Class Lifecycle
- java.lang.Object
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- org.elasticsearch.common.component.Lifecycle
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public class Lifecycle extends java.lang.Object
Lifecycle state. Allows the following transitions:- INITIALIZED -> STARTED, STOPPED, CLOSED
- STARTED -> STOPPED
- STOPPED -> STARTED, CLOSED
- CLOSED ->
Also allows to stay in the same state. For example, when calling stop on a component, the following logic can be applied:
public void stop() { if (!lifecycleState.moveToStopped()) { return; } // continue with stop logic }
NOTE: The Lifecycle class is thread-safe. It is also possible to prevent concurrent state transitions by locking on the Lifecycle object itself. This is typically useful when chaining multiple transitions.
Note, closed is only allowed to be called when stopped, so make sure to stop the component first. Here is how the logic can be applied. A lock of the
lifecycleState
object is taken so that another thread cannot move the state fromSTOPPED
toSTARTED
before it has moved toCLOSED
.public void close() { synchronized (lifecycleState) { if (lifecycleState.started()) { stop(); } if (!lifecycleState.moveToClosed()) { return; } } // perform close logic here }
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Lifecycle.State
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Constructor Summary
Constructors Constructor Description Lifecycle()
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Method Summary
Modifier and Type Method Description boolean
canMoveToClosed()
boolean
canMoveToStarted()
boolean
canMoveToStopped()
boolean
closed()
Returnstrue
if the state is closed.boolean
initialized()
Returnstrue
if the state is initialized.boolean
moveToClosed()
boolean
moveToStarted()
boolean
moveToStopped()
boolean
started()
Returnstrue
if the state is started.Lifecycle.State
state()
boolean
stopped()
Returnstrue
if the state is stopped.boolean
stoppedOrClosed()
java.lang.String
toString()
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Method Detail
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state
public Lifecycle.State state()
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initialized
public boolean initialized()
Returnstrue
if the state is initialized.
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started
public boolean started()
Returnstrue
if the state is started.
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stopped
public boolean stopped()
Returnstrue
if the state is stopped.
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closed
public boolean closed()
Returnstrue
if the state is closed.
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stoppedOrClosed
public boolean stoppedOrClosed()
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canMoveToStarted
public boolean canMoveToStarted() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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moveToStarted
public boolean moveToStarted() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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canMoveToStopped
public boolean canMoveToStopped() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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moveToStopped
public boolean moveToStopped() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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canMoveToClosed
public boolean canMoveToClosed() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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moveToClosed
public boolean moveToClosed() throws java.lang.IllegalStateException
- Throws:
java.lang.IllegalStateException
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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