/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.wicketinaction.charts;
import java.util.Random;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import org.apache.wicket.Application;
import org.apache.wicket.protocol.ws.IWebSocketSettings;
import org.apache.wicket.protocol.ws.api.IWebSocketConnection;
import org.apache.wicket.protocol.ws.api.message.ConnectedMessage;
import org.apache.wicket.protocol.ws.api.registry.IKey;
import org.apache.wicket.protocol.ws.api.registry.IWebSocketConnectionRegistry;
/**
* A helper class that uses the web connection to push data to the
* client.
* To keep the demo simpler it doesn't use #onClose() to stop
* the thread.
*/
public class ChartUpdater
{
public static void start(ConnectedMessage message)
{
Record[] data = generateData();
// create an asynchronous task that will write the data to the client
UpdateTask updateTask = new UpdateTask(message.getApplication(), message.getSessionId(), message.getKey(), data);
Executors.newScheduledThreadPool(1).schedule(updateTask, 1, TimeUnit.SECONDS);
}
/**
* Generates some random data to send to the client
* @return records with random data
*/
private static Record[] generateData()
{
Random randomGenerator = new Random();
Record[] data = new Record[1000];
for (int i = 0; i < 1000; i++)
{
Record r = new Record();
r.year = 2000 + i;
r.field = (i % 2 == 0) ? "Company 1" : "Company 2";
r.value = randomGenerator.nextInt(1500);
data[i] = r;
}
return data;
}
/**
* A task that sends data to the client by pushing it to the web socket connection
*/
private static class UpdateTask implements Runnable
{
private static final String JSON_SKELETON = "{ \"year\": \"%s\", \"field\": \"%s\", \"value\": %s }";
/**
* The following fields are needed to be able to lookup the IWebSocketConnection from
* IWebSocketConnectionRegistry
*/
private final String applicationName;
private final String sessionId;
private final IKey key;
/**
* The data that has to be sent to the client
*/
private final Record[] data;
private UpdateTask(Application application, String sessionId, IKey key, Record[] data)
{
this.applicationName = application.getName();
this.sessionId = sessionId;
this.key = key;
this.data = data;
}
@Override
public void run()
{
Application application = Application.get(applicationName);
IWebSocketSettings webSocketSettings = IWebSocketSettings.Holder.get(application);
IWebSocketConnectionRegistry webSocketConnectionRegistry = webSocketSettings.getConnectionRegistry();
IWebSocketConnection connection = webSocketConnectionRegistry.getConnection(application, sessionId, key);
int dataIndex = 0;
while (dataIndex < data.length)
{
try
{
Record record = data[dataIndex++];
String json = String.format(JSON_SKELETON, record.year, record.field, record.value);
if (connection == null || !connection.isOpen())
{
// stop if the web socket connection is closed
return;
}
connection.sendMessage(json);
// sleep for a while to simulate work
TimeUnit.SECONDS.sleep(1);
}
catch (Exception x)
{
x.printStackTrace();
return;
}
}
}
}
/**
* The data that is being sent to the client in JSON format
*/
private static class Record
{
private int year;
private String field;
private int value;
}
}