PVStatusAction.java

/*******************************************************************************
 * Copyright (c) 2011 The Board of Trustees of the Leland Stanford Junior University
 * as Operator of the SLAC National Accelerator Laboratory.
 * Copyright (c) 2011 Brookhaven National Laboratory.
 * EPICS archiver appliance is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution.
 *******************************************************************************/
package org.epics.archiverappliance.engine.bpl;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.LinkedList;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.epics.archiverappliance.common.BPLAction;
import org.epics.archiverappliance.config.ConfigService;
import org.epics.archiverappliance.config.PVTypeInfo;
import org.epics.archiverappliance.engine.ArchiveEngine;
import org.epics.archiverappliance.engine.epics.EngineChannelStatus;
import org.epics.archiverappliance.engine.pv.PVMetrics;
import org.epics.archiverappliance.utils.ui.MimeTypeConstants;

/**
 * BPL for getting the status of a PV.
 * @author mshankar
 *
 */
public class PVStatusAction implements BPLAction {
	private static Logger logger = Logger.getLogger(PVStatusAction.class.getName());

	@Override
	public void execute(HttpServletRequest req, HttpServletResponse resp, ConfigService configService) throws IOException {
		String pvNamesStr = req.getParameter("pv");
		if(pvNamesStr == null || pvNamesStr.equals("")) {
			resp.sendError(HttpServletResponse.SC_BAD_REQUEST);
			return;
		}
		
		String[] pvNames = pvNamesStr.split(",");
		LinkedList<EngineChannelStatus> statuses = new LinkedList<EngineChannelStatus>();
		
		for(String pvName : pvNames) { 
			try {
				PVTypeInfo typeInfoForPV = configService.getTypeInfoForPV(pvName);
				if(typeInfoForPV == null) {
					logger.error("Could not find pv type info for PV " + pvName);
					continue;
				}
				PVMetrics metricsforPV = ArchiveEngine.getMetricsforPV(pvName,configService);
				if(metricsforPV != null) {
					statuses.add(new EngineChannelStatus(metricsforPV));
				} else {
					logger.warn("Could not determine metrics for PV " + pvName);
					continue;
				}
			} catch(Exception ex) {
				throw new IOException(ex);
			}
		}
			
		resp.setContentType(MimeTypeConstants.APPLICATION_JSON);
		boolean first = true;
		try (PrintWriter out = resp.getWriter()) {
			out.println("[");
			for(EngineChannelStatus status : statuses) { 
				if(first) { 
					first = false;
				} else { 
					out.println(",");
				}
				out.print(status.toJSONString());
			}
			out.println();
			out.println("]");
		}
	}
}