Class ResourceLimitHandler

  • All Implemented Interfaces:
    Handler

    public class ResourceLimitHandler
    extends java.lang.Object
    implements Handler
    Handler for server resource management. This handler monitors various system load parameters, and rejects each request with a short message if any resource limit is exceeded. The properties are evaluated at init time, to minimize the per-request overhead of this monitor.

    Properties:

    memory
    The minimum # of remaining bytes available to the vm
    threads
    The Max number of active threads
    file
    The file name or resource of the html file to return if resources run low. Defaults to "busy.html".
    retry
    The number of seconds to request the client wait before retrying the request.
    Version:
    2.3
    Author:
    Stephen Uhler
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean init​(Server server, java.lang.String prefix)
      Initializes the handler.
      boolean respond​(Request request)
      Responds to an HTTP request.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • ResourceLimitHandler

        public ResourceLimitHandler()
    • Method Detail

      • init

        public boolean init​(Server server,
                            java.lang.String prefix)
        Description copied from interface: Handler
        Initializes the handler.
        Specified by:
        init in interface Handler
        Parameters:
        server - The HTTP server that created this Handler. Typical Handlers will use Server.props to obtain run-time configuration information.
        prefix - The handlers name. The string this Handler may prepend to all of the keys that it uses to extract configuration information from Server.props. This is set (by the Server and ChainHandler) to help avoid configuration parameter namespace collisions.
        Returns:
        true if this Handler initialized successfully, false otherwise. If false is returned, this Handler should not be used.
      • respond

        public boolean respond​(Request request)
                        throws java.io.IOException
        Description copied from interface: Handler
        Responds to an HTTP request.
        Specified by:
        respond in interface Handler
        Parameters:
        request - The Request object that represents the HTTP request.
        Returns:
        true if the request was handled. A request was handled if a response was supplied to the client, typically by calling Request.sendResponse() or Request.sendError.
        Throws:
        java.io.IOException - if there was an I/O error while sending the response to the client. Typically, in that case, the Server will (try to) send an error message to the client and then close the client's connection.

        The IOException should not be used to silently ignore problems such as being unable to access some server-side resource (for example getting a FileNotFoundException due to not being able to open a file). In that case, the Handler's duty is to turn that IOException into a HTTP response indicating, in this case, that a file could not be found.