ImageDownloadOperation.java

package external.GifImageViewEx.net.frakbot.imageviewex.operation;

import android.content.Context;
import android.os.Bundle;
import android.support.v4.util.LruCache;
import android.text.TextUtils;

import com.aiyou.utils.logcat.Logcat;
import com.jakewharton.disklrucache.DiskLruCache;
import com.jakewharton.disklrucache.DiskLruCache.Editor;

import external.GifImageViewEx.com.foxykeep.datadroid.exception.ConnectionException;
import external.GifImageViewEx.com.foxykeep.datadroid.exception.CustomRequestException;
import external.GifImageViewEx.com.foxykeep.datadroid.exception.DataException;
import external.GifImageViewEx.com.foxykeep.datadroid.requestmanager.Request;
import external.GifImageViewEx.com.foxykeep.datadroid.service.RequestService.Operation;
import external.GifImageViewEx.net.frakbot.cache.CacheHelper;
import external.GifImageViewEx.net.frakbot.imageviewex.ImageViewNext;
import external.GifImageViewEx.net.frakbot.imageviewex.requestmanager.ImageViewExRequestFactory;
import external.GifImageViewEx.net.frakbot.remote.RemoteHelper;

import java.io.IOException;

/**
 * Operation to download an image from the network. Requested input: -
 * ImageMemCacheOperation.PARAM_IMAGE_URL, the URL of the image Given output: -
 * ImageViewExRequestFactory.BUNDLE_EXTRA_OBJECT, the byte array of the image -
 * ImageViewExRequestFactory.BUNDLE_EXTRA_IMAGE_URL, the requested URL of the
 * image
 * 
 * @author Francesco Pontillo
 */
public class ImageDownloadOperation implements Operation {

    public static final String PARAM_IMAGE_URL = "net.frakbot.imageviewex.extra.url";

    @Override
    public Bundle execute(Context context, Request request)
            throws ConnectionException, DataException, CustomRequestException {

        // Initializes the caches, if they're not initialized already
        ImageViewNext.initCaches(context);

        // Get the URL from the input Bundle
        String url = request.getString(PARAM_IMAGE_URL);
        if (TextUtils.isEmpty(url))
            throw new DataException("No value for URL parameter");

        byte[] image;
        try {
            image = RemoteHelper.download(url);
        } catch (IOException e) {
            throw new DataException(
                    "NETWORK: Error while getting value for URL " + url);
        }

        // If the object is not null
        if (image != null) {
            // Save into the disk cache
            DiskLruCache diskCache = ImageViewNext.getDiskCache();
            try {
                Editor editor = diskCache.edit(CacheHelper
                        .UriToDiskLruCacheString(url));
                if (editor != null) {
                    if (CacheHelper.writeByteArrayToEditor(image, editor)) {
                        diskCache.flush();
                        editor.commit();
                    } else {
                        editor.abort();
                    }
                }
            } catch (Exception e) {
                Logcat.w(ImageDownloadOperation.class.getSimpleName(),
                        "Storage of image into the disk cache failed!");
            }
            // Save into the memory cache
            LruCache<String, byte[]> memCache = ImageViewNext.getMemCache();
            memCache.put(url, image);
        }

        Bundle b = new Bundle();
        b.putByteArray(ImageViewExRequestFactory.BUNDLE_EXTRA_OBJECT, image);
        b.putString(ImageViewExRequestFactory.BUNDLE_EXTRA_IMAGE_URL, url);
        return b;
    }

}