HealthCheckValve (Apache Tomcat 9.0.118 API Documentation)
Description: declaration: package: org.apache.catalina.valves, class: HealthCheckValve

# Class HealthCheckValve

java.lang.Object
org.apache.catalina.util.LifecycleBase
org.apache.catalina.util.LifecycleMBeanBase
org.apache.catalina.valves.ValveBase
org.apache.catalina.valves.HealthCheckValve

All Implemented Interfaces:
  `MBeanRegistration, Contained, JmxEnabled, Lifecycle, Valve`

public class HealthCheckValve extends ValveBase
Simple Valve that responds to cloud orchestrators health checks.

- ## Nested Class Summary

  ### Nested classes/interfaces inherited from interface Lifecycle

  `Lifecycle.SingleUse`

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected boolean`
  `checkContainersAvailable`
  Check if all child containers are available.
  `protected boolean`
  `context`
  Will be set to true if the valve is associated with a context.

  ### Fields inherited from class ValveBase

  `asyncSupported, container, containerLog, next, sm`

  ### Fields inherited from class LifecycleMBeanBase

  `mserver`

  ### Fields inherited from interface 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`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `HealthCheckValve()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `boolean`
  `getCheckContainersAvailable()`
  `final String`
  `getPath()`
  `void`
  `invoke(Request request, Response response)`
  Perform request processing as required by this Valve.
  `protected boolean`
  `isAvailable(Container container)`
  `void`
  `setCheckContainersAvailable(boolean checkContainersAvailable)`
  `final void`
  `setPath(String path)`
  `protected void`
  `startInternal()`
  Start this component and implement the requirements of `LifecycleBase.startInternal()`.

  ### Methods inherited from class ValveBase

  `backgroundProcess, getContainer, getDomainInternal, getNext, getObjectNameKeyProperties, initInternal, isAsyncSupported, setAsyncSupported, setContainer, setNext, stopInternal, toString`

  ### Methods inherited from class LifecycleMBeanBase

  `destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister, unregister`

  ### Methods inherited from class LifecycleBase

  `addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, getThrowOnFailure, init, removeLifecycleListener, setState, setState, setThrowOnFailure, start, stop`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- ## Field Details

  - ### context

    protected boolean context
    Will be set to true if the valve is associated with a context.

  - ### checkContainersAvailable

    protected boolean checkContainersAvailable
    Check if all child containers are available.

- ## Constructor Details

  - ### HealthCheckValve

    public HealthCheckValve()

- ## Method Details

  - ### getPath

    public final String getPath()

  - ### setPath

    public final void setPath(String path)

  - ### getCheckContainersAvailable

    public boolean getCheckContainersAvailable()

  - ### setCheckContainersAvailable

    public void setCheckContainersAvailable(boolean checkContainersAvailable)

  - ### startInternal

    protected void startInternal() throws LifecycleException
    Description copied from class: `ValveBase`
    Start this component and implement the requirements of `LifecycleBase.startInternal()`.
    Overrides:
      `startInternal` in class `ValveBase`
    Throws:
      `LifecycleException` - if this component detects a fatal error that prevents this component from being used

  - ### invoke

    public void invoke(Request request, Response response) throws IOException, ServletException
    Description copied from interface: `Valve`

    Perform request processing as required by this Valve.

    An individual Valve MAY perform the following actions, in the specified order:

    - Examine and/or modify the properties of the specified Request and Response.
    - Examine the properties of the specified Request, completely generate the corresponding Response, and return control to the caller.
    - Examine the properties of the specified Request and Response, wrap either or both of these objects to supplement their functionality, and pass them on.
    - If the corresponding Response was not generated (and control was not returned), call the next Valve in the pipeline (if there is one) by executing `getNext().invoke()`.
    - Examine, but not modify, the properties of the resulting Response (which was created by a subsequently invoked Valve or Container).

    A Valve MUST NOT do any of the following things:

    - Change request properties that have already been used to direct the flow of processing control for this request (for instance, trying to change the virtual host to which a Request should be sent from a pipeline attached to a Host or Context in the standard implementation).
    - Create a completed Response AND pass this Request and Response on to the next Valve in the pipeline.
    - Consume bytes from the input stream associated with the Request, unless it is completely generating the response, or wrapping the request before passing it on.
    - Modify the HTTP headers included with the Response after the `getNext().invoke()` method has returned.
    - Perform any actions on the output stream associated with the specified Response after the `getNext().invoke()` method has returned.
    Parameters:
      `request` - The servlet request to be processed
      `response` - The servlet response to be created
    Throws:
      `IOException` - if an input/output error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet
      `ServletException` - if a servlet error occurs, or is thrown by a subsequently invoked Valve, Filter, or Servlet

  - ### isAvailable

    protected boolean isAvailable(Container container)