Oh god, throwing a RedirectException does not always make sense, so

I made an even more general base class that throws a TimeoutException.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1199 6335cc39-0255-0410-8fd6-9bcaacd3b74c

projects/samskivert/src/java/com/samskivert/servlet/util/ServiceWaiter.java

@@ -1,37 +1,14 @@
 //
-// $Id: ServiceWaiter.java,v 1.2 2003/08/13 01:55:05 ray Exp $
+// $Id: ServiceWaiter.java,v 1.3 2003/08/15 02:23:47 ray Exp $
 
 package com.samskivert.servlet.util;
 
-import com.samskivert.Log;
 import com.samskivert.servlet.RedirectException;
-import com.samskivert.util.ResultListener;
 
 /**
- * A handy base class for issuing server-side service requests and
+ * Extends the basic ServiceWaiter to be useful for servlets.
- * awaiting their responses from within a servlet.
- *
- * <em>Note:</em> You might think that it would be keen to use this
- * anonymously like so:
- *
- * <pre>
- * ServiceWaiter waiter = new ServiceWaiter() {
- *     public void handleSuccess (int invid, ...) {
- *         // handle success
- *     }
- *     // ...
- * };
- * </pre>
- *
- * But that won't work because public methods in anonymous inner classes
- * do not have public visibility and so the invocation manager will not be
- * able to reflect your response methods when the time comes to deliver
- * the response. Unfortunately, there appears to be no manner in which to
- * instruct the Java compiler to give public scope to an anonymous inner
- * class rather than default scope. Sigh.
  */
-public class ServiceWaiter
+public class ServiceWaiter extends com.samskivert.util.ServiceWaiter
-    implements ResultListener
 {
     /** Timeout to specify when you don't want a timeout. Use at your own
      * risk. */
@@ -42,7 +19,7 @@ public class ServiceWaiter
      */
     public ServiceWaiter ()
     {
-        this(DEFAULT_WAITER_TIMEOUT);
+        super();
     }
 
     /**
@@ -52,56 +29,7 @@ public class ServiceWaiter
      */
     public ServiceWaiter (int timeout)
     {
-        setTimeout(timeout);
+        super(timeout);
-    }
-
-    /**
-     * Change the timeout being used for this ServiceWaiter after it
-     * has been constructed.
-     */
-    public void setTimeout (int timeout)
-    {
-        _timeout = timeout;
-    }
-
-    /**
-     * Reset the service waiter so that it can be used again.
-     */
-    public void reset ()
-    {
-        _success = 0;
-        _argument = null;
-    }
-
-    /**
-     * Marks the request as successful and posts the supplied response
-     * argument for perusal by the caller.
-     */
-    public synchronized void postSuccess (Object arg)
-    {
-        _success = 1;
-        _argument = arg;
-        notify();
-    }
-
-    /**
-     * Marks the request as failed and posts the supplied response
-     * argument for perusal by the caller.
-     */
-    public synchronized void postFailure (Object arg)
-    {
-        _success = -1;
-        _argument = arg;
-        notify();
-    }
-
-    /**
-     * Returns the argument posted by the waiter when the response
-     * arrived.
-     */
-    public Object getArgument ()
-    {
-        return _argument;
     }
 
     /**
@@ -110,33 +38,15 @@ public class ServiceWaiter
      * @return true if a success response was posted, false if a failure
      * repsonse was posted.
      */
-    public synchronized boolean awaitResponse ()
+    public boolean awaitResponse ()
         throws RedirectException
     {
-        while (_success == 0) {
+        try {
-            try {
+            return waitForResponse();
-                // wait for the response, timing out after a while
-                if (_timeout == NO_TIMEOUT) {
-                    wait();
 
-                } else {
+        } catch (TimeoutException te) {
-                    wait(1000L * _timeout);
+            throw new RedirectException(getTimeoutRedirectURL());
-                }
-
-                // if we get here without some sort of response, then
-                // we've timed out and we should freak out
-                if (_success == 0) {
-                    Log.warning("Service waiter timed out.");
-                    Thread.dumpStack();
-                    throw new RedirectException(getTimeoutRedirectURL());
-                }
-
-            } catch (InterruptedException ie) {
-                // fall through and wait again
-            }
         }
-
-        return (_success > 0);
     }
 
     /**
@@ -147,32 +57,4 @@ public class ServiceWaiter
         // TODO
         return "/";
     }
-
-    // documentation inherited from interface ResultListener
-    public void requestCompleted (Object result)
-    {
-        postSuccess(result);
-    }
-
-    // documentation inherited from interface ResultListener
-    public void requestFailed (Exception cause)
-    {
-        postFailure((cause != null) ? cause.getMessage() : null);
-    }
-
-    /** Whether or not the response succeeded; positive for success,
-     * negative for failure, zero means we haven't received the response
-     * yet. */
-    protected int _success = 0;
-
-    /** The argument posted by the waiter upon receipt of the response. */
-    protected Object _argument;
-
-    /** How many seconds to wait before giving up the ghost. */
-    protected int _timeout;
-
-    /** If a response is not received within the specified timeout, an
-     * exception is thrown which redirects the user to an internal error
-     * page. */
-    protected static final int DEFAULT_WAITER_TIMEOUT = 30;
 }

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

@@ -0,0 +1,175 @@
+//
+// $Id: ServiceWaiter.java,v 1.1 2003/08/15 02:23:47 ray Exp $
+
+package com.samskivert.util;
+
+import com.samskivert.Log;
+
+/**
+ * A handy base class for issuing server-side service requests and
+ * awaiting their responses from within a servlet.
+ *
+ * <em>Note:</em> You might think that it would be keen to use this
+ * anonymously like so:
+ *
+ * <pre>
+ * ServiceWaiter waiter = new ServiceWaiter() {
+ *     public void handleSuccess (int invid, ...) {
+ *         // handle success
+ *     }
+ *     // ...
+ * };
+ * </pre>
+ *
+ * But that won't work because public methods in anonymous inner classes
+ * do not have public visibility and so the invocation manager will not be
+ * able to reflect your response methods when the time comes to deliver
+ * the response. Unfortunately, there appears to be no manner in which to
+ * instruct the Java compiler to give public scope to an anonymous inner
+ * class rather than default scope. Sigh.
+ */
+public class ServiceWaiter
+    implements ResultListener
+{
+    /** Timeout to specify when you don't want a timeout. Use at your own
+     * risk. */
+    public static final int NO_TIMEOUT = -1;
+
+    public static class TimeoutException extends Exception
+    {
+        public TimeoutException ()
+        {
+            super("Timeout! Pow!");
+        }
+    }
+
+    /**
+     * Construct a ServiceWaiter with the default (30 second) timeout.
+     */
+    public ServiceWaiter ()
+    {
+        this(DEFAULT_WAITER_TIMEOUT);
+    }
+
+    /**
+     * Construct a ServiceWaiter with the specified timeout.
+     *
+     * @param timeout the timeout, in seconds.
+     */
+    public ServiceWaiter (int timeout)
+    {
+        setTimeout(timeout);
+    }
+
+    /**
+     * Change the timeout being used for this ServiceWaiter after it
+     * has been constructed.
+     */
+    public void setTimeout (int timeout)
+    {
+        _timeout = timeout;
+    }
+
+    /**
+     * Reset the service waiter so that it can be used again.
+     */
+    public void reset ()
+    {
+        _success = 0;
+        _argument = null;
+    }
+
+    /**
+     * Marks the request as successful and posts the supplied response
+     * argument for perusal by the caller.
+     */
+    public synchronized void postSuccess (Object arg)
+    {
+        _success = 1;
+        _argument = arg;
+        notify();
+    }
+
+    /**
+     * Marks the request as failed and posts the supplied response
+     * argument for perusal by the caller.
+     */
+    public synchronized void postFailure (Object arg)
+    {
+        _success = -1;
+        _argument = arg;
+        notify();
+    }
+
+    /**
+     * Returns the argument posted by the waiter when the response
+     * arrived.
+     */
+    public Object getArgument ()
+    {
+        return _argument;
+    }
+
+    /**
+     * Blocks waiting for the response.
+     *
+     * @return true if a success response was posted, false if a failure
+     * repsonse was posted.
+     */
+    public synchronized boolean waitForResponse ()
+        throws TimeoutException
+    {
+        while (_success == 0) {
+            try {
+                // wait for the response, timing out after a while
+                if (_timeout == NO_TIMEOUT) {
+                    wait();
+
+                } else {
+                    wait(1000L * _timeout);
+                }
+
+                // if we get here without some sort of response, then
+                // we've timed out and we should freak out
+                if (_success == 0) {
+                    Log.warning("Service waiter timed out.");
+                    Thread.dumpStack();
+                    throw new TimeoutException();
+                }
+
+            } catch (InterruptedException ie) {
+                // fall through and wait again
+            }
+        }
+
+        return (_success > 0);
+    }
+
+    // documentation inherited from interface ResultListener
+    public void requestCompleted (Object result)
+    {
+        postSuccess(result);
+    }
+
+    // documentation inherited from interface ResultListener
+    public void requestFailed (Exception cause)
+    {
+        postFailure((cause != null) ? cause.getMessage() : null);
+    }
+
+    /** Whether or not the response succeeded; positive for success,
+     * negative for failure, zero means we haven't received the response
+     * yet. */
+    protected int _success = 0;
+
+    /** The argument posted by the waiter upon receipt of the response. */
+    protected Object _argument;
+
+    /** How many seconds to wait before giving up the ghost. */
+    protected int _timeout;
+
+    /** If a response is not received within the specified timeout, an
+     * exception is thrown which redirects the user to an internal error
+     * page. */
+    protected static final int DEFAULT_WAITER_TIMEOUT = 30;
+}