com.cosylab.epics.caj.impl.requests.ReadNotifyRequest Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jca Show documentation

JCA is an EPICS Channel Access library for Java. For more information concerning EPICS or Channel Access please refer to the <a href="http://www.aps.anl.gov/epics">EPICS Web pages</a> or read the <a href="http://www.aps.anl.gov/epics/base/R3-14/8-docs/CAref.html">Channel Access manual (3.14)</a>. <p>This module also includes CAJ, A 100% pure Java implementation of the EPICS Channel Access library.</p>

There is a newer version: 2.4.10

Show newest version

/*
 * Copyright (c) 2004 by Cosylab
 *
 * The full license specifying the redistribution, modification, usage and other
 * rights and obligations is included with the distribution of this project in
 * the file "LICENSE-CAJ". If the license is not included visit Cosylab web site,
 * .
 *
 * THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND, NOT EVEN THE
 * IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE, ASSUMES
 * _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE RESULTING FROM THE USE, MODIFICATION,
 * OR REDISTRIBUTION OF THIS SOFTWARE.
 */

package com.cosylab.epics.caj.impl.requests;

import gov.aps.jca.CAStatus;
import gov.aps.jca.dbr.DBR;
import gov.aps.jca.dbr.DBRType;
import gov.aps.jca.event.ContextExceptionEvent;
import gov.aps.jca.event.GetEvent;
import gov.aps.jca.event.GetListener;

import java.io.IOException;
import java.nio.ByteBuffer;

import com.cosylab.epics.caj.CAJChannel;
import com.cosylab.epics.caj.CAJContext;
import com.cosylab.epics.caj.impl.DBRDecoder;
import com.cosylab.epics.caj.impl.NotifyResponseRequest;
import com.cosylab.epics.caj.impl.Transport;

/**
 * CA read notify.
 * @author Matej Sekoranja
 * @version $id$
 */
public class ReadNotifyRequest extends AbstractCARequest implements NotifyResponseRequest {

	/**
	 * Context.
	 */
	protected CAJContext context;

	/**
	 * I/O ID given by the context when registered.
	 */
	protected int ioid;

	/**
	 * Channel server ID.
	 */
	protected int sid;

	/**
	 * Response callback listener.
	 */
	protected GetListener callback;

	/**
	 * DBR to be set (sync. request).
	 */
	protected DBR dbr;

	/**
	 * Sync. request flag.
	 */
	protected boolean sync;

	/**
	 * IO sequence number.
	 */
	protected int sequenceNumberIO;

	/**
	 * Channel.
	 */
	protected CAJChannel channel;

	/**
	 * Requested data type.
	 */
	protected int requestedDataType;
	
	/**
	 * Requested data count.
	 */
	protected int requestedDataCount;

	/**
	 * Requested data count.
	 */
	protected boolean prohibitIOCancel = false;

	/**
	 * @param channel 
	 * @param callback
	 * @param dbr
	 * @param transport
	 * @param sid
	 * @param dataType
	 * @param dataCount
	 */
	public ReadNotifyRequest(CAJChannel channel, GetListener callback, DBR dbr,
							 Transport transport, int sid, int dataType, int dataCount) {
		super(transport);

		this.channel = channel;
		this.callback = callback;
		this.dbr = dbr; 
		this.sid = sid;
		this.requestedDataType = dataType;
		
		if (dataCount == 0 && channel.getTransport().getMinorRevision() < 13)
			dataCount = channel.getElementCount();

		this.requestedDataCount = dataCount;
		
		sync = (dbr != null); 
		// TODO not clean
		context = (CAJContext)transport.getContext(); // or channel.getContext()
		ioid = context.registerResponseRequest(this);
		channel.registerResponseRequest(this);
		
	    requestMessage = insertCAHeader(transport, null,
	            						(short)15, 0, (short)dataType, dataCount,
	            						sid, ioid);
	}

	/**
	 * @see com.cosylab.epics.caj.impl.ResponseRequest#getIOID()
	 */
	public int getIOID() {
		return ioid;
	}

	/**
	 * @see com.cosylab.epics.caj.impl.NotifyResponseRequest#response(int, short, int, java.nio.ByteBuffer)
	 */
	public void response(
		int status,
		short dataType,
		int dataCount,
		ByteBuffer dataPayloadBuffer) {

		try
		{			
			// HexDump.hexDump(description, dataPayloadBuffer.array(), dataPayloadBuffer.limit());
	
			CAStatus caStatus = CAStatus.forStatusCode(status);
			if (caStatus == CAStatus.NORMAL)
				dbr = DBRDecoder.getDBR(dbr, dataType, dataCount, dataPayloadBuffer);
			else
				// do not decrement pending IO, if non-callback read is used
				prohibitIOCancel = true;
			
			// notify
			if (callback != null )
				context.getEventDispatcher().dispatch(
				        new GetEvent(channel, dbr, caStatus),
						callback
					);
		}
		finally
		{
			// allways cancel request
			cancel();
		}
	}

	/**
	 * If sync. request (i.e. w/o callback), additionally increment context pending requests.
	 * @see com.cosylab.epics.caj.impl.Request#submit()
	 */
	public void submit() throws IOException {
		super.submit();
		if (sync)
			sequenceNumberIO = context.incrementPendingRequests();
	}

	/**
	 * @see com.cosylab.epics.caj.impl.ResponseRequest#cancel()
	 */
	public void cancel() {
		// unregister response request
		boolean alreadyCanceled = (context.unregisterResponseRequest(this) == null);
		if (!alreadyCanceled && sync && !prohibitIOCancel)
			context.decrementPendingRequests(sequenceNumberIO);
		channel.unregisterResponseRequest(this);
	}

	/**
	 * @see com.cosylab.epics.caj.impl.ResponseRequest#timeout()
	 */
	public void timeout() {

		// do not decrement pending IO, if non-callback read is used
		prohibitIOCancel = true;

		cancel();
		// ... and notify
		if (callback != null)
			context.getEventDispatcher().dispatch(
			        new GetEvent(channel, null, CAStatus.TIMEOUT),
					callback
				);
	}

	/**
	 * @see com.cosylab.epics.caj.impl.ResponseRequest#exception(int, java.lang.String)
	 */
	public void exception(int errorCode, String errorMessage) {
		
		// do not decrement pending IO, if non-callback read is used
		prohibitIOCancel = true;

		cancel();

		// TODO no status is dispatched 
		if (errorMessage == null)
		{
			CAStatus status = CAStatus.forStatusCode(errorCode);
			if (status != null)
				errorMessage = status.getMessage();
		}
		ContextExceptionEvent cee = new ContextExceptionEvent(context, channel,
				DBRType.forValue(requestedDataType), requestedDataCount, dbr, errorMessage);
		context.notifyException(cee);

		/*
		// ... and notify
		if (callback != null)
		{
			CAStatus status = CAStatus.forValue(errorCode);
			if (status == null)
			    status = CAStatus.GETFAIL;

			context.getEventDispatcher().dispatch(
			        new GetEvent(channel, null, status),
					callback
				);
		}
		*/
		
	}

}