javax.servlet
クラス UnavailableException

java.lang.Object
  |
  +--java.lang.Throwable
        |
        +--java.lang.Exception
              |
              +--javax.servlet.ServletException
                    |
                    +--javax.servlet.UnavailableException
すべての実装インタフェース:
java.io.Serializable

public class UnavailableException
extends ServletException

Defines an exception that a servlet or filter throws to indicate that it is permanently or temporarily unavailable.

When a servlet or filter is permanently unavailable, something is wrong with the it, and it cannot handle requests until some action is taken. For example, a servlet might be configured incorrectly, or a filter's state may be corrupted. The component should log both the error and the corrective action that is needed.

A servlet or filter is temporarily unavailable if it cannot handle requests momentarily due to some system-wide problem. For example, a third-tier server might not be accessible, or there may be insufficient memory or disk storage to handle requests. A system administrator may need to take corrective action.

Servlet containers can safely treat both types of unavailable exceptions in the same way. However, treating temporary unavailability effectively makes the servlet container more robust. Specifically, the servlet container might block requests to the servlet or filter for a period of time suggested by the exception, rather than rejecting them until the servlet container restarts.

バージョン:
$Version$
作成者:
Various
関連項目:
直列化された形式

コンストラクタの概要
UnavailableException(int seconds, Servlet servlet, java.lang.String msg)
          推奨されていません。 As of Java Servlet API 2.2, use UnavailableException(String, int) instead.
UnavailableException(Servlet servlet, java.lang.String msg)
          推奨されていません。 As of Java Servlet API 2.2, use UnavailableException(String) instead.
UnavailableException(java.lang.String msg)
          Constructs a new exception with a descriptive message indicating that the servlet is permanently unavailable.
UnavailableException(java.lang.String msg, int seconds)
          Constructs a new exception with a descriptive message indicating that the servlet is temporarily unavailable and giving an estimate of how long it will be unavailable.
 
メソッドの概要
 Servlet getServlet()
          推奨されていません。 As of Java Servlet API 2.2, with no replacement. Returns the servlet that is reporting its unavailability.
 int getUnavailableSeconds()
          Returns the number of seconds the servlet expects to be temporarily unavailable.
 boolean isPermanent()
          Returns a boolean indicating whether the servlet is permanently unavailable.
 
クラス javax.servlet.ServletException から継承したメソッド
getRootCause
 
クラス java.lang.Throwable から継承したメソッド
fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString
 
クラス java.lang.Object から継承したメソッド
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

コンストラクタの詳細

UnavailableException

public UnavailableException(Servlet servlet,
                            java.lang.String msg)
推奨されていません。 As of Java Servlet API 2.2, use UnavailableException(String) instead.

パラメータ:
servlet - the Servlet instance that is unavailable
msg - a String specifying the descriptive message

UnavailableException

public UnavailableException(int seconds,
                            Servlet servlet,
                            java.lang.String msg)
推奨されていません。 As of Java Servlet API 2.2, use UnavailableException(String, int) instead.

パラメータ:
seconds - an integer specifying the number of seconds the servlet expects to be unavailable; if zero or negative, indicates that the servlet can't make an estimate
servlet - the Servlet that is unavailable
msg - a String specifying the descriptive message, which can be written to a log file or displayed for the user.

UnavailableException

public UnavailableException(java.lang.String msg)
Constructs a new exception with a descriptive message indicating that the servlet is permanently unavailable.

パラメータ:
msg - a String specifying the descriptive message

UnavailableException

public UnavailableException(java.lang.String msg,
                            int seconds)
Constructs a new exception with a descriptive message indicating that the servlet is temporarily unavailable and giving an estimate of how long it will be unavailable.

In some cases, the servlet cannot make an estimate. For example, the servlet might know that a server it needs is not running, but not be able to report how long it will take to be restored to functionality. This can be indicated with a negative or zero value for the seconds argument.

パラメータ:
msg - a String specifying the descriptive message, which can be written to a log file or displayed for the user.
seconds - an integer specifying the number of seconds the servlet expects to be unavailable; if zero or negative, indicates that the servlet can't make an estimate
メソッドの詳細

isPermanent

public boolean isPermanent()
Returns a boolean indicating whether the servlet is permanently unavailable. If so, something is wrong with the servlet, and the system administrator must take some corrective action.

戻り値:
true if the servlet is permanently unavailable; false if the servlet is available or temporarily unavailable

getServlet

public Servlet getServlet()
推奨されていません。 As of Java Servlet API 2.2, with no replacement. Returns the servlet that is reporting its unavailability.

戻り値:
the Servlet object that is throwing the UnavailableException

getUnavailableSeconds

public int getUnavailableSeconds()
Returns the number of seconds the servlet expects to be temporarily unavailable.

If this method returns a negative number, the servlet is permanently unavailable or cannot provide an estimate of how long it will be unavailable. No effort is made to correct for the time elapsed since the exception was first reported.

戻り値:
an integer specifying the number of seconds the servlet will be temporarily unavailable, or a negative number if the servlet is permanently unavailable or cannot make an estimate


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