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java.lang.Object org.apache.hadoop.service.AbstractService org.apache.hadoop.service.CompositeService
@InterfaceAudience.Public @InterfaceStability.Evolving public class CompositeService
Composition of services.
Field Summary | |
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protected static boolean |
STOP_ONLY_STARTED_SERVICES
Policy on shutdown: attempt to close everything (purest) or only try to close started services (which assumes that the service implementations may not handle the stop() operation except when started. |
Constructor Summary | |
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CompositeService(String name)
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Method Summary | |
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protected boolean |
addIfService(Object object)
If the passed object is an instance of Service ,
add it to the list of services managed by this CompositeService |
protected void |
addService(Service service)
Add the passed Service to the list of services managed by this
CompositeService |
List<Service> |
getServices()
Get a cloned list of services |
protected boolean |
removeService(Service service)
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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. |
Methods inherited from class org.apache.hadoop.service.AbstractService |
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close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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protected static final boolean STOP_ONLY_STARTED_SERVICES
Constructor Detail |
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public CompositeService(String name)
Method Detail |
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public List<Service> getServices()
protected void addService(Service service)
Service
to the list of services managed by this
CompositeService
service
- the Service
to be addedprotected boolean addIfService(Object object)
Service
,
add it to the list of services managed by this CompositeService
object
-
protected boolean removeService(Service service)
protected void serviceInit(Configuration conf) throws Exception
AbstractService
AbstractService.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
serviceInit
in class AbstractService
conf
- configuration
Exception
- on a failure -these will be caught,
possibly wrapped, and wil; trigger a service stopprotected void serviceStart() throws Exception
AbstractService
AbstractService.start()
prevents re-entrancy.
serviceStart
in class AbstractService
Exception
- if needed -these will be caught,
wrapped, and trigger a service stopprotected void serviceStop() throws Exception
AbstractService
AbstractService.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.
serviceStop
in class AbstractService
Exception
- if needed -these will be caught and logged.
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