java.lang.Object
- org.restlet.Restlet
- - org.restlet.Component

All Implemented Interfaces:

Uniform
```
public class Component
extends Restlet
```
Restlet managing a set of Connectors, VirtualHosts, Services and Applications. Applications are expected to be directly attached to virtual hosts or to the internal router (see RIAP pseudo-protocol for usage). Components also expose several services: access logging and status setting.

From an architectural point of view, here is the REST definition: "A component is an abstract unit of software instructions and internal state that provides a transformation of data via its interface." Roy T. Fielding

The configuration of a Component can be done programmatically or by using a XML document. There are dedicated constructors that accept either an URI reference to such XML document or a representation of such XML document, allowing easy configuration of the list of supported client and server connectors as well as services. In addition, you can add and configure virtual hosts (including the default one). Finally, you can attach applications either using their fully qualified class name or by pointing to a descriptor document (at this time only WADL description are supported, see the WADL Restlet extension for details).

The XML Schema of the configuration files is available both online and inside the API JAR under the "org.restlet.Component.xsd" name. Here is a sample of XML configuration:
```
 <?xml version="1.0"?>
 <component xmlns="http://restlet.org/schemas/2.0/Component">
    <client protocol="CLAP" />
    <client protocol="FILE" />
    <client protocols="HTTP HTTPS" />
    <server protocols="HTTP HTTPS" />
 
    <defaultHost>
       <attach uriPattern="/abcd/{xyz}" 
                  targetClass="org.restlet.test.MyApplication" />
       <attach uriPattern="/efgh/{xyz}"
                  targetDescriptor="clap://class/org/restlet/test/MyApplication.wadl" />
    </defaultHost>
 </component>
 
```
Components also have useful services associated. They are all enabled by default and are available as properties that can be eventually overridden:
- "logService" to configure access logging.
- "statusService" to provide common representations for exception status.
- "taskService" to run tasks asynchronously.
Concurrency note: instances of this class or its subclasses can be invoked by several threads at the same time and therefore must be thread-safe. You should be especially careful when storing state in member variables.
Author:

Jerome Louvel

See Also:

Source dissertation

Constructor Summary

Constructors
Constructor	Description
`Component()`	Constructor.
`Component(java.lang.String xmlConfigurationRef)`	Deprecated. Use XML support in the Spring extension instead.
`Component(Reference xmlConfigRef)`	Deprecated. Use XML support in the Spring extension instead.
`Component(Representation xmlConfigRepresentation)`	Deprecated. Use XML support in the Spring extension instead.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`ClientList`	`getClients()`	Returns a modifiable list of client connectors.
`VirtualHost`	`getDefaultHost()`	Returns the default virtual host.
`java.util.List<VirtualHost>`	`getHosts()`	Returns the modifiable list of virtual hosts.
`Router`	`getInternalRouter()`	Returns the private internal router where Restlets like Applications can be attached.
`LogService`	`getLogService()`	Returns the global log service.
`Realm`	`getRealm(java.lang.String name)`	Finds the realm with the given name.
`java.util.List<Realm>`	`getRealms()`	Returns the modifiable list of security realms.
`ServerList`	`getServers()`	Returns the modifiable list of server connectors.
`ServiceList`	`getServices()`	Returns the modifiable list of services.
`StatusService`	`getStatusService()`	Deprecated. Use `Application.getStatusService()` instead.
`TaskService`	`getTaskService()`	Returns a task service to run concurrent tasks.
`void`	`handle(Request request, Response response)`	Handles a call.
`static void`	`main(java.lang.String[] args)`	Deprecated. Use XML support in the Spring extension instead.
`void`	`setClients(ClientList clients)`	Sets the modifiable list of client connectors.
`void`	`setContext(Context context)`	Sets the context.
`void`	`setDefaultHost(VirtualHost defaultHost)`	Sets the default virtual host.
`void`	`setHosts(java.util.List<VirtualHost> hosts)`	Sets the modifiable list of virtual hosts.
`void`	`setInternalRouter(Router internalRouter)`	Sets the private internal router were Restlets like Applications can be attached.
`void`	`setLogService(LogService logService)`	Sets the global log service.
`void`	`setRealms(java.util.List<Realm> realms)`	Sets the list of realms.
`void`	`setServers(ServerList servers)`	Sets the modifiable list of server connectors.
`void`	`setStatusService(StatusService statusService)`	Deprecated. Use `Application.setStatusService(StatusService)` instead.
`void`	`setTaskService(TaskService taskService)`	Sets the task service.
`void`	`start()`	Starts the component.
`protected void`	`startClients()`	Starts the client connectors.
`protected void`	`startHelper()`	Starts the internal helper allowing incoming requests to be served.
`protected void`	`startRealms()`	Starts the realms.
`protected void`	`startRouters()`	Starts the virtual hosts and the internal router.
`protected void`	`startServers()`	Starts the server connectors.
`protected void`	`startServices()`	Starts the associated services.
`void`	`stop()`	Stops the component.
`protected void`	`stopClients()`	Stops the client connectors.
`protected void`	`stopHelper()`	Stops the internal helper allowing incoming requests to be served.
`protected void`	`stopRealms()`	Stops the realms.
`protected void`	`stopRouters()`	Stops the virtual hosts and the internal router.
`protected void`	`stopServers()`	Stops the server connectors.
`protected void`	`stopServices()`	Stops the associated services.
`void`	`updateHosts()`	Updates the component to take into account changes to the virtual hosts.

Methods inherited from class org.restlet.Restlet
createFinder, finalize, getApplication, getAuthor, getContext, getDescription, getFinderClass, getLogger, getName, getOwner, handle, handle, handle, isStarted, isStopped, setAuthor, setDescription, setFinderClass, setName, setOwner

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

- Constructor Detail
  - Component
```
public Component()
```
    Constructor.
  - Component
```
@Deprecated
public Component(Reference xmlConfigRef)
```
    Deprecated.
    Use XML support in the Spring extension instead.
    
    Constructor with the reference to the XML configuration file.
    
    Parameters:
    
    xmlConfigRef - The URI reference to the XML configuration file.
  - Component
```
@Deprecated
public Component(Representation xmlConfigRepresentation)
```
    Deprecated.
    Use XML support in the Spring extension instead.
    
    Constructor with the representation of the XML configuration file.
    
    Parameters:
    
    xmlConfigRepresentation - The representation of the XML configuration file.
  - Component
```
@Deprecated
public Component(java.lang.String xmlConfigurationRef)
```
    Deprecated.
    Use XML support in the Spring extension instead.
    
    Constructor with the URI reference to the XML configuration file.
    
    Parameters:
    
    xmlConfigurationRef - The URI reference to the XML configuration file.
- Method Detail
  - main
```
@Deprecated
public static void main(java.lang.String[] args)
                 throws java.lang.Exception
```
    Deprecated.
    Use XML support in the Spring extension instead.
    
    Used as bootstrap for configuring and running a component in command line. Just provide as first and unique parameter the URI to the XML file. Note that relative paths are accepted.
    
    Parameters:
    
    args - The list of in-line parameters.
    
    Throws:
    
    java.lang.Exception
  - getClients
```
public ClientList getClients()
```
    Returns a modifiable list of client connectors.
    
    Returns:
    
    A modifiable list of client connectors.
  - getDefaultHost
```
public VirtualHost getDefaultHost()
```
    Returns the default virtual host.
    
    Returns:
    
    The default virtual host.
  - getHosts
```
public java.util.List<VirtualHost> getHosts()
```
    Returns the modifiable list of virtual hosts. Note that the order of virtual hosts in this list will be used to check the first one that matches.
    
    Returns:
    
    The modifiable list of virtual hosts.
  - getInternalRouter
```
public Router getInternalRouter()
```
    Returns the private internal router where Restlets like Applications can be attached. Those Restlets can be addressed via the Protocol.RIAP (Restlet Internal Access Protocol) client connector. This is used to manage private, internal and optimized access to local applications.
    
    The first use case is the modularization of a large application into modules or layers. This can also be achieved using the Context.getServerDispatcher() method, but the internal router is easily addressable via an URI scheme and can be fully private to the current Component.
    
    The second use case is the composition/mash-up of several representations via the org.restlet.ext.xml.Transformer class for example. For this you can leverage the XPath's document() function or the XSLT's include and import elements with RIAP URIs.
    
    Returns:
    
    The private internal router.
  - getLogService
```
public LogService getLogService()
```
    Returns the global log service. On the first call, if no log service was defined via the setLogService(LogService) method, then a default logger service is created. This service will be enabled by default and has a logger name composed the "org.restlet." prefix followed by the simple component class name (without packages), followed by the ".LogService" suffix.
    
    Returns:
    
    The global log service.
  - getRealm
```
public Realm getRealm(java.lang.String name)
```
    Finds the realm with the given name.
    
    Parameters:
    
    name - The name.
    
    Returns:
    
    The realm found or null.
  - getRealms
```
public java.util.List<Realm> getRealms()
```
    Returns the modifiable list of security realms.
    
    Returns:
    
    The modifiable list of security realms.
  - getServers
```
public ServerList getServers()
```
    Returns the modifiable list of server connectors.
    
    Returns:
    
    The modifiable list of server connectors.
  - getServices
```
public ServiceList getServices()
```
    Returns the modifiable list of services.
    
    Returns:
    
    The modifiable list of services.
  - getStatusService
```
@Deprecated
public StatusService getStatusService()
```
    Deprecated.
    Use Application.getStatusService() instead.
    
    Returns the status service, enabled by default.
    
    Returns:
    
    The status service.
  - getTaskService
```
public TaskService getTaskService()
```
    Returns a task service to run concurrent tasks. The service is enabled by default.
    
    Returns:
    
    A task service.
  - handle
```
public void handle(Request request,
                   Response response)
```
    Description copied from class: Restlet
    
    Handles a call. The default behavior is to initialize the Restlet by setting the current context using the Context.setCurrent(Context) method and by attempting to start it, unless it was already started. If an exception is thrown during the start action, then the response status is set to Status.SERVER_ERROR_INTERNAL.
    Subclasses overriding this method should make sure that they call super.handle(request, response) before adding their own logic.
    
    Specified by:
    
    handle in interface Uniform
    
    Overrides:
    
    handle in class Restlet
    
    Parameters:
    
    request - The request to handle.
    
    response - The response to update.
  - setClients
```
public void setClients(ClientList clients)
```
    Sets the modifiable list of client connectors. This method clears the current list and adds all entries in the parameter list.
    
    Parameters:
    
    clients - A list of client connectors.
  - setContext
```
public void setContext(Context context)
```
    Description copied from class: Restlet
    
    Sets the context.
    
    Overrides:
    
    setContext in class Restlet
    
    Parameters:
    
    context - The context.
  - setDefaultHost
```
public void setDefaultHost(VirtualHost defaultHost)
```
    Sets the default virtual host.
    
    Parameters:
    
    defaultHost - The default virtual host.
  - setHosts
```
public void setHosts(java.util.List<VirtualHost> hosts)
```
    Sets the modifiable list of virtual hosts. Note that the order of virtual hosts in this list will be used to check the first one that matches. This method clears the current list and adds all entries in the parameter list.
    
    Parameters:
    
    hosts - A list of virtual hosts.
  - setInternalRouter
```
public void setInternalRouter(Router internalRouter)
```
    Sets the private internal router were Restlets like Applications can be attached.
    
    Parameters:
    
    internalRouter - The private internal router.
    
    See Also:
    
    getInternalRouter()
  - setLogService
```
public void setLogService(LogService logService)
```
    Sets the global log service.
    
    Parameters:
    
    logService - The global log service.
  - setRealms
```
public void setRealms(java.util.List<Realm> realms)
```
    Sets the list of realms. This method clears the current list and adds all entries in the parameter list.
    
    Parameters:
    
    realms - A list of realms.
  - setServers
```
public void setServers(ServerList servers)
```
    Sets the modifiable list of server connectors. This method clears the current list and adds all entries in the parameter list.
    
    Parameters:
    
    servers - A list of server connectors.
  - setStatusService
```
@Deprecated
public void setStatusService(StatusService statusService)
```
    Deprecated.
    Use Application.setStatusService(StatusService) instead.
    
    Sets the status service.
    
    Parameters:
    
    statusService - The status service.
  - setTaskService
```
public void setTaskService(TaskService taskService)
```
    Sets the task service.
    
    Parameters:
    
    taskService - The task service.
  - start
```
public void start()
           throws java.lang.Exception
```
    Starts the component. First it starts all the connectors (clients then servers), the routers, the services, the realms and then the component's internal helper. Finally it calls the start method of the super class.
    
    Overrides:
    
    start in class Restlet
    
    Throws:
    
    java.lang.Exception
    
    See Also:
    
    startClients(), startServers(), startRouters(), startServices(), startRealms(), startHelper()
  - startClients
```
protected void startClients()
                     throws java.lang.Exception
```
    Starts the client connectors.
    
    Throws:
    
    java.lang.Exception
  - startHelper
```
protected void startHelper()
                    throws java.lang.Exception
```
    Starts the internal helper allowing incoming requests to be served.
    
    Throws:
    
    java.lang.Exception
  - startRealms
```
protected void startRealms()
                    throws java.lang.Exception
```
    Starts the realms.
    
    Throws:
    
    java.lang.Exception
  - startRouters
```
protected void startRouters()
                     throws java.lang.Exception
```
    Starts the virtual hosts and the internal router.
    
    Throws:
    
    java.lang.Exception
  - startServers
```
protected void startServers()
                     throws java.lang.Exception
```
    Starts the server connectors.
    
    Throws:
    
    java.lang.Exception
  - startServices
```
protected void startServices()
                      throws java.lang.Exception
```
    Starts the associated services.
    
    Throws:
    
    java.lang.Exception
  - stop
```
public void stop()
          throws java.lang.Exception
```
    Stops the component. First it stops the component's internal helper, the realms, the services, the routers and then stops all the connectors (servers then clients) Finally it calls the stop method of the super class.
    
    Overrides:
    
    stop in class Restlet
    
    Throws:
    
    java.lang.Exception
    
    See Also:
    
    stopHelper(), stopRealms(), stopServices(), stopRouters(), stopServers(), stopClients()
  - stopClients
```
protected void stopClients()
                    throws java.lang.Exception
```
    Stops the client connectors.
    
    Throws:
    
    java.lang.Exception
  - stopHelper
```
protected void stopHelper()
                   throws java.lang.Exception
```
    Stops the internal helper allowing incoming requests to be served.
    
    Throws:
    
    java.lang.Exception
  - stopRealms
```
protected void stopRealms()
                   throws java.lang.Exception
```
    Stops the realms.
    
    Throws:
    
    java.lang.Exception
  - stopRouters
```
protected void stopRouters()
                    throws java.lang.Exception
```
    Stops the virtual hosts and the internal router.
    
    Throws:
    
    java.lang.Exception
  - stopServers
```
protected void stopServers()
                    throws java.lang.Exception
```
    Stops the server connectors.
    
    Throws:
    
    java.lang.Exception
  - stopServices
```
protected void stopServices()
                     throws java.lang.Exception
```
    Stops the associated services.
    
    Throws:
    
    java.lang.Exception
  - updateHosts
```
public void updateHosts()
                 throws java.lang.Exception
```
    Updates the component to take into account changes to the virtual hosts. This method doesn't stop the connectors or the applications or Restlets attached to the virtual hosts. It just updates the internal routes between the virtual hosts and the attached Restlets or applications.
    
    Throws:
    
    java.lang.Exception

Class Component

Constructor Summary

Method Summary

Methods inherited from class org.restlet.Restlet

Methods inherited from class java.lang.Object

Constructor Detail

Component

Component

Component

Component

Method Detail

main

getClients

getDefaultHost

getHosts

getInternalRouter

getLogService

getRealm

getRealms

getServers

getServices

getStatusService

getTaskService

handle

setClients

setContext

setDefaultHost

setHosts

setInternalRouter

setLogService

setRealms

setServers

setStatusService

setTaskService

start

startClients

startHelper

startRealms

startRouters

startServers

startServices

stop

stopClients

stopHelper

stopRealms

stopRouters

stopServers

stopServices

updateHosts