AbstractService (Apache Hadoop Main 3.0.0-alpha2-SNAPSHOT API)

java.lang.Object
- org.apache.hadoop.service.AbstractService

すべての実装されたインタフェース:

Closeable, AutoCloseable, Service

直系の既知のサブクラス:

AbstractLivelinessMonitor, AHSClient, AMRMClient, AMRMClientAsync, AsyncDispatcher, CompositeService, HistoryFileManager, NMClient, NMClientAsync, SharedCacheClient, TimelineClient, YarnClient
```
@InterfaceAudience.Public
 @InterfaceStability.Evolving
public abstract class AbstractService
extends Object
implements Service
```
This is the base implementation class for services.

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

AbstractService(String name)
Construct the service.

コンストラクタ
コンストラクタと説明
`AbstractService(String name)` Construct the service.

メソッドのサマリー

すべてのメソッド staticメソッドインスタンス・メソッド concreteメソッド
修飾子とタイプ	メソッドと説明
`void`	`close()` Relay to `stop()`
`Map<String,String>`	`getBlockers()` Get the blockers on a service -remote dependencies that are stopping the service from being live.
`Configuration`	`getConfig()` Get the configuration of this service.
`Throwable`	`getFailureCause()` Get the first exception raised during the service failure.
`org.apache.hadoop.service.Service.STATE`	`getFailureState()` Get the state in which the failure in `Service.getFailureCause()` occurred.
`List<LifecycleEvent>`	`getLifecycleHistory()` Get a snapshot of the lifecycle history; it is a static list
`String`	`getName()` Get the name of this service.
`org.apache.hadoop.service.Service.STATE`	`getServiceState()` Get the current service state
`long`	`getStartTime()` Get the service start time
`void`	`init(Configuration conf)` Initialize the service.
`boolean`	`isInState(org.apache.hadoop.service.Service.STATE expected)` Query to see if the service is in a specific state.
`protected void`	`noteFailure(Exception exception)` Failure handling: record the exception that triggered it -if there was not one already.
`protected void`	`putBlocker(String name, String details)` Put a blocker to the blocker map -replacing any with the same name.
`static void`	`registerGlobalListener(ServiceStateChangeListener l)` Register a global listener, which receives notifications from the state change events of all services in the JVM
`void`	`registerServiceListener(ServiceStateChangeListener l)` Register a listener to the service state change events.
`void`	`removeBlocker(String name)` Remove a blocker from the blocker map - this is a no-op if the blocker is not present
`protected void`	`serviceInit(Configuration conf)` All initialization code needed by a service.
`protected void`	`serviceStart()` Actions called during the INITED to STARTED transition.
`protected void`	`serviceStop()` Actions called during the transition to the STOPPED state.
`protected void`	`setConfig(Configuration conf)` Set the configuration for this service.
`void`	`start()` Start the service.
`void`	`stop()` Stop the service.
`String`	`toString()`
`static boolean`	`unregisterGlobalListener(ServiceStateChangeListener l)` unregister a global listener.
`void`	`unregisterServiceListener(ServiceStateChangeListener l)` Unregister a previously registered listener of the service state change events.
`boolean`	`waitForServiceToStop(long timeout)` Block waiting for the service to stop; uses the termination notification object to do so.

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
  - AbstractService
```
public AbstractService(String name)
```
    Construct the service.
    
    パラメータ:
    
    name - service name
- メソッドの詳細
  - getServiceState
```
public final org.apache.hadoop.service.Service.STATE getServiceState()
```
    インタフェースからコピーされた説明: Service
    
    Get the current service state
    
    定義:
    
    getServiceState インタフェース内 Service
    
    戻り値:
    
    the state of the service
  - getFailureCause
```
public final Throwable getFailureCause()
```
    インタフェースからコピーされた説明: Service
    
    Get the first exception raised during the service failure. If null, no exception was logged
    
    定義:
    
    getFailureCause インタフェース内 Service
    
    戻り値:
    
    the failure logged during a transition to the stopped state
  - getFailureState
```
public org.apache.hadoop.service.Service.STATE getFailureState()
```
    インタフェースからコピーされた説明: Service
    
    Get the state in which the failure in Service.getFailureCause() occurred.
    
    定義:
    
    getFailureState インタフェース内 Service
    
    戻り値:
    
    the state or null if there was no failure
  - setConfig
```
protected void setConfig(Configuration conf)
```
    Set the configuration for this service. This method is called during init(Configuration) and should only be needed if for some reason a service implementation needs to override that initial setting -for example replacing it with a new subclass of Configuration
    
    パラメータ:
    
    conf - new configuration.
  - init
```
public void init(Configuration conf)
```
    Initialize the service. The transition MUST be from Service.STATE.NOTINITED to Service.STATE.INITED unless the operation failed and an exception was raised, in which case Service.stop() MUST be invoked and the service enter the state Service.STATE.STOPPED. This invokes serviceInit(org.apache.hadoop.conf.Configuration)
    
    定義:
    
    init インタフェース内 Service
    
    パラメータ:
    
    conf - the configuration of the service. This must not be null
    
    例外:
    
    ServiceStateException - if the configuration was null, the state change not permitted, or something else went wrong
  - start
```
public void start()
```
    Start the service. The transition MUST be from Service.STATE.INITED to Service.STATE.STARTED unless the operation failed and an exception was raised, in which case Service.stop() MUST be invoked and the service enter the state Service.STATE.STOPPED.
    
    定義:
    
    start インタフェース内 Service
    
    例外:
    
    ServiceStateException - if the current service state does not permit this action
  - stop
```
public void stop()
```
    Stop the service. This MUST be a no-op if the service is already in the Service.STATE.STOPPED state. It SHOULD be a best-effort attempt to stop all parts of the service. The implementation must be designed to complete regardless of the service state, including the initialized/uninitialized state of all its internal fields.
    
    定義:
    
    stop インタフェース内 Service
  - close
```
public final void close()
                 throws IOException
```
    Relay to stop()
    
    定義:
    
    close インタフェース内 Closeable
    
    定義:
    
    close インタフェース内 AutoCloseable
    
    定義:
    
    close インタフェース内 Service
    
    例外:
    
    IOException
  - noteFailure
```
protected final void noteFailure(Exception exception)
```
    Failure handling: record the exception that triggered it -if there was not one already. Services are free to call this themselves.
    
    パラメータ:
    
    exception - the exception
  - waitForServiceToStop
```
public final boolean waitForServiceToStop(long timeout)
```
    インタフェースからコピーされた説明: Service
    
    Block waiting for the service to stop; uses the termination notification object to do so. This method will only return after all the service stop actions have been executed (to success or failure), or the timeout elapsed This method can be called before the service is inited or started; this is to eliminate any race condition with the service stopping before this event occurs.
    
    定義:
    
    waitForServiceToStop インタフェース内 Service
    
    パラメータ:
    
    timeout - timeout in milliseconds. A value of zero means "forever"
    
    戻り値:
    
    true iff the service stopped in the time period
  - serviceInit
```
protected void serviceInit(Configuration conf)
                    throws Exception
```
    All initialization code needed by a service. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in init(Configuration) prevents re-entrancy. The base implementation checks to see if the subclass has created a new configuration instance, and if so, updates the base class value
    
    パラメータ:
    
    conf - configuration
    
    例外:
    
    Exception - on a failure -these will be caught, possibly wrapped, and wil; trigger a service stop
  - serviceStart
```
protected void serviceStart()
                     throws Exception
```
    Actions called during the INITED to STARTED transition. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in start() prevents re-entrancy.
    
    例外:
    
    Exception - if needed -these will be caught, wrapped, and trigger a service stop
  - serviceStop
```
protected void serviceStop()
                    throws Exception
```
    Actions called during the transition to the STOPPED state. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in stop() prevents re-entrancy. Implementations MUST write this to be robust against failures, including checks for null references -and for the first failure to not stop other attempts to shut down parts of the service.
    
    例外:
    
    Exception - if needed -these will be caught and logged.
  - registerServiceListener
```
public void registerServiceListener(ServiceStateChangeListener l)
```
    インタフェースからコピーされた説明: Service
    
    Register a listener to the service state change events. If the supplied listener is already listening to this service, this method is a no-op.
    
    定義:
    
    registerServiceListener インタフェース内 Service
    
    パラメータ:
    
    l - a new listener
  - unregisterServiceListener
```
public void unregisterServiceListener(ServiceStateChangeListener l)
```
    インタフェースからコピーされた説明: Service
    
    Unregister a previously registered listener of the service state change events. No-op if the listener is already unregistered.
    
    定義:
    
    unregisterServiceListener インタフェース内 Service
    
    パラメータ:
    
    l - the listener to unregister.
  - registerGlobalListener
```
public static void registerGlobalListener(ServiceStateChangeListener l)
```
    Register a global listener, which receives notifications from the state change events of all services in the JVM
    
    パラメータ:
    
    l - listener
  - unregisterGlobalListener
```
public static boolean unregisterGlobalListener(ServiceStateChangeListener l)
```
    unregister a global listener.
    
    パラメータ:
    
    l - listener to unregister
    
    戻り値:
    
    true if the listener was found (and then deleted)
  - getName
```
public String getName()
```
    インタフェースからコピーされた説明: Service
    
    Get the name of this service.
    
    定義:
    
    getName インタフェース内 Service
    
    戻り値:
    
    the service name
  - getConfig
```
public Configuration getConfig()
```
    インタフェースからコピーされた説明: Service
    
    Get the configuration of this service. This is normally not a clone and may be manipulated, though there are no guarantees as to what the consequences of such actions may be
    
    定義:
    
    getConfig インタフェース内 Service
    
    戻り値:
    
    the current configuration, unless a specific implentation chooses otherwise.
  - getStartTime
```
public long getStartTime()
```
    インタフェースからコピーされた説明: Service
    
    Get the service start time
    
    定義:
    
    getStartTime インタフェース内 Service
    
    戻り値:
    
    the start time of the service. This will be zero if the service has not yet been started.
  - getLifecycleHistory
```
public List<LifecycleEvent> getLifecycleHistory()
```
    インタフェースからコピーされた説明: Service
    
    Get a snapshot of the lifecycle history; it is a static list
    
    定義:
    
    getLifecycleHistory インタフェース内 Service
    
    戻り値:
    
    a possibly empty but never null list of lifecycle events.
  - isInState
```
public final boolean isInState(org.apache.hadoop.service.Service.STATE expected)
```
    インタフェースからコピーされた説明: Service
    
    Query to see if the service is in a specific state. In a multi-threaded system, the state may not hold for very long.
    
    定義:
    
    isInState インタフェース内 Service
    
    パラメータ:
    
    expected - the expected state
    
    戻り値:
    
    true if, at the time of invocation, the service was in that state.
  - toString
```
public String toString()
```
    オーバーライド:
    
    toString クラス内 Object
  - putBlocker
```
protected void putBlocker(String name,
                          String details)
```
    Put a blocker to the blocker map -replacing any with the same name.
    
    パラメータ:
    
    name - blocker name
    
    details - any specifics on the block. This must be non-null.
  - removeBlocker
```
public void removeBlocker(String name)
```
    Remove a blocker from the blocker map - this is a no-op if the blocker is not present
    
    パラメータ:
    
    name - the name of the blocker
  - getBlockers
```
public Map<String,String> getBlockers()
```
    インタフェースからコピーされた説明: Service
    
    Get the blockers on a service -remote dependencies that are stopping the service from being live.
    
    定義:
    
    getBlockers インタフェース内 Service
    
    戻り値:
    
    a (snapshotted) map of blocker name->description values

クラス AbstractService

コンストラクタのサマリー

メソッドのサマリー

クラスから継承されたメソッド java.lang.Object

コンストラクタの詳細

AbstractService

メソッドの詳細

getServiceState

getFailureCause

getFailureState

setConfig

init

start

stop

close

noteFailure

waitForServiceToStop

serviceInit

serviceStart

serviceStop

registerServiceListener

unregisterServiceListener

registerGlobalListener

unregisterGlobalListener

getName

getConfig

getStartTime

getLifecycleHistory

isInState

toString

putBlocker

removeBlocker

getBlockers