DoubleLaunchChecker (Jenkins core 2.454 API)

java.lang.Object
- hudson.model.AbstractModelObject
- - hudson.model.AdministrativeMonitor
  - - hudson.util.DoubleLaunchChecker

All Implemented Interfaces:

ExtensionPoint, ModelObject, SearchableModelObject, SearchItem, org.kohsuke.stapler.StaplerProxy
```
@Extension
public class DoubleLaunchChecker
extends AdministrativeMonitor
```
Makes sure that no other Hudson uses our JENKINS_HOME directory, to forestall the problem of running multiple instances of Hudson that point to the same data directory.
This set up error occasionally happens especially when the user is trying to reassign the context path of the app, and it results in a hard-to-diagnose error, so we actively check this.
The mechanism is simple. This class occasionally updates a known file inside the hudson home directory, and whenever it does so, it monitors the timestamp of the file to make sure no one else is updating this file. In this way, while we cannot detect the problem right away, within a reasonable time frame we can detect the collision.

Since:

1.178

Author:

Kohsuke Kawaguchi

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class DoubleLaunchChecker.Schedule
- Nested classes/interfaces inherited from interface hudson.ExtensionPoint
  ExtensionPoint.LegacyInstancesAreScopedToHudson

Field Summary

Fields
Modifier and Type Field Description

File home
- Fields inherited from class hudson.model.AdministrativeMonitor
  id

Constructor Summary

Constructors
Constructor Description

DoubleLaunchChecker()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`execute()`
`String`	`getCollidingId()`
`String`	`getDisplayName()`
`String`	`getId()`	Figures out a string that identifies this instance of Hudson.
`boolean`	`isActivated()`	Returns true if this monitor is activated and wants to produce a warning message.

Methods inherited from class hudson.model.AdministrativeMonitor
all, disable, doDisable, getRequiredPermission, getSearchUrl, getTarget, getUrl, isEnabled, isSecurity

Methods inherited from class hudson.model.AbstractModelObject
getSearch, getSearchIndex, getSearchName, makeSearchIndex, requirePOST, sendError, sendError, sendError, sendError, sendError

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

- Field Detail
  - home
```
public final File home
```
- Constructor Detail
  - DoubleLaunchChecker
```
public DoubleLaunchChecker()
```
- Method Detail
  - getDisplayName
```
public String getDisplayName()
```
    Specified by:
    
    getDisplayName in interface ModelObject
    
    Overrides:
    
    getDisplayName in class AdministrativeMonitor
  - isActivated
```
public boolean isActivated()
```
    Description copied from class: AdministrativeMonitor
    
    Returns true if this monitor is activated and wants to produce a warning message.
    This method is called from the HTML rendering thread, so it should run efficiently.
    
    Specified by:
    
    isActivated in class AdministrativeMonitor
  - execute
```
protected void execute()
```
  - getId
```
public String getId()
```
    Figures out a string that identifies this instance of Hudson.
  - getCollidingId
```
public String getCollidingId()
```