ImageDiskCacheOperation.java

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

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

import com.jakewharton.disklrucache.DiskLruCache;
import com.jakewharton.disklrucache.DiskLruCache.Snapshot;

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.Converters;
import external.GifImageViewEx.net.frakbot.imageviewex.ImageViewNext;
import external.GifImageViewEx.net.frakbot.imageviewex.requestmanager.ImageViewExRequestFactory;

/**
 * Operation to search for an image in the disk cache. 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 ImageDiskCacheOperation 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 {

        // Get the URL from the input Bundle
        String url = request.getString(PARAM_IMAGE_URL);
        if (url == null || url.equals(""))
            throw new DataException("No value for URL " + url);

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

        // Get the entry
        DiskLruCache diskCache = ImageViewNext.getDiskCache();
        Snapshot cacheEntry = null;
        try {
            cacheEntry = diskCache
                    .get(CacheHelper.UriToDiskLruCacheString(url));
        } catch (Exception e) {
            throw new DataException(
                    "DISK CACHE: Error while getting value for URL " + url);
        }

        byte[] image = null;

        // If the object is not null, convert it
        if (cacheEntry != null) {
            // Convert the InputStream
            image = Converters
                    .inputStreamToByteArray(cacheEntry.getInputStream(0),
                            (int) cacheEntry.getLength(0));

            // Saves the image in the in-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;
    }

}