com.fredhopper.lifecycle

Class AbstractLifeCycle

java.lang.Object

com.fredhopper.lifecycle.AbstractLifeCycle

All Implemented Interfaces:

LifeCycle, Resumable, Stateful, Supplier<State>

Direct Known Subclasses:

Container

public abstract class AbstractLifeCycle
extends Object
implements LifeCycle

A base implementation structure for LifeCycle.

Constructor Summary

Constructors

Constructor and Description
AbstractLifeCycle()

Method Summary

Modifier and Type	Method and Description
void	addStateListener(StateListener listener) Add a new StateListener
protected void	changeState(State from, State to) First changes the state from a current value to a target value.
protected abstract void	doInitLifeCycle() Similar to initLifeCycle() for inherited classes.
protected void	doPause() Similar to pause() for inherited classes.
protected void	doResume() Similar to resume() for inherited classes.
protected abstract void	doStartLifeCycle() Similar to startLifeCycle() for inherited classes.
protected abstract void	doStopLifeCycle() Similar to stopLifeCycle() for inherited classes.
State	getState()
Collection<StateListener>	getStateListeners()
void	initLifeCycle() Initializes the life cycle before invoking LifeCycle.startLifeCycle().
void	pause() Makes an attempt to pause the resumable.
protected void	publishState(State from, State to) Propagates a change of State to all the StateListenerregistered with this life cycle object.
void	removeStateListener(StateListener listener) Remove a registered StateListener
void	resume() Makes an attempt to resume a paused resumable.
void	startLifeCycle() Starts the life cycle.
void	stopLifeCycle() Stops the life cycle.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.fredhopper.lifecycle.Stateful

get

Constructor Detail

AbstractLifeCycle

public AbstractLifeCycle()

Method Detail

getState

public State getState()

Specified by:

getState in interface Stateful

Returns:

the current state

getStateListeners

public Collection<StateListener> getStateListeners()

Specified by:

getStateListeners in interface Stateful

Returns:

the collection of StateListener for this.

initLifeCycle

public void initLifeCycle()
                   throws Exception

Description copied from interface: LifeCycle

Initializes the life cycle before invoking LifeCycle.startLifeCycle(). It is expected that Stateful.getState() should be State.INITIALIZED after completion of this method.

Specified by:

initLifeCycle in interface LifeCycle

Throws:

Exception - expected to be thrown if the initialization cannot be complete.

startLifeCycle

public void startLifeCycle()
                    throws Exception

Description copied from interface: LifeCycle

Starts the life cycle. It is expected that Stateful.getState() should be State.STARTING while the method is not finished and State.RUNNING on successful completion.

Specified by:

startLifeCycle in interface LifeCycle

Throws:

Exception - should be thrown if the starting of the life cycle object cannot complete.

pause

public void pause()
           throws Exception

Description copied from interface: Resumable

Makes an attempt to pause the resumable.

Specified by:

pause in interface Resumable

Throws:

Exception - if the resumable cannot be paused and an exception is necessary.

resume

public void resume()
            throws Exception

Description copied from interface: Resumable

Makes an attempt to resume a paused resumable.

Specified by:

resume in interface Resumable

Throws:

Exception - if the resumable cannot be resumed. The exception could be also because of invalid states.

stopLifeCycle

public void stopLifeCycle()
                   throws Exception

Description copied from interface: LifeCycle

Stops the life cycle. It is expected that Stateful.getState() should be State.STOPPING while the method is not finished and State.STOPPED on successful completion.

Specified by:

stopLifeCycle in interface LifeCycle

Throws:

Exception - should be thrown if the stopping fails. It is recommended to perform clean-up guidelines. In addition, it is recommended to still fail in a state such that killing JVM process does not have a corruptive effect on the state.

addStateListener

public void addStateListener(StateListener listener)

Add a new StateListener

Parameters:

listener - the StateListener to add

removeStateListener

public void removeStateListener(StateListener listener)

Remove a registered StateListener

Parameters:

listener - the StateListener to remove

toString

public String toString()

Overrides:

toString in class Object

changeState

protected void changeState(State from,
                           State to)
                    throws Exception

First changes the state from a current value to a target value. Second, publishes the change of state to all the listeners through getStateListeners().

Parameters:

from - the current state

to - the new state

Throws:

Exception - if the state cannot be changed or some StateListenerfailed to apply the same change.

publishState

protected void publishState(State from,
                            State to)
                     throws Exception

Propagates a change of State to all the StateListenerregistered with this life cycle object.

Parameters:

from - the old state

to - the new state

Throws:

Exception - if a listener fails to accept the change

See Also:

changeState(State, State)

doInitLifeCycle

protected abstract void doInitLifeCycle()
                                 throws Exception

Similar to initLifeCycle() for inherited classes.

Throws:

Exception - See initLifeCycle()

See Also:

LifeCycle.initLifeCycle()

doStartLifeCycle

protected abstract void doStartLifeCycle()
                                  throws Exception

Similar to startLifeCycle() for inherited classes.

Throws:

Exception - See startLifeCycle()

See Also:

LifeCycle.startLifeCycle()

doPause

protected void doPause()
                throws Exception

Similar to pause() for inherited classes.

Throws:

Exception - See pause()

See Also:

Resumable.pause()

doResume

protected void doResume()
                 throws Exception

Similar to resume() for inherited classes.

Throws:

Exception - See resume()

See Also:

Resumable.resume()

doStopLifeCycle

protected abstract void doStopLifeCycle()
                                 throws Exception

Similar to stopLifeCycle() for inherited classes.

Throws:

Exception - See stopLifeCycle()

See Also:

LifeCycle.stopLifeCycle()