org.apache.hadoop.service

クラス ServiceStateModel

java.lang.Object

org.apache.hadoop.service.ServiceStateModel

@InterfaceAudience.Public
 @InterfaceStability.Evolving
public class ServiceStateModel
extends Object

Implements the service state model.

コンストラクタのサマリー

コンストラクタ

コンストラクタと説明
ServiceStateModel(String name) Create the service state model in the Service.STATE.NOTINITED state.
ServiceStateModel(String name, org.apache.hadoop.service.Service.STATE state) Create a service state model instance in the chosen state

メソッドのサマリー

修飾子とタイプ	メソッドと説明
static void	checkStateTransition(String name, org.apache.hadoop.service.Service.STATE state, org.apache.hadoop.service.Service.STATE proposed) Check that a state tansition is valid and throw an exception if not
void	ensureCurrentState(org.apache.hadoop.service.Service.STATE expectedState) Verify that that a service is in a given state.
org.apache.hadoop.service.Service.STATE	enterState(org.apache.hadoop.service.Service.STATE proposed) Enter a state -thread safe.
org.apache.hadoop.service.Service.STATE	getState() Query the service state.
boolean	isInState(org.apache.hadoop.service.Service.STATE proposed) Query that the state is in a specific state
static boolean	isValidStateTransition(org.apache.hadoop.service.Service.STATE current, org.apache.hadoop.service.Service.STATE proposed) Is a state transition valid?
String	toString() return the state text as the toString() value

クラスから継承されたメソッド java.lang.Object

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

コンストラクタの詳細

ServiceStateModel

public ServiceStateModel(String name)

Create the service state model in the Service.STATE.NOTINITED state.

ServiceStateModel

public ServiceStateModel(String name,
                         org.apache.hadoop.service.Service.STATE state)

Create a service state model instance in the chosen state

パラメータ:

state - the starting state

メソッドの詳細

getState

public org.apache.hadoop.service.Service.STATE getState()

Query the service state. This is a non-blocking operation.

戻り値:

the state

isInState

public boolean isInState(org.apache.hadoop.service.Service.STATE proposed)

Query that the state is in a specific state

パラメータ:

proposed - proposed new state

戻り値:

the state

ensureCurrentState

public void ensureCurrentState(org.apache.hadoop.service.Service.STATE expectedState)

Verify that that a service is in a given state.

パラメータ:

expectedState - the desired state

例外:

ServiceStateException - if the service state is different from the desired state

enterState

public org.apache.hadoop.service.Service.STATE enterState(org.apache.hadoop.service.Service.STATE proposed)

Enter a state -thread safe.

パラメータ:

proposed - proposed new state

戻り値:

the original state

例外:

ServiceStateException - if the transition is not permitted

checkStateTransition

public static void checkStateTransition(String name,
                                        org.apache.hadoop.service.Service.STATE state,
                                        org.apache.hadoop.service.Service.STATE proposed)

Check that a state tansition is valid and throw an exception if not

パラメータ:

name - name of the service (can be null)

state - current state

proposed - proposed new state

isValidStateTransition

public static boolean isValidStateTransition(org.apache.hadoop.service.Service.STATE current,
                                             org.apache.hadoop.service.Service.STATE proposed)

Is a state transition valid? There are no checks for current==proposed as that is considered a non-transition. using an array kills off all branch misprediction costs, at the expense of cache line misses.

パラメータ:

current - current state

proposed - proposed new state

戻り値:

true if the transition to a new state is valid

toString

public String toString()

return the state text as the toString() value

オーバーライド:

toString クラス内 Object

戻り値:

the current state's description