Java Servlet Programming

Name

UnavailableException

Synopsis

Class Name: javax.servlet.UnavailableException

Superclass: javax.servlet.ServletException

Immediate Subclasses: None

Interfaces Implemented: None

Availability: Servlet API 1.0 and later

Description

A servlet can throw an UnavailableException at any time to indicate that it is not available to service client requests. There are two types of unavailability: permanent (where some corrective action must be taken on the server) and temporary. A servlet is temporarily unavailable if some system-wide problem momentarily prevents it from servicing requests. This may include network troubles or a crashed or overloaded database server. To mark a servlet as temporarily unavailable, specify a duration (in seconds) when constructing the exception. Well-written servers check back after this time. Servlet implementations are not required to treat temporary and permanent unavailability differently.

Servers generally provide clients with polite error messages when handling requests for unavailable servlets. For example, the Java Web Server returns a 404 (Unavailable) message.

Class Summary

public class UnavailableException extends ServletException {
  // Constructors
  public UnavailableException(int seconds, Servlet servlet, String msg);
  public UnavailableException(Servlet servlet, String msg);

  // Instance Methods
  public Servlet getServlet();
  public int getUnavailableSeconds();
  public boolean isPermanent();
}

Constructors

UnavailableException()

public UnavailableException(int ...