diff --git a/src/java/com/threerings/presents/util/PersistingUnit.java b/src/java/com/threerings/presents/util/PersistingUnit.java new file mode 100644 index 000000000..c70d94152 --- /dev/null +++ b/src/java/com/threerings/presents/util/PersistingUnit.java @@ -0,0 +1,101 @@ +// +// $Id$ +// +// Narya library - tools for developing networked games +// Copyright (C) 2002-2005 Three Rings Design, Inc., All Rights Reserved +// http://www.threerings.net/code/narya/ +// +// 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.threerings.presents.util; + +import com.samskivert.io.PersistenceException; +import com.samskivert.util.Invoker; + +import com.threerings.presents.Log; +import com.threerings.presents.client.InvocationService; +import com.threerings.presents.data.InvocationCodes; + +/** + * Simplifies a common pattern which is to post an {@link Invoker} unit which + * does some database operation and then calls back to an {@link + * InvocationService.InvocationListener} of some sort. If the database operation + * fails, the error will be logged and the result listener will be replied to + * with {@link InvocationCodes#INTERNAL_ERROR}. + */ +public abstract class PersistingUnit extends Invoker.Unit +{ + public PersistingUnit (InvocationService.InvocationListener listener) + { + _listener = listener; + } + + /** + * This method is where the unit performs its persistent actions. Any + * persistence exception will be caught and logged along with the output + * from {@link #getFailureMessage}, if any. + */ + public abstract void invokePersistent () + throws PersistenceException; + + /** + * Handles the success case, which by default is to do nothing. + */ + public void handleSuccess () + { + } + + /** + * Handles the failure case by logging the error and reporting an internal + * error to the listener. + */ + public void handleFailure (PersistenceException error) + { + Log.warning(getFailureMessage()); + Log.logStackTrace(error); + _listener.requestFailed(InvocationCodes.INTERNAL_ERROR); + } + + /** + * Provides a custom failure message in the event that the persistent + * action fails. This will be logged along with the exception. + */ + public String getFailureMessage () + { + return this + " failed."; + } + + public boolean invoke () + { + try { + invokePersistent(); + } catch (PersistenceException pe) { + _error = pe; + } + return true; + } + + public void handleResult () + { + if (_error != null) { + handleFailure(_error); + } else { + handleSuccess(); + } + } + + protected InvocationService.InvocationListener _listener; + protected PersistenceException _error; +}