MapTileDownloader.java

// Created by plusminus on 21:31:36 - 25.09.2008
package de.blau.android.services.util;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.concurrent.Executors;

import android.content.Context;
import android.os.RemoteException;
import android.util.Log;
import de.blau.android.App;
import de.blau.android.prefs.Preferences;
import de.blau.android.resources.TileLayerServer;
import de.blau.android.services.IMapTileProviderCallback;
import de.blau.android.util.NetworkStatus;

/**
 * The OpenStreetMapTileDownloader loads tiles from a server and passes them to
 * a OpenStreetMapTileFilesystemProvider.<br/>
 * This class was taken from OpenStreetMapViewer (original package org.andnav.osm) in 2010-06
 * by Marcus Wolschon to be integrated into the de.blau.androin
 * OSMEditor. 
 * @author Nicolas Gramlich
 * @author Marcus Wolschon <Marcus@Wolschon.biz
 * @author Manuel Stahl
 *
 */
public class MapTileDownloader extends MapAsyncTileProvider {
	// ===========================================================
	// Constants
	// ===========================================================

	private static final String DEBUGTAG = "OSM_DOWNLOADER";

	// ===========================================================
	// Fields
	// ===========================================================

	private final Context mCtx;
	private final MapTileFilesystemProvider mMapTileFSProvider;

	// ===========================================================
	// Constructors
	// ===========================================================

	public MapTileDownloader(final Context ctx, final MapTileFilesystemProvider aMapTileFSProvider){
		mCtx = ctx;
		mMapTileFSProvider = aMapTileFSProvider;
		mThreadPool = Executors.newFixedThreadPool((new Preferences(ctx)).getMaxTileDownloadThreads());
	}

	// ===========================================================
	// Getter & Setter
	// ===========================================================

	// ===========================================================
	// Methods from SuperClass/Interfaces
	// ===========================================================

	@Override
	protected Runnable getTileLoader(MapTile aTile, IMapTileProviderCallback aCallback) {
		return new TileLoader(aTile, aCallback);
	}
	
	// ===========================================================
	// Methodsorg.andnav.osm.services
	// ===========================================================

	private String buildURL(final MapTile tile) {
		TileLayerServer renderer = TileLayerServer.get(mCtx, tile.rendererID, false);
		// Log.d("OpenStreetMapTileDownloader","metadata loaded "+ renderer.isMetadataLoaded() + " " + renderer.getTileURLString(tile));
		return renderer.isMetadataLoaded() ? renderer.getTileURLString(tile) : "";
	}

	// ===========================================================
	// Inner and Anonymous Classes
	// ===========================================================
	
	private class TileLoader extends MapAsyncTileProvider.TileLoader {
		
		public TileLoader(final MapTile aTile, final IMapTileProviderCallback aCallback) {
			super(aTile, aCallback);
		}
		
		@Override
		public void run() {
			
			if (!NetworkStatus.isConnected(mCtx)) { // fail immediately
				try {
					Log.e(DEBUGTAG, "No network");
					mCallback.mapTileFailed(mTile.rendererID, mTile.zoomLevel, mTile.x, mTile.y,NONETWORK);
				} catch (RemoteException re) {
					Log.e(DEBUGTAG, "Error calling mapTileLoaded for MapTile. Exception: " + re);
				}
				return;
			}
			
			InputStream in = null;
			OutputStream out = null;
			
			String tileURLString = buildURL(mTile);
			try {
				if (tileURLString.length() > 0) {
					if(Log.isLoggable(DEBUGTAG, Log.DEBUG)) {
						Log.d(DEBUGTAG, "Downloading Maptile from url: " + tileURLString);
					}
					URLConnection conn = new URL(tileURLString).openConnection();
					conn.setRequestProperty("User-Agent", App.userAgent);
					if ("BING".equals(mTile.rendererID)) {
						// this is fairly expensive so only do it is we are actually querying bing
						if ("no-tile".equals(conn.getHeaderField("X-VE-Tile-Info"))) {
							// handle special Bing header that indicates no tile is available
							throw new FileNotFoundException("tile not available");
						}
					}
					in = new BufferedInputStream(conn.getInputStream(), StreamUtils.IO_BUFFER_SIZE);
					
					final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
					out = new BufferedOutputStream(dataStream, StreamUtils.IO_BUFFER_SIZE);
					StreamUtils.copy(in, out);
					out.flush();
					
					final byte[] data = dataStream.toByteArray();
					
					if (data.length == 0) {
						throw new IOException("no tile data");
					}
					mCallback.mapTileLoaded(mTile.rendererID, mTile.zoomLevel, mTile.x, mTile.y, data);
					
					MapTileDownloader.this.mMapTileFSProvider.saveFile(mTile, data);
					if(Log.isLoggable(DEBUGTAG, Log.DEBUG)) {
						Log.d(DEBUGTAG, "Maptile " + tileURLString + " saved");
					}
				}
			} catch (IOException ioe) {
				try {
					int reason = ioe instanceof FileNotFoundException ? DOESNOTEXIST : IOERR;
					if (reason == DOESNOTEXIST) {
						MapTileDownloader.this.mMapTileFSProvider.markAsInvalid(mTile);
					}
					mCallback.mapTileFailed(mTile.rendererID, mTile.zoomLevel, mTile.x, mTile.y,reason);
				} catch (RemoteException re) {
					Log.e(DEBUGTAG, "Error calling mCallback for MapTile. Exception: " + ioe.getClass().getSimpleName() + " further mapTileFailed failed " + re, ioe);
				} catch (NullPointerException npe) {
					Log.e(DEBUGTAG, "Error calling mCallback for MapTile. Exception: " + ioe.getClass().getSimpleName() + " further mapTileFailed failed " + npe, ioe);
				} catch (IOException ioe2) {
					Log.e(DEBUGTAG, "Error calling mCallback for MapTile. Exception: " + ioe.getClass().getSimpleName() + " further mapTileFailed failed " + ioe2, ioe);
				}
				if (!(ioe instanceof FileNotFoundException)) {
					// FileNotFound is an expected exception, any other IOException should be logged 
					if(Log.isLoggable(DEBUGTAG, Log.ERROR)) {
						Log.e(DEBUGTAG, "Error Downloading MapTile. Exception: " + ioe.getClass().getSimpleName() + " " + tileURLString, ioe);
					}
				}
				/* TODO What to do when downloading tile caused an error?
				 * Also remove it from the mPending?
				 * Doing not blocks it for the whole existence of this TileDownloader.
				 * -> we remove it and the application has to re-request it.
				 */
			} catch (RemoteException re) {
				Log.e(DEBUGTAG, "Error calling mapTileLoaded for MapTile. Exception: " + re);
			} catch (NullPointerException npe) {
				Log.e(DEBUGTAG, "Error calling mapTileLoaded for MapTile. Exception: " + npe);
			} finally {
				StreamUtils.closeStream(in);
				StreamUtils.closeStream(out);
				finished();
			}
		}
	}
}