Android Open Source - android-open-street-map In Db Tile Loader

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License

The source code is released under:

Apache License

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Java Source Code

package com.android.lib.map.osm;
// w ww . j a  v a2 s. co m
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;

import com.android.lib.map.osm.models.MapTile;

import android.graphics.Bitmap;

public class InDbTileLoader extends Thread {
  
  private static final int STACK_DB_QUERY_LIMIT = 16;
  private static final int MAX_TILES_REQUEST_PER_SQL_QUERY = 16;
  
  private Stack<Tile> mTiles;
  private IDbTileLoaderListener mDbTileLoaderListener;

  
  public InDbTileLoader(IDbTileLoaderListener dbTileLoaderListener) {
    mTiles = new Stack<Tile>();
    mDbTileLoaderListener = dbTileLoaderListener;
    start();
  }

  public void queue(Tile tile) {

    if (!stackHasTile(tile)) {

      synchronized (this) {
        if (mTiles.size() >= STACK_DB_QUERY_LIMIT)
          mTiles.remove(mTiles.lastElement());

        mTiles.push(tile);
        //Log.i("InDbTileLoader", "InDbTileLoader ADD size=" + mTiles.size());

        this.notify();
      }
    }
  }
  
  @Override
  public void run() {
    
    List<Tile> tiles = new ArrayList<Tile>();

    while(true) {
      
      int i = 0;
      tiles.clear();
      
      if (stackSize() > 0) {
        while (stackSize() > 0 && i < MAX_TILES_REQUEST_PER_SQL_QUERY) {
          tiles.add(stackPop());
          i++;
        }
      }
      
      if (tiles.size() > 0) {

        List<Tile> tilesNotLoaded = new ArrayList<Tile>();
        Map<Tile, Bitmap> tilesLoaded = new HashMap<Tile, Bitmap>();
        Map<Tile, Bitmap> map = MapTile.getTiles(tiles);
        if (map != null) {
          for (Map.Entry<Tile, Bitmap> entry : map.entrySet()) {
            Tile tile = entry.getKey();
            Bitmap bitmap = entry.getValue();
            if (bitmap == null)
              tilesNotLoaded.add(tile);
            else
              tilesLoaded.put(tile, bitmap);
          }
          
          if (tilesLoaded.size() > 0)
            mDbTileLoaderListener.onTilesLoadedFromDb(tilesLoaded);
          if (tilesNotLoaded.size() > 0)
            mDbTileLoaderListener.onTilesNotLoadedFromDb(tilesNotLoaded);
        }
      }
      
      try {
        synchronized (this) {
          if (mTiles.size() == 0) {
            this.wait();
          }
        }
        //Thread.sleep(50);
      } 
      catch (InterruptedException e) {
        break;
      }
    }
  }
  
//  @Override
//  public void run() {
//    Tile tile;
//    while(true) 
//    {
//      tile = null;
//      if (stackSize() > 0)
//        tile = stackPop();
//      if (tile != null) {
//        Bitmap tileBitmap = loadFromDb(tile);
//        if (tileBitmap != null) {
//          mDbTileLoaderListener.onTileInDb(tile, tileBitmap);
//        } else {
//          mDbTileLoaderListener.onTileNotInDb(tile);
//        }
//      }
//      try 
//      {
//        synchronized (this) 
//        {
//          if(mTiles.size() == 0)
//          {
//            this.wait();
//          }
//        }
//        Thread.sleep(50);
//      } 
//      catch (InterruptedException e) 
//      {
//        break;
//      }
//    }
//  }
  
  private boolean stackHasTile(Tile aTile) {
    synchronized (this) {
      for (Tile tile : mTiles) {
        if (tile.key != null && tile.key.equals(aTile.key))
          return true;
      }
      return false;
    }
  }
  
  private Tile stackPop() {
    synchronized (this) {
      return mTiles.pop();
    }
  }

  private int stackSize() {
    synchronized (this) {
      return mTiles.size();
    }
  }
  
  public interface IDbTileLoaderListener {
    public void onTilesLoadedFromDb(Map<Tile, Bitmap> tileBitmapMap);
    public void onTilesNotLoadedFromDb(List<Tile> tiles);
  }
}

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