Created a runtime exception that can be thrown if for some reason a

service can't make its services available (like the database is down, or
their team lost, or their girlfriend turned out to be a guy).


git-svn-id: https://samskivert.googlecode.com/svn/trunk@406 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/util/ServiceUnavailableException.java

@@ -0,0 +1,67 @@
+//
+// $Id: ServiceUnavailableException.java,v 1.1 2001/11/01 01:15:18 mdb Exp $
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.util;
+
+import org.apache.commons.util.exception.NestableRuntimeException;
+
+/**
+ * The service unavailable exception can be thrown by any service that
+ * relies on some other services which is currently not available. If a
+ * service, for example, required information from a database and the
+ * underlying database service failed, it might wish to throw a service
+ * unavailable exception rather than provide invalid data to the caller.
+ *
+ * <p> Because this is a runtime exception, it is expected that it would
+ * only be thrown in unsalvagable situations and with the knowledge that
+ * some entity in the calling application would eventually catch and
+ * report the exception in as sensible way as possible (it is in the same
+ * class of error recovery as if our service threw a
+ * <code>NullPointerException</code>).
+ */
+public class ServiceUnavailableException extends NestableRuntimeException
+{
+    /**
+     * Constructs a service unavailable exception with the specified error
+     * message.
+     */
+    public ServiceUnavailableException (String message)
+    {
+        super(message);
+    }
+
+    /**
+     * Constructs a service unavailable exception with the specified error
+     * message and the chained causing event.
+     */
+    public ServiceUnavailableException (String message, Exception cause)
+    {
+        super(message, cause);
+    }
+
+    /**
+     * Constructs a service unavailable exception with the specified
+     * chained causing event.
+     */
+    public ServiceUnavailableException (Exception cause)
+    {
+        super(cause);
+    }
+}