fi.kinetik.android.currencies.spi.openexchange.OpenExchangeRatesSpi.java Source code

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Here is the source code for fi.kinetik.android.currencies.spi.openexchange.OpenExchangeRatesSpi.java

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/*
 * Copyright 2011 Kinetik Oy http://www.kinetik.fi
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package fi.kinetik.android.currencies.spi.openexchange;

import android.content.ContentProviderOperation;
import fi.kinetik.android.currencies.spi.RatesSpi;
import fi.kinetik.android.currencies.spi.RatesSpiException;
import fi.kinetik.android.currencies.provider.CurrencyContract.ConversionRate;
import fi.kinetik.android.currencies.util.IOUtils;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Iterator;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * 
 * Expected JSON format:
 * <code> 
 * {
 *   "disclaimer": "disclaimer text",
 *   "license": "copyright text",
 *   "timestamp": 1324116096,
 *   "base": "USD",
 *   "rates": {
 *      "AED": 3.673,
 *      "AFN": 42.950001
 *   }
 * }
 * </code>
 *
 * @author jsr
 */
public class OpenExchangeRatesSpi implements RatesSpi {

    private static final String TAG = "RatesSpi";

    /* package */ OpenExchangeRatesSpi() {
    }

    public void loadData(ArrayList<ContentProviderOperation> operations) throws IOException, RatesSpiException {

        final URLConnection connection = OpenExchangeRatesSpiFactory.sFeedURL.openConnection();

        InputStream in = null;

        try {

            in = connection.getInputStream();

            // not efficient to read the entire feed into memory but since its
            // not that big...

            JSONObject json = new JSONObject(IOUtils.toString(in, OpenExchangeRatesSpiFactory.CHARSET));

            parseRates(operations, json);

        } catch (JSONException e) {
            throw new RatesSpiException("parsing json failed", e);
        } finally {
            IOUtils.close(in);
        }
    }

    private void parseRates(ArrayList<ContentProviderOperation> operations, JSONObject jsonObj)
            throws JSONException {

        final long updated = jsonObj.getLong(Keys.TIMESTAMP);
        final String base = jsonObj.getString(Keys.BASE);
        final JSONObject rates = jsonObj.getJSONObject(Keys.RATES);
        final Iterator iter = rates.keys();

        while (iter.hasNext()) {

            final String currency = (String) iter.next();
            final double rate = rates.getDouble(currency);

            operations.add(ConversionRate.newUpdateOperation(currency, OpenExchangeRatesSpiFactory.PROVIDER_NAME,
                    updated, rate));
        }

    }

    public String getProviderName() {
        return OpenExchangeRatesSpiFactory.PROVIDER_NAME;
    }

    interface Keys {

        String TIMESTAMP = "timestamp";

        String BASE = "base";

        String RATES = "rates";

    }

}