Wrapper (Apache Tomcat 8.0.53 API Documentation)

All Superinterfaces:

Container, Lifecycle

All Known Implementing Classes:

StandardWrapper, Tomcat.ExistingStandardWrapper
```
public interface Wrapper
extends Container
```
A Wrapper is a Container that represents an individual servlet definition from the deployment descriptor of the web application. It provides a convenient mechanism to use Interceptors that see every single request to the servlet represented by this definition.
Implementations of Wrapper are responsible for managing the servlet life cycle for their underlying servlet class, including calling init() and destroy() at appropriate times, as well as respecting the existence of the SingleThreadModel declaration on the servlet class itself.
The parent Container attached to a Wrapper will generally be an implementation of Context, representing the servlet context (and therefore the web application) within which this servlet executes.
Child Containers are not allowed on Wrapper implementations, so the addChild() method should throw an IllegalArgumentException.

Author:

Craig R. McClanahan

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle
  Lifecycle.SingleUse

Field Summary

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`ADD_MAPPING_EVENT` Container event for adding a wrapper.
`static java.lang.String`	`REMOVE_MAPPING_EVENT` Container event for removing a wrapper.

Fields inherited from interface org.apache.catalina.Container
ADD_CHILD_EVENT, ADD_VALVE_EVENT, REMOVE_CHILD_EVENT, REMOVE_VALVE_EVENT

Fields inherited from interface org.apache.catalina.Lifecycle
AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`addInitParameter(java.lang.String name, java.lang.String value)` Add a new servlet initialization parameter for this servlet.
`void`	`addInstanceListener(InstanceListener listener)` Deprecated. Will be removed in 8.5.x onwards
`void`	`addMapping(java.lang.String mapping)` Add a mapping associated with the Wrapper.
`void`	`addSecurityReference(java.lang.String name, java.lang.String link)` Add a new security role reference record to the set of records for this servlet.
`Servlet`	`allocate()` Allocate an initialized instance of this Servlet that is ready to have its `service()` method called.
`void`	`deallocate(Servlet servlet)` Return this previously allocated servlet to the pool of available instances.
`java.lang.String`	`findInitParameter(java.lang.String name)` Return the value for the specified initialization parameter name, if any; otherwise return `null`.
`java.lang.String[]`	`findInitParameters()` Return the names of all defined initialization parameters for this servlet.
`java.lang.String[]`	`findMappings()` Return the mappings associated with this wrapper.
`java.lang.String`	`findSecurityReference(java.lang.String name)` Return the security role link for the specified security role reference name, if any; otherwise return `null`.
`java.lang.String[]`	`findSecurityReferences()` Return the set of security role reference names associated with this servlet, if any; otherwise return a zero-length array.
`long`	`getAvailable()` Return the available date/time for this servlet, in milliseconds since the epoch.
`int`	`getLoadOnStartup()` Return the load-on-startup order value (negative value means load on first call).
`MultipartConfigElement`	`getMultipartConfigElement()` Get the multi-part configuration for the associated servlet.
`java.lang.String`	`getRunAs()` Return the run-as identity for this servlet.
`Servlet`	`getServlet()` Return the associated servlet instance.
`java.lang.String`	`getServletClass()` Return the fully qualified servlet class name for this servlet.
`java.lang.String[]`	`getServletMethods()` Gets the names of the methods supported by the underlying servlet.
`void`	`incrementErrorCount()` Increment the error count value used when monitoring.
`boolean`	`isAsyncSupported()` Does the associated Servlet support async processing?
`boolean`	`isEnabled()` Is the associated Servlet enabled?
`boolean`	`isOverridable()` Is the Servlet overridable by a ServletContainerInitializer?
`boolean`	`isUnavailable()` Is this servlet currently unavailable?
`void`	`load()` Load and initialize an instance of this servlet, if there is not already at least one initialized instance.
`void`	`removeInitParameter(java.lang.String name)` Remove the specified initialization parameter from this servlet.
`void`	`removeInstanceListener(InstanceListener listener)` Deprecated. Will be removed in 8.5.x onwards
`void`	`removeMapping(java.lang.String mapping)` Remove a mapping associated with the wrapper.
`void`	`removeSecurityReference(java.lang.String name)` Remove any security role reference for the specified role name.
`void`	`servletSecurityAnnotationScan()` Deprecated. This will be removed in Tomcat 9.
`void`	`setAsyncSupported(boolean asyncSupport)` Set the async support for the associated servlet.
`void`	`setAvailable(long available)` Set the available date/time for this servlet, in milliseconds since the epoch.
`void`	`setEnabled(boolean enabled)` Sets the enabled attribute for the associated servlet.
`void`	`setLoadOnStartup(int value)` Set the load-on-startup order value (negative value means load on first call).
`void`	`setMultipartConfigElement(MultipartConfigElement multipartConfig)` Set the multi-part configuration for the associated servlet.
`void`	`setOverridable(boolean overridable)` Sets the overridable attribute for this Servlet.
`void`	`setRunAs(java.lang.String runAs)` Set the run-as identity for this servlet.
`void`	`setServlet(Servlet servlet)` Set the associated servlet instance
`void`	`setServletClass(java.lang.String servletClass)` Set the fully qualified servlet class name for this servlet.
`void`	`setServletSecurityAnnotationScanRequired(boolean b)` Deprecated. This will be removed in Tomcat 9.
`void`	`unavailable(UnavailableException unavailable)` Process an UnavailableException, marking this servlet as unavailable for the specified amount of time.
`void`	`unload()` Unload all initialized instances of this servlet, after calling the `destroy()` method for each instance.

Methods inherited from interface org.apache.catalina.Lifecycle
addLifecycleListener, destroy, findLifecycleListeners, getState, getStateName, init, removeLifecycleListener, start, stop

- Field Detail
  - ADD_MAPPING_EVENT
```
static final java.lang.String ADD_MAPPING_EVENT
```
    Container event for adding a wrapper.
    
    See Also:
    Constant Field Values
  - REMOVE_MAPPING_EVENT
```
static final java.lang.String REMOVE_MAPPING_EVENT
```
    Container event for removing a wrapper.
    
    See Also:
    Constant Field Values
- Method Detail
  - getAvailable
```
long getAvailable()
```
    Return the available date/time for this servlet, in milliseconds since the epoch. If this date/time is in the future, any request for this servlet will return an SC_SERVICE_UNAVAILABLE error. If it is zero, the servlet is currently available. A value equal to Long.MAX_VALUE is considered to mean that unavailability is permanent.
  - setAvailable
```
void setAvailable(long available)
```
    Set the available date/time for this servlet, in milliseconds since the epoch. If this date/time is in the future, any request for this servlet will return an SC_SERVICE_UNAVAILABLE error. A value equal to Long.MAX_VALUE is considered to mean that unavailability is permanent.
    
    Parameters:
    available - The new available date/time
  - getLoadOnStartup
```
int getLoadOnStartup()
```
    Return the load-on-startup order value (negative value means load on first call).
  - setLoadOnStartup
```
void setLoadOnStartup(int value)
```
    Set the load-on-startup order value (negative value means load on first call).
    
    Parameters:
    value - New load-on-startup value
  - getRunAs
```
java.lang.String getRunAs()
```
    Return the run-as identity for this servlet.
  - setRunAs
```
void setRunAs(java.lang.String runAs)
```
    Set the run-as identity for this servlet.
    
    Parameters:
    runAs - New run-as identity value
  - getServletClass
```
java.lang.String getServletClass()
```
    Return the fully qualified servlet class name for this servlet.
  - setServletClass
```
void setServletClass(java.lang.String servletClass)
```
    Set the fully qualified servlet class name for this servlet.
    
    Parameters:
    servletClass - Servlet class name
  - getServletMethods
```
java.lang.String[] getServletMethods()
                                     throws ServletException
```
    Gets the names of the methods supported by the underlying servlet. This is the same set of methods included in the Allow response header in response to an OPTIONS request method processed by the underlying servlet.
    
    Returns:
    Array of names of the methods supported by the underlying servlet
    
    Throws:
    
    ServletException - If the target servlet can not be loaded
  - isUnavailable
```
boolean isUnavailable()
```
    Is this servlet currently unavailable?
  - getServlet
```
Servlet getServlet()
```
    Return the associated servlet instance.
  - setServlet
```
void setServlet(Servlet servlet)
```
    Set the associated servlet instance
  - addInitParameter
```
void addInitParameter(java.lang.String name,
                    java.lang.String value)
```
    Add a new servlet initialization parameter for this servlet.
    
    Parameters:
    name - Name of this initialization parameter to add
    value - Value of this initialization parameter to add
  - addInstanceListener
```
@Deprecated
void addInstanceListener(InstanceListener listener)
```
    Deprecated. Will be removed in 8.5.x onwards
    
    Add a new listener interested in InstanceEvents.
    
    Parameters:
    listener - The new listener
  - addMapping
```
void addMapping(java.lang.String mapping)
```
    Add a mapping associated with the Wrapper.
    
    Parameters:
    mapping - The new wrapper mapping
  - addSecurityReference
```
void addSecurityReference(java.lang.String name,
                        java.lang.String link)
```
    Add a new security role reference record to the set of records for this servlet.
    
    Parameters:
    name - Role name used within this servlet
    link - Role name used within the web application
  - allocate
```
Servlet allocate()
                 throws ServletException
```
    Allocate an initialized instance of this Servlet that is ready to have its service() method called. If the servlet class does not implement SingleThreadModel, the (only) initialized instance may be returned immediately. If the servlet class implements SingleThreadModel, the Wrapper implementation must ensure that this instance is not allocated again until it is deallocated by a call to deallocate().
    
    Throws:
    
    ServletException - if the servlet init() method threw an exception
    
    ServletException - if a loading error occurs
  - deallocate
```
void deallocate(Servlet servlet)
                throws ServletException
```
    Return this previously allocated servlet to the pool of available instances. If this servlet class does not implement SingleThreadModel, no action is actually required.
    
    Parameters:
    servlet - The servlet to be returned
    
    Throws:
    
    ServletException - if a deallocation error occurs
  - findInitParameter
```
java.lang.String findInitParameter(java.lang.String name)
```
    Return the value for the specified initialization parameter name, if any; otherwise return null.
    
    Parameters:
    name - Name of the requested initialization parameter
  - findInitParameters
```
java.lang.String[] findInitParameters()
```
    Return the names of all defined initialization parameters for this servlet.
  - findMappings
```
java.lang.String[] findMappings()
```
    Return the mappings associated with this wrapper.
  - findSecurityReference
```
java.lang.String findSecurityReference(java.lang.String name)
```
    Return the security role link for the specified security role reference name, if any; otherwise return null.
    
    Parameters:
    name - Security role reference used within this servlet
  - findSecurityReferences
```
java.lang.String[] findSecurityReferences()
```
    Return the set of security role reference names associated with this servlet, if any; otherwise return a zero-length array.
  - incrementErrorCount
```
void incrementErrorCount()
```
    Increment the error count value used when monitoring.
  - load
```
void load()
          throws ServletException
```
    Load and initialize an instance of this servlet, if there is not already at least one initialized instance. This can be used, for example, to load servlets that are marked in the deployment descriptor to be loaded at server startup time.
    
    Throws:
    
    ServletException - if the servlet init() method threw an exception
    
    ServletException - if some other loading problem occurs
  - removeInitParameter
```
void removeInitParameter(java.lang.String name)
```
    Remove the specified initialization parameter from this servlet.
    
    Parameters:
    name - Name of the initialization parameter to remove
  - removeInstanceListener
```
@Deprecated
void removeInstanceListener(InstanceListener listener)
```
    Deprecated. Will be removed in 8.5.x onwards
    
    Remove a listener no longer interested in InstanceEvents.
    
    Parameters:
    listener - The listener to remove
  - removeMapping
```
void removeMapping(java.lang.String mapping)
```
    Remove a mapping associated with the wrapper.
    
    Parameters:
    mapping - The pattern to remove
  - removeSecurityReference
```
void removeSecurityReference(java.lang.String name)
```
    Remove any security role reference for the specified role name.
    
    Parameters:
    name - Security role used within this servlet to be removed
  - unavailable
```
void unavailable(UnavailableException unavailable)
```
    Process an UnavailableException, marking this servlet as unavailable for the specified amount of time.
    
    Parameters:
    unavailable - The exception that occurred, or null to mark this servlet as permanently unavailable
  - unload
```
void unload()
            throws ServletException
```
    Unload all initialized instances of this servlet, after calling the destroy() method for each instance. This can be used, for example, prior to shutting down the entire servlet engine, or prior to reloading all of the classes from the Loader associated with our Loader's repository.
    
    Throws:
    
    ServletException - if an unload error occurs
  - getMultipartConfigElement
```
MultipartConfigElement getMultipartConfigElement()
```
    Get the multi-part configuration for the associated servlet. If no multi-part configuration has been defined, then null will be returned.
  - setMultipartConfigElement
```
void setMultipartConfigElement(MultipartConfigElement multipartConfig)
```
    Set the multi-part configuration for the associated servlet. To clear the multi-part configuration specify null as the new value.
  - isAsyncSupported
```
boolean isAsyncSupported()
```
    Does the associated Servlet support async processing? Defaults to false.
  - setAsyncSupported
```
void setAsyncSupported(boolean asyncSupport)
```
    Set the async support for the associated servlet.
  - isEnabled
```
boolean isEnabled()
```
    Is the associated Servlet enabled? Defaults to true.
  - setEnabled
```
void setEnabled(boolean enabled)
```
    Sets the enabled attribute for the associated servlet.
  - setServletSecurityAnnotationScanRequired
```
@Deprecated
void setServletSecurityAnnotationScanRequired(boolean b)
```
    Deprecated. This will be removed in Tomcat 9.
    
    This method is no longer used. All implementations should be NO-OPs.
    
    Parameters:
    b - Unused.
  - servletSecurityAnnotationScan
```
@Deprecated
void servletSecurityAnnotationScan()
                                   throws ServletException
```
    Deprecated. This will be removed in Tomcat 9.
    
    This method is no longer used. All implementations should be NO-OPs.
    
    Throws:
    
    ServletException - Never thrown
  - isOverridable
```
boolean isOverridable()
```
    Is the Servlet overridable by a ServletContainerInitializer?
  - setOverridable
```
void setOverridable(boolean overridable)
```
    Sets the overridable attribute for this Servlet.

Interface Wrapper

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle

Field Summary

Fields inherited from interface org.apache.catalina.Container

Fields inherited from interface org.apache.catalina.Lifecycle

Method Summary

Methods inherited from interface org.apache.catalina.Container

Methods inherited from interface org.apache.catalina.Lifecycle

Field Detail

ADD_MAPPING_EVENT

REMOVE_MAPPING_EVENT

Method Detail

getAvailable

setAvailable

getLoadOnStartup

setLoadOnStartup

getRunAs

setRunAs

getServletClass

setServletClass

getServletMethods

isUnavailable

getServlet

setServlet

addInitParameter

addInstanceListener

addMapping

addSecurityReference

allocate

deallocate

findInitParameter

findInitParameters

findMappings

findSecurityReference

findSecurityReferences

incrementErrorCount

load

removeInitParameter

removeInstanceListener

removeMapping

removeSecurityReference

unavailable

unload

getMultipartConfigElement

setMultipartConfigElement

isAsyncSupported

setAsyncSupported

isEnabled

setEnabled

setServletSecurityAnnotationScanRequired

servletSecurityAnnotationScan

isOverridable

setOverridable