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OpenGL vector map library written in Java - running on Android, iOS, Desktop and within the browser.
There is a newer version: 0.20.0
/*
 * Copyright 2014 Hannes Janetzek
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see .
 */
package org.oscim.tiling.source;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.jsonp.client.JsonpRequest;
import com.google.gwt.jsonp.client.JsonpRequestBuilder;
import com.google.gwt.user.client.rpc.AsyncCallback;

import org.oscim.layers.tile.MapTile;
import org.oscim.layers.tile.MapTile.State;
import org.oscim.tiling.ITileDataSink;
import org.oscim.tiling.ITileDataSource;
import org.oscim.tiling.source.geojson.GeoJsonTileDecoder;
import org.oscim.tiling.source.geojson.GeoJsonTileSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.InputStream;

import static org.oscim.tiling.QueryResult.FAILED;
import static org.oscim.tiling.QueryResult.SUCCESS;

public class JsonTileDataSource implements ITileDataSource {
    static final Logger log = LoggerFactory.getLogger(JsonTileDataSource.class);

    protected final GeoJsonTileDecoder mTileDecoder;
    protected final UrlTileSource mTileSource;

    public JsonTileDataSource(GeoJsonTileSource tileSource) {
        mTileSource = tileSource;
        mTileDecoder = new GeoJsonTileDecoder(tileSource);
    }

    UrlTileSource getTileSource() {
        return mTileSource;
    }

    private ITileDataSink mSink;
    private MapTile mTile;

    @Override
    public void query(MapTile tile, ITileDataSink sink) {
        mTile = tile;
        mSink = sink;

        try {
            doGet(mTileSource.getTileUrl(tile));
        } catch (Exception e) {
            e.printStackTrace();
            sink.completed(FAILED);
        }
    }

    public void process(InputStream is) {
    }

    boolean mFinished;

    @Override
    public void dispose() {
        mFinished = true;
    }

    @Override
    public void cancel() {
        mFinished = true;
    }

    JsonpRequest mRequestHandle;

    void doGet(final String url) {
        JsonpRequestBuilder builder = new JsonpRequestBuilder();
        //builder.setCallbackParam("json_callback");

        mRequestHandle = builder.requestObject(url, new AsyncCallback() {
            @Override
            public void onFailure(Throwable caught) {

                mSink.completed(FAILED);
                log.debug("fail! {} {}", mRequestHandle, caught.getMessage());
                //mRequestHandle.cancel();
            }

            @Override
            public void onSuccess(JavaScriptObject jso) {
                if (mTile.state(State.NONE)) {
                    log.debug("tile cleared {}", url);
                    mSink.completed(FAILED);
                    return;
                }

                if (jso == null) {
                    log.debug("Couldn't retrieve JSON for {}", url);
                    mSink.completed(FAILED);
                    return;
                }

                try {
                    if (mTileDecoder.decode(mTile, mSink, jso)) {
                        mSink.completed(SUCCESS);
                        return;
                    }
                } catch (Exception e) {
                    log.debug("Couldn't retrieve JSON for {} {}" + url, e);
                    // FIXME need to check where it might be thrown
                    mSink.completed(FAILED);
                }
            }
        });
    }
}