Android Open Source - aBusTripMK Open Street Map Tile Filesystem Provider

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License

The source code is released under:

GNU General Public License

Java Source Code

// Created by plusminus on 21:46:41 - 25.09.2008
package org.andnav.osm.services.util;
/*w  ww .j  a va2  s.  c  o m*/
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import org.andnav.osm.exceptions.EmptyCacheException;
import org.andnav.osm.services.IOpenStreetMapTileProviderCallback;
import org.andnav.osm.views.util.OpenStreetMapRendererInfo;

import android.content.Context;
import android.util.Log;

/**
 * 
 * @author Nicolas Gramlich
 *
 */
public class OpenStreetMapTileFilesystemProvider extends OpenStreetMapAsyncTileProvider {
        // ===========================================================
        // Constants
        // ===========================================================

        final static String DEBUGTAG = "OSM_FS_PROVIDER";

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

        protected final OpenStreetMapTileProviderDataBase mDatabase;
        protected final int mMaxFSCacheByteSize;
        protected int mCurrentFSCacheByteSize;

        /** online provider */
        protected OpenStreetMapTileDownloader mTileDownloader;

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

        /**
         * @param ctx
         * @param aMaxFSCacheByteSize the size of the cached MapTiles will not exceed this size.
         * @param aCache to load fs-tiles to.
         */
        public OpenStreetMapTileFilesystemProvider(final Context ctx, final int aMaxFSCacheByteSize) {
                super(NUMBER_OF_TILE_FILESYSTEM_THREADS, TILE_FILESYSTEM_MAXIMUM_QUEUE_SIZE);
                this.mMaxFSCacheByteSize = aMaxFSCacheByteSize;
                this.mDatabase = new OpenStreetMapTileProviderDataBase(ctx);
                this.mCurrentFSCacheByteSize = this.mDatabase.getCurrentFSCacheByteSize();

                this.mTileDownloader = new OpenStreetMapTileDownloader(this);

                if(DEBUGMODE)
                        Log.d(DEBUGTAG, "Currently used cache-size is: " + this.mCurrentFSCacheByteSize + " of " + this.mMaxFSCacheByteSize + " Bytes");
        }

        // ===========================================================
        // Getter & Setter
        // ===========================================================
        
        public int getCurrentFSCacheByteSize() {
                return this.mCurrentFSCacheByteSize;
        }

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

        @Override
        protected String debugtag() {
                return DEBUGTAG;
        }

        @Override
        protected Runnable getTileLoader(final IOpenStreetMapTileProviderCallback aCallback) {
                return new TileLoader(aCallback);
        };
        
        // ===========================================================
        // Methods
        // ===========================================================

        private String buildPath(final OpenStreetMapTile tile) {
                final OpenStreetMapRendererInfo renderer = OpenStreetMapRendererInfo.values()[tile.rendererID];
                return TILE_PATH_BASE + renderer.name() + "/" + tile.zoomLevel + "/"
                                        + tile.x + "/" + tile.y + renderer.IMAGE_FILENAMEENDING + TILE_PATH_EXTENSION; 
        }
        
        /**
         * Get the file location for the tile.
         * @param tile
         * @return 
         * @throws CantContinueException if the directory containing the file doesn't exist
         * and can't be created
         */
        File getOutputFile(final OpenStreetMapTile tile) throws CantContinueException {
                final File file = new File(buildPath(tile));
                final File parent = file.getParentFile();
                if (!parent.exists() && !parent.mkdirs()) {
                        throw new CantContinueException();
                }
                return file;
        }
        
        void saveFile(final OpenStreetMapTile tile, final File outputFile, final byte[] someData) throws IOException{
                final OutputStream bos = new BufferedOutputStream(new FileOutputStream(outputFile, false), StreamUtils.IO_BUFFER_SIZE);         
                bos.write(someData);
                bos.flush();
                bos.close();

                synchronized (this) {
                        final int bytesGrown = this.mDatabase.addTileOrIncrement(tile, someData.length);
                        this.mCurrentFSCacheByteSize += bytesGrown;

                        if(DEBUGMODE)
                                Log.d(DEBUGTAG, "FSCache Size is now: " + this.mCurrentFSCacheByteSize + " Bytes");

                        /* If Cache is full... */
                        try {

                                if(this.mCurrentFSCacheByteSize > this.mMaxFSCacheByteSize){
                                        if(DEBUGMODE)
                                                Log.d(DEBUGTAG, "Freeing FS cache...");
                                        this.mCurrentFSCacheByteSize -= this.mDatabase.deleteOldest((int)(this.mMaxFSCacheByteSize * 0.05f)); // Free 5% of cache
                                }
                        } catch (EmptyCacheException e) {
                                if(DEBUGMODE)
                                        Log.d(DEBUGTAG, "Cache empty", e);
                        }
                }
        }

        public void clearCurrentFSCache(){
                cutCurrentFSCacheBy(Integer.MAX_VALUE); // Delete all
        }
        
        public void cutCurrentFSCacheBy(final int bytesToCut){
                try {
                        this.mDatabase.deleteOldest(Integer.MAX_VALUE); // Delete all
                        this.mCurrentFSCacheByteSize = 0;
                } catch (EmptyCacheException e) {
                        if(DEBUGMODE)
                                Log.d(DEBUGTAG, "Cache empty", e);
                }
        }

        // ===========================================================
        // Inner and Anonymous Classes
        // ===========================================================

        private class TileLoader extends OpenStreetMapAsyncTileProvider.TileLoader {

                public TileLoader(final IOpenStreetMapTileProviderCallback aCallback) {
                        super(aCallback);
                }

                @Override
                public String loadTile(final OpenStreetMapTile aTile) throws CantContinueException {
                        mDatabase.incrementUse(aTile);
                        final File tileFile = getOutputFile(aTile);
                        try {
                                if (tileFile.exists()) {
                                        if (DEBUGMODE)
                                                Log.d(DEBUGTAG, "Loaded tile: " + aTile);
                                        return tileFile.getPath();
                                } else {
                                        if (DEBUGMODE)
                                                Log.d(DEBUGTAG, "Tile not exist, request for download: " + aTile);
                                        mTileDownloader.loadMapTileAsync(aTile, mCallback);
                                        return null;
                                }
                        } catch (final Throwable e) {
                                Log.e(DEBUGTAG, "Error loading tile", e);
                                return null;
                        }
                }
        }
}

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