AdminCallback.java
/*
** Module : AdminCallback.java
** Abstract : GWT AsyncCallback with extra features.
**
** Copyright (c) 2017, Golden Code Development Corporation.
**
** -#- -I- --Date-- --------------------------------Description-----------------------------------
** 001 HC 20170612 Initial version.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
** 1. No License To Use Trademarks.
**
** This license does not grant any license or rights to use the trademarks
** Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
** of Golden Code Development Corporation. You are not authorized to use the
** name Golden Code, FWD, or the names of any author or contributor, for
** publicity purposes without written authorization.
**
** 2. No Misrepresentation of Affiliation.
**
** You may not represent yourself as Golden Code Development Corporation or FWD.
**
** You may not represent yourself for publicity purposes as associated with
** Golden Code Development Corporation, FWD, or any author or contributor to
** the covered work, without written authorization.
**
** 3. No Misrepresentation of Source or Origin.
**
** You may not represent the covered work as solely your work. All modified
** versions of the covered work must be marked in a reasonable way to make it
** clear that the modified work is not originating from Golden Code Development
** Corporation or FWD. All modified versions must contain the notices of
** attribution required in this license.
*/
package com.goldencode.p2j.admin.client;
import com.goldencode.p2j.admin.client.application.*;
import com.goldencode.p2j.admin.shared.*;
import com.google.gwt.core.client.*;
import com.google.gwt.user.client.*;
import com.google.gwt.user.client.rpc.*;
import javax.inject.*;
import java.util.*;
import java.util.function.*;
import java.util.logging.*;
/**
* This class implements the standard {@link AsyncCallback} and provides some extended features
* on top - namely Admin specific error handling.
*/
public abstract class AdminCallback<T>
implements AsyncCallback<T>
{
/** Logger */
private static final Logger log = Logger.getLogger(AdminCallback.class.getSimpleName());
/** Reference to the admin service */
@Inject
private AdminServiceAsync adm;
/** Reference to the alarm service */
@Inject
private Alarm alarm;
/** Callback result */
private T result;
/** An exception thrown during the call */
private Throwable exception;
/** Server messages fetched from the backend on failure */
private List<String> serverMessages;
/**
* A default ctor to satisfy GWT.
*/
public AdminCallback()
{
}
/**
* Ctor.
*
* @param adm
* Reference to the admin service.
* @param alarm
* Reference to the alarm service.
*/
public AdminCallback(AdminServiceAsync adm, Alarm alarm)
{
this.adm = adm;
this.alarm = alarm;
}
/**
* Returns <code>true</code> when the call has finished and the result value is a success.
* "Is success" in this implementation means Boolean result value and result == true, but
* this can be overridden by the extending classes.
*
* @return <code>true</code> when the call has finished and the result value is a success,
* <code>false</code> otherwise.
*/
public boolean isSuccess()
{
return result != null && (!(result instanceof Boolean) || (Boolean) result);
}
/**
* Returns the callback result.
*
* @return callback result
*/
public T getResult()
{
return result;
}
/**
* Returns messages fetched from the admin service on failure.
*
* @return list of messages or an empty list if no messages
*/
public List<String> getServerMessages()
{
return serverMessages == null ? Collections.emptyList() : serverMessages;
}
/**
* Returns the exception thrown during the backend call.
*
* @return an exception instance or <code>null</code> if no exception
*/
public Throwable getException()
{
return exception;
}
/**
* Called when an asynchronous call fails to complete normally.
* {@link IncompatibleRemoteServiceException}s, {@link InvocationException}s,
* or checked exceptions thrown by the service method are examples of the type
* of failures that can be passed to this method.
* <p>
* If <code>caught</code> is an instance of an
* {@link IncompatibleRemoteServiceException} the application should try to
* get into a state where a browser refresh can be safely done.
* </p>
*
* @param caught
* failure encountered while executing a remote procedure call
*/
@Override
public void onFailure(Throwable caught)
{
if (caught instanceof StatusCodeException &&
((StatusCodeException) caught).getStatusCode() == 401)
{
Window.Location.replace(GWT.getHostPageBaseURL());
return;
}
exception = caught;
String msg = "Request error: " + caught.getMessage();
log.log(Level.SEVERE, "Request error:", caught);
if (alarm != null)
{
alarm.ring(msg, () -> onDone(null));
}
else
{
onDone(null);
}
}
/**
* Called when an asynchronous call completes successfully.
*
* @param result
* the return value of the remote produced call
*/
@Override
public void onSuccess(T result)
{
this.result = result;
if (adm != null && !isSuccess())
{
adm.getMessages(false, new AsyncCallback<String[][]>()
{
@Override
public void onFailure(Throwable caught)
{
log.log(Level.SEVERE, "Error retrieving messages from server", caught);
onDone(null);
}
@Override
public void onSuccess(String[][] result)
{
onDone(result);
}
private void onDone(String[][] messages)
{
if (messages != null)
{
serverMessages = new ArrayList<>();
for (String[] msgs : messages)
{
serverMessages.addAll(Arrays.asList(msgs));
}
if (alarm != null && !serverMessages.isEmpty())
{
alarm.ring(serverMessages, () -> AdminCallback.this.onDone(result));
return;
}
}
AdminCallback.this.onDone(result);
}
});
}
else
{
onDone(result);
}
}
/**
* Called when the service call has finished, regardless whether with success or failure.
*
* @param result
* The call result, <code>null</code> when failure.
*/
public abstract void onDone(T result);
}