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- /*
- * 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 java.util.HashSet;
- import java.util.Set;
-
- 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.
- * @return a set of connector ids with state changes
- * @throws IOException
- * If the serialization fails.
- */
- public Set<String> write(UI ui, Writer writer) throws IOException {
-
- Collection<ClientConnector> dirtyVisibleConnectors = ui
- .getConnectorTracker().getDirtyVisibleConnectors();
-
- Set<String> writtenConnectors = new HashSet<String>();
- JsonObject sharedStates = Json.createObject();
- for (ClientConnector connector : dirtyVisibleConnectors) {
- // encode and send shared state
- String connectorId = connector.getConnectorId();
- try {
- JsonObject stateJson = connector.encodeState();
-
- if (stateJson != null && stateJson.keys().length != 0) {
- sharedStates.put(connectorId, stateJson);
- writtenConnectors.add(connectorId);
- }
- } catch (JsonException e) {
- throw new PaintException(
- "Failed to serialize shared state for connector "
- + connector.getClass().getName() + " ("
- + connectorId + "): " + e.getMessage(), e);
- }
- }
- writer.write(JsonUtil.stringify(sharedStates));
-
- return writtenConnectors;
- }
- }
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