org.webpda.server.core.servermessage.PVEventMessage.java Source code

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Here is the source code for org.webpda.server.core.servermessage.PVEventMessage.java

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/*******************************************************************************
 * Copyright (c) 2013 Oak Ridge National Laboratory.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 ******************************************************************************/
package org.webpda.server.core.servermessage;

import java.io.ByteArrayOutputStream;
import java.util.logging.Level;

import org.webpda.server.core.Constants;
import org.webpda.server.core.util.JsonUtil;
import org.webpda.server.core.util.LoggerUtil;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;

/**A server message that represents a PV related event.
 * @author Xihui Chen
 *
 */
public class PVEventMessage extends AbstractTextMessage {

    private static final String DATA = "d";

    private static final String EVENT = "e";

    private static final String PVID = "pv";

    //pv id.
    private int id;

    private PVEventType evt;

    private Object data;

    private boolean isRawJson;

    public PVEventMessage(int pvId, PVEventType eventType, Object data, boolean isRawJson) {
        this.id = pvId;
        this.evt = eventType;
        this.data = data;
        this.isRawJson = isRawJson;
    }

    @Override
    public String createJson() throws JsonProcessingException {
        try {
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            JsonGenerator jg = JsonUtil.jsonFactory.createGenerator(outputStream);
            jg.writeStartObject();
            jg.writeNumberField(PVID, id);
            jg.writeStringField(EVENT, evt.name());
            jg.writeFieldName(DATA);
            if (isRawJson)
                jg.writeRaw(":" + data);
            else
                jg.writeObject(data);
            jg.writeEndObject();
            jg.close();
            String s = outputStream.toString(Constants.CHARSET);
            //         System.out.println(s.length() + s);
            outputStream.close();
            return s;
        } catch (Exception e) {
            LoggerUtil.getLogger().log(Level.SEVERE, "Failed to create json.", e);
        }

        return null;
    }

}