task only will be run once
  - cancel
```
public void cancel()
```
    Implements for TaskRunnable interface.
    
    Specified by:
    
    cancel in interface TaskRunnable
  - setTrigger
```
public void setTrigger(Triggerable parent)
```
    Sets the Triggerable interface which will be run when the linked-list is empty.
    
    Parameters:
    
    parent - The Triggerable interface to be run when the linked-list is empty
  - setTail
```
public void setTail(TaskRunnable task)
```
    Sets the task which is the tail of the list. It is for internal use only.
    
    Parameters:
    
    task - The task which is at the tail of the list.
  - tail
```
public TaskRunnable tail()
```
    Returns the Task which is at the tail of the list.
    
    Returns:
    
    The task which is at the tail of the list.
  - scheduledExecutionTime
```
public long scheduledExecutionTime()
```
    Returns the time which this HeadTaskRunnable is scheduled.
    
    Specified by:
    
    scheduledExecutionTime in interface TaskRunnable
    
    Returns:
    
    The long value which represents the time this task is scheduled
  - run
```
public void run()
```
    Implements for TaskRunnable interface, just run the next TaskRunnable.
    
    Specified by:
    
    run in interface Runnable

Class HeadTaskRunnable

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

time

nextTask

tailTask

expired

timeout

waitCount

acquireCount

owner

parent

Constructor Detail

HeadTaskRunnable

Method Detail

expire

timeout

isTimedOut

isExpired

getCurrentOwner

acquireValidLock

releaseLockAndNotify

setHeadTask

getHeadTask

addElement

removeElement

isEmpty

setNext

setPrevious

next

previous

getRunPeriod

cancel

setTrigger

setTail

tail

scheduledExecutionTime

run