org.daxplore.presenter.client.model.StatDataServerModel.java Source code

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Here is the source code for org.daxplore.presenter.client.model.StatDataServerModel.java

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/**
 *  This file is part of Daxplore Presenter.
 *
 *  Daxplore Presenter is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2.1 of the License, or
 *  (at your option) any later version.
 *
 *  Daxplore Presenter is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Daxplore Presenter.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.daxplore.presenter.client.model;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

import org.daxplore.presenter.client.event.QueryReadyEvent;
import org.daxplore.presenter.client.json.shared.ChartDataParserClient;
import org.daxplore.presenter.shared.PrefixProperties;
import org.daxplore.presenter.shared.QueryDefinition;

import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;
import com.google.gwt.http.client.URL;
import com.google.gwt.user.client.Window;
import com.google.inject.Inject;
import com.google.web.bindery.event.shared.EventBus;

public class StatDataServerModel {

    private EventBus eventBus;

    private Map<String, ChartDataParserClient> queryDataCache = new HashMap<String, ChartDataParserClient>();

    private String href;

    private QueryDefinition currentQuery;

    @Inject
    public StatDataServerModel(EventBus eventBus, PrefixProperties prefixProperties) {
        this.eventBus = eventBus;

        href = Window.Location.getProtocol() + "//" + Window.Location.getHost() + "/getStats?prefix="
                + prefixProperties.getPrefix() + "&";
    }

    public void makeRequest(QueryDefinition queryDefinition) {
        currentQuery = queryDefinition;
        String requestString = getRequestString(queryDefinition);
        if (queryDataCache.containsKey(requestString)) {
            onDataLoaded();
        } else {
            String url = href + requestString;
            RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(url));
            builder.setTimeoutMillis(5000); //TODO better timeout handling
            try {
                builder.sendRequest(null, new StatsRequest(queryDefinition));
            } catch (RequestException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    /**
     * Called when requested data is available
     */
    private void onDataLoaded() {
        String requestString = getRequestString(currentQuery);
        // Make sure the newly loaded doesn't belong to an old request
        if (currentQuery != null && queryDataCache.containsKey(requestString)) {
            ChartDataParserClient data = queryDataCache.get(requestString);
            eventBus.fireEvent(new QueryReadyEvent(currentQuery, data));
            currentQuery = null;
        }
    }

    private static String getRequestString(QueryDefinition queryDefinition) {
        return "q=" + queryDefinition.getAsString();
    }

    /**
     * Internal class for requesting data from server.
     */
    private class StatsRequest implements RequestCallback {
        private QueryDefinition queryDefinition;

        private StatsRequest(QueryDefinition queryDefinition) {
            this.queryDefinition = queryDefinition;
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public void onResponseReceived(Request request, Response response) {
            if (response.getStatusCode() == HttpServletResponse.SC_OK) {
                System.out.println("Server Data: " + response.getText());
                ChartDataParserClient data = ChartDataParserClient.parseJson(response.getText());
                String requestString = getRequestString(queryDefinition);
                if (!queryDataCache.containsKey(requestString)) {
                    queryDataCache.put(requestString, data);
                }
                onDataLoaded();
            } else {
                // TODO Handle the error.
                System.out.println("StatsRequest bad response status: " + response.getStatusText());
            }
        }

        /**
         * {@inheritDoc}
         */
        @Override
        public void onError(Request request, Throwable exception) {
            // TODO Couldn't connect to server (could be timeout, SOP violation, etc.)
            System.out.println("StatsRequest onError: " + exception.getMessage());
            exception.printStackTrace();
        }
    }
}