/*
* Copyright 2000-2014 Vaadin Ltd.
*
* Licensed 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.vaadin.server.communication;
import java.io.IOException;
import java.io.Serializable;
import java.io.Writer;
import java.util.Collection;
import com.vaadin.server.ClientConnector;
import com.vaadin.server.PaintException;
import com.vaadin.shared.communication.SharedState;
import com.vaadin.ui.UI;
import elemental.json.Json;
import elemental.json.JsonException;
import elemental.json.JsonObject;
import elemental.json.impl.JsonUtil;
/**
* Serializes {@link SharedState shared state} changes to JSON.
*
* @author Vaadin Ltd
* @since 7.1
*/
public class SharedStateWriter implements Serializable {
/**
* Writes a JSON object containing the pending state changes of the dirty
* connectors of the given UI.
*
* @param ui
* The UI whose state changes should be written.
* @param writer
* The writer to use.
* @throws IOException
* If the serialization fails.
*/
public void write(UI ui, Writer writer) throws IOException {
Collection<ClientConnector> dirtyVisibleConnectors = ui
.getConnectorTracker().getDirtyVisibleConnectors();
JsonObject sharedStates = Json.createObject();
for (ClientConnector connector : dirtyVisibleConnectors) {
// encode and send shared state
try {
JsonObject stateJson = connector.encodeState();
if (stateJson != null && stateJson.keys().length != 0) {
sharedStates.put(connector.getConnectorId(), stateJson);
}
} catch (JsonException e) {
throw new PaintException(
"Failed to serialize shared state for connector "
+ connector.getClass().getName() + " ("
+ connector.getConnectorId() + "): "
+ e.getMessage(), e);
}
}
writer.write(JsonUtil.stringify(sharedStates));
}
}