OpenStreetMapTileProvider.java

/* 
This file is part of OpenSatNav.

    OpenSatNav 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 3 of the License, or
    (at your option) any later version.

    OpenSatNav 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 OpenSatNav.  If not, see <http://www.gnu.org/licenses/>.
 */
// Created by plusminus on 21:46:22 - 25.09.2008
package org.andnav.osm.views.util;

import org.andnav.osm.util.constants.OpenStreetMapConstants;
import org.andnav.osm.views.util.constants.OpenStreetMapViewConstants;
import org.opensatnav.R;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;
import android.preference.PreferenceManager;
import android.util.Log;

/**
 * 
 * @author Nicolas Gramlich
 * 
 */
public class OpenStreetMapTileProvider implements OpenStreetMapConstants,
		OpenStreetMapViewConstants, OnSharedPreferenceChangeListener {
	// ===========================================================
	// Constants
	// ===========================================================

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

	protected final Bitmap mLoadingMapTile;
	protected Context mCtx;
	protected OpenStreetMapTileCache mTileCache;
	protected OpenStreetMapTileFilesystemProvider mFSTileProvider;
	protected OpenStreetMapTileDownloader mTileDownloader;
	private Handler mLoadCallbackHandler = new LoadCallbackHandler();
	private Handler mDownloadFinishedListenerHander;

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

	public OpenStreetMapTileProvider(final Context ctx,
			final Handler aDownloadFinishedListener) {
		this.mCtx = ctx;
		this.mLoadingMapTile = BitmapFactory.decodeResource(ctx.getResources(),
				R.drawable.maptile_loading);
		this.mTileCache = new OpenStreetMapTileCache();
		SharedPreferences settings = PreferenceManager
				.getDefaultSharedPreferences(ctx);
		settings.registerOnSharedPreferenceChangeListener(this);

		int MbsAllocated = settings.getInt("maxSdCardUsageMb", 64);

		this.mFSTileProvider = new OpenStreetMapTileFilesystemProvider(ctx,
				MbsAllocated * 1024 * 1024, this.mTileCache);
		this.mTileDownloader = new OpenStreetMapTileDownloader(ctx,
				this.mFSTileProvider, this.mTileCache);
		this.mFSTileProvider.setTileDownloader(mTileDownloader);
		this.mDownloadFinishedListenerHander = aDownloadFinishedListener;
	}

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

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

	// ===========================================================
	// Methods
	// ===========================================================

	public Bitmap getMapTile(final String aTileURLString) {
		Bitmap ret = this.mTileCache.getMapTile(aTileURLString);
		if (ret != null) {
			if (DEBUGMODE)
				Log.i(DEBUGTAG, "MapTileCache succeeded for: " + aTileURLString);
		} else {
			if (DEBUGMODE)
				Log.i(DEBUGTAG, "Cache failed, trying from FS for " + aTileURLString);
			try {
				this.mFSTileProvider.loadMapTileToMemCacheAsync(aTileURLString,
						this.mLoadCallbackHandler);
				// if no file is found, an exception will be thrown by the line above 
				// and ret will stay null, which will start an async download below after the catch block
				ret = this.mLoadingMapTile;
			} catch (Exception e) {
				if (DEBUGMODE)
					Log.d(DEBUGTAG, "Error("
							+ e.getClass().getSimpleName()
							+ ") loading MapTile from Filesystem: "
							+ OpenStreetMapTileNameFormatter
									.format(aTileURLString));
			}
			if (ret == null) { /*
								 * FS did not contain the MapTile, we need to
								 * download it asynchronous.
								 */
				if (DEBUGMODE)
					Log.i(DEBUGTAG, "Requesting Maptile for download.");
				ret = this.mLoadingMapTile;

				this.mTileDownloader.requestMapTileAsync(aTileURLString,
						this.mLoadCallbackHandler, null);
			}
		}
		return ret;
	}

	// ===========================================================
	// Inner and Anonymous Classes
	// ===========================================================
	private class LoadCallbackHandler extends Handler {
		@Override
		public void handleMessage(final Message msg) {
			final int what = msg.what;			
			switch (what) {
			case OpenStreetMapTileDownloader.MAPTILEDOWNLOADER_SUCCESS_ID:
				OpenStreetMapTileProvider.this.mDownloadFinishedListenerHander
						.sendEmptyMessage(OpenStreetMapTileDownloader.MAPTILEDOWNLOADER_SUCCESS_ID);
				if (DEBUGMODE)
					Log.i(DEBUGTAG, "MapTile download success.");
				break;
			case OpenStreetMapTileDownloader.MAPTILEDOWNLOADER_FAIL_ID:
				if (DEBUGMODE)
					Log.e(DEBUGTAG, "MapTile download error.");					
				break;

			case OpenStreetMapTileFilesystemProvider.MAPTILEFSLOADER_SUCCESS_ID:
				OpenStreetMapTileProvider.this.mDownloadFinishedListenerHander
						.sendEmptyMessage(OpenStreetMapTileFilesystemProvider.MAPTILEFSLOADER_SUCCESS_ID);
				if (DEBUGMODE)
					Log.i(DEBUGTAG, "MapTile fs->cache success.");
				break;
			case OpenStreetMapTileFilesystemProvider.MAPTILEFSLOADER_FAIL_ID:
				if (DEBUGMODE)
					Log.e(DEBUGTAG, "MapTile download error.");
				break;
			}
		}
	}

	public void preCacheTile(String aTileURLString) {
		getMapTile(aTileURLString);
	}

	public void ensureMemoryCacheSize(int newSize) {
		mTileCache.ensureCacheSize(newSize);
	}

	@Override
	public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
			String key) {
		if (key.contentEquals("sdMaxUsageMb")) {
			int newSize = sharedPreferences.getInt("sdMaxUsageMb", 32);
			mFSTileProvider.setCurrentFSCacheByteSize(newSize*1024*1024);
		}
		else if (key.contentEquals("clear_cache")) {
			mFSTileProvider.clearCurrentFSCache();
		}

	}

}