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Grid BPEL Engine Client developed by Extreme Computing Lab, Indiana University
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/* -*- mode: Java; c-basic-offset: 4; indent-tabs-mode: nil; -*-  //------100-columns-wide------>|*/
/* Copyright (c) 2005 Extreme! Lab, Indiana University. All rights reserved.
 * This software is open source. See the bottom of this file for the licence.
 * $Id: GcInstance.java,v 1.9 2007/01/17 21:42:36 aslom Exp $ */
package org.gpel.client;

import java.net.URI;
import org.gpel.GpelConstants;
import org.gpel.client.http.GcHttpRequest;
import org.gpel.client.http.GcHttpResponse;
import org.gpel.logger.GLogger;
import org.xmlpull.infoset.XmlElement;
import org.xmlpull.infoset.XmlInfosetBuilder;

public class GcInstance extends GcLinksResource {
    private final static GLogger logger = GLogger.getLogger();
    private final static XmlInfosetBuilder builder = GpelConstants.BUILDER;
    public final static String MIME_TYPE = "application/x-gpel-instance+xml";
    public final static String TYPE_NAME = "instance";
    public final static String START_ACTION = "gpel-instance-start";
    public final static String STEP_ACTION = "gpel-instance-step";
    public final static String PAUSE_ACTION = "gpel-instance-pause";
    public final static String RESUME_ACTION = "gpel-instance-resume";
    public final static String STOP_ACTION = "gpel-instance-stop";
    //final String STOP_ACTION = "gpel-instance-resume";
    private final static String PRIORITY_EL = "priority";

    protected GcInstance(GpelClient client, String title, GcLinkFilter filter)
    throws GcException {
        super(client, title, builder.newFragment(GpelConstants.GPEL_NS, TYPE_NAME),
              filter, MIME_TYPE);
        setPriority( GcPriority.SILVER );
    }

    public GcInstance(XmlElement atomRes) {
        super(atomRes);
    }

    public void store() {
        getClient().storeInstance(this);
    }

//    protected GcInstance(GpelClient client, GcXmlWebResource atomRes, GcLinkFilter filter)
//    throws GcException {
//        super(client, atomRes, filter);
//    }

    public URI getInstanceId() throws GcException {
        return getId();
    }

//    public URI getTemplateId() throws GcException {
//        GcWebResource template = getLinkWithRel(GpelConstants.REL_TEMPLATE);
//      return template.getId();
//    }

    public GcPriority getPriority() {
        XmlElement priorityEl = getXmlContent().requiredElement(PRIORITY_EL);
        String s = priorityEl.requiredText();
        return GcPriority.valueOf(s);
    }

    public void setPriority(GcPriority status) {
        XmlElement priority = getXmlContent().element(null, PRIORITY_EL, true);
        priority.setText(status.toString());
    }

    public GcState retrieveCurrentState() {
        GcState oldState = (GcState) getLinkWithRel(GcState.REL);
        if(null == oldState) throw new IllegalStateException("internal");
        String href = oldState.getId().toString();
        String rel = oldState.getRel();
        GcState newState = (GcState) loadXmlResourceLink(href, rel);
        replaceLinkWithRel(newState);
        return newState;
    }


    // extract special link with template relation
    //public URI getTemplateId() throws GcException {
    //    return getId();
    //}

    public GcState start() {
        return executeInstanceAction(START_ACTION);
    }

    public GcState step() {
        return executeInstanceAction(STEP_ACTION);
    }

    public GcState pause() {
        return executeInstanceAction(PAUSE_ACTION);
    }

    public GcState resume() {
        return executeInstanceAction(RESUME_ACTION);
    }

    private GcState executeInstanceAction(String action) {
        URI tloc = getClient().mapIdToLocation(getInstanceId());
        URI loc = URI.create(tloc.toString()+"?action="+action);
        logger.finest("loc="+loc);
        GcHttpRequest.Method httpMethod = GcHttpRequest.Method.POST;

        // TODO: parameters ...
        GcHttpRequest req = new GcHttpRequest(httpMethod, loc, GcUtil.CONTENT_TYPE_ATOM,
                                              builder.newFragment(GcUtil.ATOM_NS, "entry"));

        GcHttpResponse resp = getClient().getTransport().perform(req);

        if (!resp.hasContent()) {
            throw new GcException("expected XML result when POSTing to " + loc);
        }
        //TODO: this needs to be implemented and synced with instance link?!
        GcState state = (GcState) getClient().getResourceFromHttpFactory()
            .createResourceFromHttp(resp, null);
        state.setLocation(resp.getLocation());
        replaceLinkWithRel(state);
        return state;
    }


}