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 * 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,
 * <http://www.cosylab.com>.
 * 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 gov.aps.jca.test;
import gov.aps.jca.CAException;
import gov.aps.jca.CAStatus;
import gov.aps.jca.Channel;
import gov.aps.jca.Context;
import gov.aps.jca.JCALibrary;
import gov.aps.jca.Monitor;
import gov.aps.jca.dbr.DBR;
import gov.aps.jca.dbr.DBRType;
import gov.aps.jca.dbr.STRING;
import gov.aps.jca.event.GetEvent;
import gov.aps.jca.event.GetListener;
import gov.aps.jca.event.MonitorEvent;
import gov.aps.jca.event.MonitorListener;
 * Simple basic usage test.
 * @author <a href="mailto:matej.sekoranjaATcosylab.com">Matej Sekoranja</a>
 * @version $id$
public class BasicExample {
     * Implementation of get listener.
    private class GetListenerImpl implements GetListener {
        private DBR value = null;
        private CAStatus status = null;
        /**
         * @see gov.aps.jca.event.GetListener#getCompleted(gov.aps.jca.event#GetEvent)
        public synchronized void getCompleted(GetEvent ev) {
            status = ev.getStatus();
            value = ev.getDBR();
            // notify retrival
            this.notifyAll();
        public CAStatus getStatus() {
            return status;
        public DBR getValue() {
            return value;
     * Implementation of monitor listener.
    private static class MonitorListenerImpl implements MonitorListener {
        /**
         * @see gov.aps.jca.event.MonitorListener#monitorChanged(gov.aps.jca.event.MonitorEvent)
        public void monitorChanged(MonitorEvent event) {
            // immediately print info
            if (event.getStatus() == CAStatus.NORMAL)
                event.getDBR().printInfo();
            else
                System.err.println("Monitor error: " + event.getStatus());
     * JCA context.
    private Context context = null;
     * Initialize JCA context.
     * @throws CAException
     *             throws on any failure.
    private void initialize() throws CAException {
        // Get the JCALibrary instance.
        JCALibrary jca = JCALibrary.getInstance();
        // Create a context with default configuration values.
        context = jca.createContext(JCALibrary.CHANNEL_ACCESS_JAVA);
        // Display basic information about the context.
        System.out.println(context.getVersion().getVersionString());
        context.printInfo();
        System.out.println();
     * Destroy JCA context.
    private void destroy() {
        try {
            // Destroy the context, check if never initialized.
            if (context != null)
                context.destroy();
        } catch (Throwable th) {
            th.printStackTrace();
     * @param channelName
    public void execute(String channelName) {
        try {
            // initialize context
            initialize();
            // Create the Channel to connect to the PV.
            Channel channel = context.createChannel(channelName);
            // Send the request and wait 5.0 seconds for the channel to connect
            // to the PV.
            context.pendIO(5.0);
            // If we're here, then everything went fine.
            // Display basic information about the channel.
            channel.printInfo();
            /********************************************************************/
            /*****************************
             * sync get
             *****************************/
            /********************************************************************/
            System.out.println("\n------------------------------------------------\n");
            System.out.println("Sync get:");
            // get request w/o callbacks will wait until flush/pendIO is called
            // (channel default 'type' and 'count' is used)
            DBR dbr = channel.get();
            context.pendIO(3.0);
            dbr.printInfo();
            System.out.println();
            dbr = channel.get(DBRType.STRING, 1);
            context.pendIO(3.0);
            String[] value = ((STRING) dbr).getStringValue();
            System.out.println("Read string value: " + value[0]);
            /********************************************************************/
            /****************************
             * async get
             *****************************/
            /********************************************************************/
            System.out.println("\n------------------------------------------------\n");
            System.out.println("Async get:");
            // get request w/ callbacks are always issued immediately
            // not related to pendIO at all, but require pend_event (to be
            // flushed also)
            GetListenerImpl listener = new GetListenerImpl();
            channel.get(listener);
            synchronized (listener) {
                // flush & get event back
                context.flushIO();
                // wait for response...
                listener.wait(3000);
            if (listener.getStatus() == CAStatus.NORMAL)
                listener.getValue().printInfo();
            else
                System.err.println("Get error: " + listener.getStatus());
            /********************************************************************/
            /***************************** Monitors *****************************/
            /********************************************************************/
            System.out.println("\n------------------------------------------------\n");
            System.out.println("Monitors:");
            System.out.println();
            // Create a monitor
            Monitor monitor = channel.addMonitor(Monitor.VALUE, new MonitorListenerImpl());
            context.flushIO();
            // Sleep for 10 seconds (monitors will be printed out).
            Thread.sleep(10000);
            // Clear the monitor
            monitor.clear();
            System.out.println("\n------------------------------------------------");
            /********************************************************************/
            /********************************************************************/
            /********************************************************************/
            // Disconnect the channel.
            channel.destroy();
            // Flush all pending requests...
            context.flushIO();
            System.out.println("Done.");
        } catch (Throwable th) {
            th.printStackTrace();
        } finally {
            // always finalize
            destroy();
     * Program entry point.
     * @param args
     *            command-line arguments
    public static void main(String[] args) {
        // check command-line arguments
        if (args.length != 1) {
            System.out.println("usage: java " + BasicExample.class.getName() + " <pvname>");
            System.exit(1);
        // execute
        new BasicExample().execute(args[0]);
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