h1. Introduction

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Several concurrent life-cycles exist in Petals ESB:
* [the Petals ESB container life-cycle|#petals-esb-lifecycle],
* [the shared-library life-cycle|#sharedlibrary-lifecycle],
* [the component life-cycle|#component-lifecycle],
* [the service-assembly life-cycle|#service-assembly-lifecycle],
* [the service-unit life-cyle|#service-unit-lifecycle].

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{anchor:petals-esb-lifecycle}
h1. The Petals ESB container life-cyle

The Petals ESB container life-cycle is very simple.
{gliffy:name=Petals ESB lifecyle|version=2}
It contains only one state: STARTED. The implicit state 'STOPPED' does not really exist because in such state no Petals ESB process is running.

The transition from state 'STOPPED' to 'STARTED' is realized using the Petals ESB startup script '{{petals-esb}}'. The return to the state 'STOPPED' is realized using {{^C}} or the command '{{petals-esb stop}}'. See [Starting and stopping Petals ESB].

*When stopping a Petals ESB container, _all its components are shutdown_*. When starting the Petals ESB container, shared libraries, components, service assemblies and service units are restored to the state in which they was when stopping the container.

{anchor:sharedlibrary-lifecycle}
h1. The shared-library life-cyle

h2. The life-cycle

The shared-library life-cycle is simple.
{gliffy:name=Shared-Library lifecyle|version=3}
It contains only one state: INSTALLED. The implicit state 'UNINSTALLED' does not really exist because the shared-library is not instantiated or loaded.
The transition from state 'UNINSTALLED' to 'INSTALLED' is realized installing the shared library, and the return to the state 'UNINSTALLED' is realized uninstalling the shared-library. A shared library can be (un)installed using [Petals CLI|petalsesb:Command Line Interface], [the Petals Autoloader|Petals ESB "Autoloader"], Petals Ant Tasks or the JMX API.

{anchor:sharedlibrary-lifecycle-constraints}
h2. Constraints

The shared library life-cycle is linked to the component life-cycle:
* a shared library required by a component must be installed before to load the component
* a shared library can not be uninstalled until a component requiring it is installed.

|| Component state || installSharedLibrary || uninstallSharedLibrary ||
| UNLOADED | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! |
| LOADED/UNINSTALLED | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
| INSTALLED/SHUTDOWN | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
| STOPPED | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
| STARTED | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |

{anchor:component-lifecycle}
h1. The component life-cycle

h2. The life-cycle

The component life-cycle is the more complex life-cycle of Petals ESB life-cycles. It is composed of two correlated sub life-cycles:
* the component installer life-cycle that drives the installation of the component,
* the component life-cycle itself.

{gliffy:name=Component lifecyle|version=8}

The state {{INITIALIZED}} is a temporary state in the startup transition. The transition {{init}} and {{start}} are automatically enchained when starting a component from the state {{SHUTDOWN}}.

Actions associated to states:
* when initializing the component:
** the endpoints of the [native services|Glossary#Native_Service] are registered,
* when starting the component:
** it will be able to process request messages,
* when stopping the component, no more request message is processed,
** all resources (as database, pools, ...) used by the message processing are released,
* when shutting down the component:
** all resources (as database, pools, ...) used by the service unit (un)deployment on state {{STARTED}} and {{STOPPED}} are released,
** the endpoints of the native services are unregistered.

h2. Constraints

The component life-cycle is linked to:
* [the shared life-cycle|#sharedlibrary-lifecycle-constraints],
* [the service-assembly lifecycle|#serviceassembly-lifecycle-constraints],
* the service-unit life-cycle,
* and have following constraint against the service-unit life-cyle:
|| Service unit state || loadNewInstaller || install || start || stop || shutdown || uninstall || unloadInstaller ||
| UNDEPLOYED | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! |
| SHUTDOWN | !checkErro.png|align=center,width=20px!| !checkErro.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
| STOPPED | !checkErro.png|align=center,width=20px!| !checkErro.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
| STARTED | !checkErro.png|align=center,width=20px!| !checkErro.png|align=center,width=20px!| !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |
** component required by a service unit must be installed and running (ie. in state STOPPED or STARTED) before to deploy the service unit,
** if service units are deployed on, a component can only be started or stopped. All service units must be undeployed before to try any other transitions.
** stopping the container is the only way where the component is shutdown (without state persistence) even if service units are deployed on.

{anchor:service-assembly-lifecycle}
h1. The service-assembly life-cycle

h2. The life-cycle

The service assembly life-cycle can be viewed as a wrapper of its all service unit life-cycles. It propose to drive the life-cycle of its service-units in on operation.
{gliffy:name=Service-Assembly lifecyle}

The transitions from state 'UNDEPLOYED' to 'SHUTDOWN' is realized deploying the service assembly, and the return to the state 'UNDEPLOYED' is realized undeploying the service assembly. A service assembly can be (un)deployed/started/stopped/shutdown using [Petals CLI|petalsesb:Command Line Interface], [the Petals Autoloader|Petals ESB "Autoloader"], Petals Ant Tasks or the JMX API.

Actions associated to states:
* when deploying the service assembly, each service-unit not in state {{DEPLOYED}} is deployed,
* when starting the service assembly, each service-unit not in state {{STARTED}} is started,
* when stopping the service assembly, each service-unit not in state {{STOPPED}} is stopped,
* when shutting down the service assembly, each service-unit not in state {{SHUTDOWN}} is shutdown,
* when undeploying the service assembly, each service-unit not in state {{UNDEPLOYED}} is undeployed.

{anchor:serviceassembly-lifecycle-constraints}
h2. Constraints

The service assembly life-cycle is linked to the component life-cycle:
* to realize a transition on the service-assembly life-cycle, the component must be in state STARTED or STOPPED.

|| Component state || deploy || start || stop || shutdown || undeploy ||
| UNLOADED | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |!checkErro.png|align=center,width=20px! |
| LOADED/UNINSTALLED | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |!checkErro.png|align=center,width=20px! |
| INSTALLED/SHUTDOWN | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! | !checkErro.png|align=center,width=20px! |!checkErro.png|align=center,width=20px! |
| STOPPED | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! |!checkOk.png|align=center,width=20px! |
| STARTED | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! | !checkOk.png|align=center,width=20px! |!checkOk.png|align=center,width=20px! |

{anchor:service-unit-lifecycle}
h1. The service-unit life-cyle

Actions associated to states:
* when deploying a provider service unit, its endpoint is registered,
* when starting a service unit, consumption of services or external listening is started,
* when stopping a service unit, consumption of services or external listening is stopped,
* when undeploying a provider service unit, its endpoint is unregistered.