Lifecycle (server 7.2.1 API)

java.lang.Object
- org.elasticsearch.common.component.Lifecycle

```
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 from STOPPED to STARTED before it has moved to CLOSED.
```
 public void close() {
  synchronized (lifecycleState) {
      if (lifecycleState.started()) {
          stop();
      }
      if (!lifecycleState.moveToClosed()) {
          return;
      }
  }
  // perform close logic here
 }
 
```

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Lifecycle.State

Constructor Summary

Constructors
Constructor Description

Lifecycle()

Method Summary

Modifier and Type	Method	Description
`boolean`	`canMoveToClosed()`
`boolean`	`canMoveToStarted()`
`boolean`	`canMoveToStopped()`
`boolean`	`closed()`	Returns `true` if the state is closed.
`boolean`	`initialized()`	Returns `true` if the state is initialized.
`boolean`	`moveToClosed()`
`boolean`	`moveToStarted()`
`boolean`	`moveToStopped()`
`boolean`	`started()`	Returns `true` if the state is started.
`Lifecycle.State`	`state()`
`boolean`	`stopped()`	Returns `true` if the state is stopped.
`boolean`	`stoppedOrClosed()`
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail
- Lifecycle
```
public Lifecycle()
```

Method Detail

state
```
public Lifecycle.State state()
```

initialized
```
public boolean initialized()
```
Returns true if the state is initialized.

started
```
public boolean started()
```
Returns true if the state is started.

stopped
```
public boolean stopped()
```
Returns true if the state is stopped.

closed
```
public boolean closed()
```
Returns true if the state is closed.

stoppedOrClosed
```
public boolean stoppedOrClosed()
```

canMoveToStarted

public boolean canMoveToStarted()
                         throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

moveToStarted

public boolean moveToStarted()
                      throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

canMoveToStopped

public boolean canMoveToStopped()
                         throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

moveToStopped

public boolean moveToStopped()
                      throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

canMoveToClosed

public boolean canMoveToClosed()
                        throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

moveToClosed

public boolean moveToClosed()
                     throws java.lang.IllegalStateException

Throws:: java.lang.IllegalStateException

toString
```
public java.lang.String toString()
```
Overrides:

toString in class java.lang.Object