unavailableexception.html

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Java 2 Platform EE v1.3: Class  UnavailableException
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javax.servlet</FONT>
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Class  UnavailableException</H2>
<PRE>
java.lang.Object
  |
  +--java.lang.Throwable
        |
        +--java.lang.Exception
              |
              +--<A HREF="../../javax/servlet/ServletException.html">javax.servlet.ServletException</A>
                    |
                    +--<B>javax.servlet.UnavailableException</B>
</PRE>
<DL>
<DT><B>All Implemented Interfaces:</B> <DD>java.io.Serializable</DD>
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<DT>public class <B>UnavailableException</B><DT>extends <A HREF="../../javax/servlet/ServletException.html">ServletException</A></DL>

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

 <p>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.

 <p>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.

 <p>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.
<P>
<DL>
<DT><B>See Also: </B><DD><A HREF="../../serialized-form.html#javax.servlet.UnavailableException">Serialized Form</A></DL>
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<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(int, javax.servlet.Servlet, java.lang.String)">UnavailableException</A></B>(int&nbsp;seconds,
                     <A HREF="../../javax/servlet/Servlet.html">Servlet</A>&nbsp;servlet,
                     java.lang.String&nbsp;msg)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Deprecated.</B>&nbsp;<I>As of Java Servlet API 2.2, use <A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(java.lang.String, int)"><CODE>UnavailableException(String, int)</CODE></A> instead.</I></TD>
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<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(javax.servlet.Servlet, java.lang.String)">UnavailableException</A></B>(<A HREF="../../javax/servlet/Servlet.html">Servlet</A>&nbsp;servlet,
                     java.lang.String&nbsp;msg)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Deprecated.</B>&nbsp;<I>As of Java Servlet API 2.2, use <A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(java.lang.String)"><CODE>UnavailableException(String)</CODE></A> instead.</I></TD>
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<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(java.lang.String)">UnavailableException</A></B>(java.lang.String&nbsp;msg)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Constructs a new exception with a descriptive
 message indicating that the servlet is permanently
 unavailable.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#UnavailableException(java.lang.String, int)">UnavailableException</A></B>(java.lang.String&nbsp;msg,
                     int&nbsp;seconds)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;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.</TD>
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<CODE>&nbsp;<A HREF="../../javax/servlet/Servlet.html">Servlet</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#getServlet()">getServlet</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Deprecated.</B>&nbsp;<I>As of Java Servlet API 2.2, with no replacement.

 Returns the servlet that is reporting its unavailability.</I></TD>
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<CODE>&nbsp;int</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#getUnavailableSeconds()">getUnavailableSeconds</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returns the number of seconds the servlet expects to 
 be temporarily unavailable.</TD>
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<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;boolean</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/servlet/UnavailableException.html#isPermanent()">isPermanent</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returns a <code>boolean</code> indicating
 whether the servlet is permanently unavailable.</TD>
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<TD><B>Methods inherited from class javax.servlet.<A HREF="../../javax/servlet/ServletException.html">ServletException</A></B></TD>
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<TD><CODE><A HREF="../../javax/servlet/ServletException.html#getRootCause()">getRootCause</A></CODE></TD>
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<TD><B>Methods inherited from class java.lang.Throwable</B></TD>
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<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE>fillInStackTrace, getLocalizedMessage, getMessage, printStackTrace, printStackTrace, printStackTrace, toString</CODE></TD>
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