com.janoz.usenet.suppliers.impl.UrlBasedSupplier.java Source code

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Here is the source code for com.janoz.usenet.suppliers.impl.UrlBasedSupplier.java

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/*******************************************************************************
 * Copyright (c) 2010 Gijs de Vries aka Janoz.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Gijs de Vries aka Janoz - initial API and implementation
 ******************************************************************************/
package com.janoz.usenet.suppliers.impl;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.janoz.usenet.LazyInitializationException;
import com.janoz.usenet.model.NZB;
import com.janoz.usenet.suppliers.LazyNZBSupplier;
import com.janoz.usenet.support.Throttler;

public class UrlBasedSupplier implements LazyNZBSupplier {
    private static final Log LOG = LogFactory.getLog(UrlBasedSupplier.class);

    private Throttler throttler;

    @Override
    public byte[] getData(NZB nzb) {
        if (nzb.getUrl() == null) {
            throw new LazyInitializationException("Unable to fetch data. URL missing.");
        }
        if (throttler != null) {
            throttler.throttle();
        }
        InputStream is = null;
        try {
            URLConnection connection = new URL(nzb.getUrl()).openConnection();
            is = connection.getInputStream();
            int contentLength = connection.getContentLength();
            ByteArrayOutputStream baos;
            if (contentLength != -1) {
                baos = new ByteArrayOutputStream(contentLength);
            } else {
                baos = new ByteArrayOutputStream(16384); // Pick some appropriate size
            }

            byte[] buf = new byte[512];
            while (true) {
                int len = is.read(buf);
                if (len == -1) {
                    break;
                }
                baos.write(buf, 0, len);
            }
            return baos.toByteArray();
        } catch (MalformedURLException e) {
            LOG.error("Error in URL.", e);
            throw new LazyInitializationException("Error fetching NZB with URL  " + nzb.getUrl() + ".", e);
        } catch (IOException e) {
            LOG.error("IO error fetching lazy data.", e);
            throw new LazyInitializationException("IO error fetching NZB with URL  " + nzb.getUrl() + ".", e);
        } finally {
            if (throttler != null) {
                throttler.setThrottleForNextAction();
            }
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    LOG.info("error closing stream.", e);
                }
            }
        }
    }

    public void setThrottler(Throttler throttler) {
        this.throttler = throttler;
    }

}