Two extensions of Invoker.Unit that encapsulate a pattern we frequently find

ourselves repeating.


git-svn-id: https://samskivert.googlecode.com/svn/trunk@1882 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/jdbc/RepositoryListenerUnit.java

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+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001-2006 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.jdbc;
+
+import com.samskivert.io.PersistenceException;
+import com.samskivert.util.ResultListener;
+
+/**
+ * Extends the {@link RepositoryUnit} and integrates with a {@link
+ * ResultListener}.
+ */
+public abstract class RepositoryListenerUnit<T> extends RepositoryUnit
+{
+    /**
+     * Creates a repository listener unit that will report its results to the
+     * supplied result listener.
+     */
+    public RepositoryListenerUnit (ResultListener<T> listener)
+    {
+        _listener = listener;
+    }
+
+    /**
+     * Called to perform our persistent action and generate our result.
+     */
+    public abstract T invokePersistResult ()
+        throws PersistenceException;
+
+    @Override // from RepositoryUnit
+    public void invokePersist ()
+        throws PersistenceException
+    {
+        _result = invokePersistResult();
+    }
+
+    @Override // from RepositoryUnit
+    public void handleSuccess ()
+    {
+        _listener.requestCompleted(_result);
+    }
+
+    @Override // from RepositoryUnit
+    public void handleFailure (PersistenceException pe)
+    {
+        _listener.requestFailed(pe);
+    }
+
+    protected ResultListener<T> _listener;
+    protected T _result;
+}

src/java/com/samskivert/jdbc/RepositoryUnit.java

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+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2001-2006 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.jdbc;
+
+import com.samskivert.io.PersistenceException;
+import com.samskivert.util.Invoker;
+
+/**
+ * Extends the {@link Invoker#Unit} and specializes it for doing database
+ * repository manipulation.
+ */
+public abstract class RepositoryUnit extends Invoker.Unit
+{
+    // from abstract Invoker.Unit
+    public boolean invoke ()
+    {
+        try {
+            invokePersist();
+        } catch (PersistenceException pe) {
+            _error = pe;
+        }
+        return true;
+    }
+
+    @Override // from Invoker.Unit
+    public void handleResult ()
+    {
+        if (_error != null) {
+            handleFailure(_error);
+        } else {
+            handleSuccess();
+        }
+    }
+
+    /**
+     * Called to perform our persistent actions.
+     */
+    public abstract void invokePersist ()
+        throws PersistenceException;
+
+    /**
+     * Called if our persistent actions have succeeded, back on the non-invoker
+     * thread.
+     */
+    public abstract void handleSuccess ();
+
+    /**
+     * Called if our persistent actions failed, back on the non-invoker thread.
+     */
+    public abstract void handleFailure (PersistenceException pe);
+
+    protected PersistenceException _error;
+}