WebImageManagerRetriever.java

//
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//
//
//  Copyright (c) 2015-2016, Geek Zoo Studio
//  http://www.geek-zoo.com
//
//
//  Permission is hereby granted, free of charge, to any person obtaining a
//  copy of this software and associated documentation files (the "Software"),
//  to deal in the Software without restriction, including without limitation
//  the rights to use, copy, modify, merge, publish, distribute, sublicense,
//  and/or sell copies of the Software, and to permit persons to whom the
//  Software is furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
//  IN THE SOFTWARE.
//

package com.BeeFramework.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import com.BeeFramework.model.BeeCallback;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

public class WebImageManagerRetriever extends AsyncTask<Void, Void, Bitmap> {
	private final static String TAG = WebImageManagerRetriever.class.getSimpleName();

	// cache
	private static WebImageCache mCache;
	
	// what we're looking for
	private Context mContext;
	private String mURLString;
	private int mDiskCacheTimeoutInSeconds = -1;
	private OnWebImageLoadListener mListener;
	
	static {
		mCache = new WebImageCache();
	}
	
	public WebImageManagerRetriever(Context context, String urlString, int diskCacheTimeoutInSeconds, OnWebImageLoadListener listener) {
		mContext = context;
		mURLString = urlString;
		mDiskCacheTimeoutInSeconds = diskCacheTimeoutInSeconds;
		mListener = listener;
	}
	
	@Override
	protected Bitmap doInBackground(Void... params) {
		// check mem cache first
		Bitmap bitmap = mCache.getBitmapFromMemCache(mURLString);

		// check disk cache first
		if (bitmap == null) {
			bitmap = mCache.getBitmapFromDiskCache(mContext, mURLString, mDiskCacheTimeoutInSeconds);
			mCache.addBitmapToMemCache(mURLString, bitmap);
		}
		
		if (bitmap == null) {
			InputStream is = null;
			FlushedInputStream fis = null;
			
			try {
				URL url = new URL(mURLString);
				URLConnection conn = url.openConnection();
				
				is = conn.getInputStream();
                int length = is.available();

                BeeCallback.incrementBandwidthUsedInLastSecond(length);

				fis = new FlushedInputStream(is);
				
				bitmap = BitmapFactory.decodeStream(fis);

				// cache
				if (bitmap != null) {
					mCache.addBitmapToCache(mContext, mURLString, bitmap);
				}
			} catch (Exception ex) {
				Log.e(TAG, "Error loading image from URL " + mURLString + ": " + ex.toString());
			} finally {
				try {
					is.close();
				} catch (Exception ex) {}
			}
		}

		return bitmap;
	}

	@Override
    protected void onPostExecute(Bitmap bitmap) {
		// complete!
	    if (null != mListener) {
	        if (null == bitmap) {
	            mListener.onWebImageError();
	        } else {
	            mListener.onWebImageLoad(mURLString, bitmap);
	        }
	    }
    }

    static class FlushedInputStream extends FilterInputStream {
        public FlushedInputStream(InputStream inputStream) {
            super(inputStream);
        }

        @Override
        public long skip(long n) throws IOException {
            long totalBytesSkipped = 0L;
            
            while (totalBytesSkipped < n) {
                long bytesSkipped = in.skip(n - totalBytesSkipped);
                
                if (bytesSkipped == 0L) {
                    int b = read();
                    
                    if (b < 0) {
                        break;  // we reached EOF
                    } else {
                        bytesSkipped = 1; // we read one byte
                    }
                }
                
                totalBytesSkipped += bytesSkipped;
            }
            
            return totalBytesSkipped;
        }
    }

    public interface OnWebImageLoadListener {
        public void onWebImageLoad(String url, Bitmap bitmap);
        public void onWebImageError();
    }
}