org.devtcg.five.meta.LastfmMetaTask.java Source code

Introduction

Here is the source code for org.devtcg.five.meta.LastfmMetaTask.java

Source

/*
 * Copyright (C) 2009 Josh Guilfoyle <jasta@devtcg.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

package org.devtcg.five.meta;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.devtcg.five.util.HttpUtils;
import org.devtcg.five.util.IOUtils;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
import org.xml.sax.helpers.XMLReaderFactory;

public abstract class LastfmMetaTask implements Callable<Object> {
    protected static final Log LOG = LogFactory.getLog(LastfmMetaTask.class);

    private static final String API_KEY = "3edc5156fb5dc2d185c1f00ba0282ea5";
    protected static final String LASTFM_CALL_URL = "http://ws.audioscrobbler.com/2.0/?api_key=" + API_KEY;

    protected static final HttpClient mClient = HttpUtils.newHttpClient();

    protected static final int THUMB_WIDTH = 64;
    protected static final int THUMB_HEIGHT = 64;

    protected final MetaProvider mProvider;
    private final FutureTask<?> mTask;
    protected final long mId;
    protected DefaultHandler mXmlHandler;

    public LastfmMetaTask(MetaProvider provider, long id) {
        mProvider = provider;
        mTask = new FutureTask<Object>(this);
        mId = id;
    }

    public FutureTask<?> getTask() {
        return mTask;
    }

    public Object call() throws Exception {
        try {
            run();
        } catch (Exception e) {
            if (LOG.isWarnEnabled())
                LOG.warn("Error accessing Last.fm", e);
        }
        return null;
    }

    protected abstract String getMethodUrl();

    protected abstract DefaultHandler getContentHandler();

    protected abstract void onPostParse();

    public void run() throws Exception {
        System.out.println("Accessing " + getMethodUrl());
        HttpGet request = new HttpGet(getMethodUrl());

        HttpResponse response = mClient.execute(request);

        if (mTask.isCancelled())
            return;

        if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
            if (LOG.isWarnEnabled())
                LOG.warn(getMethodUrl() + " replied " + response.getStatusLine());
            response.getEntity().consumeContent();
            return;
        }

        HttpEntity entity = response.getEntity();
        InputStream in = entity.getContent();

        try {
            XMLReader reader = XMLReaderFactory.createXMLReader();
            reader.setContentHandler(getContentHandler());
            reader.parse(new InputSource(in));
        } finally {
            IOUtils.closeQuietlyNullSafe(in);
        }

        if (mTask.isCancelled())
            return;

        onPostParse();
    }

    protected byte[] downloadImage(String url) throws IOException {
        System.out.println("Fetching " + url);
        HttpGet request = new HttpGet(url);

        HttpResponse response = mClient.execute(request);

        if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
            if (LOG.isWarnEnabled())
                LOG.warn(url + " replied " + response.getStatusLine());
            response.getEntity().consumeContent();
            return null;
        }

        HttpEntity entity = response.getEntity();

        ByteArrayOutputStream out = new ByteArrayOutputStream((int) entity.getContentLength());
        InputStream in = entity.getContent();

        try {
            IOUtils.copyStream(in, out);
            return out.toByteArray();
        } finally {
            IOUtils.closeQuietlyNullSafe(in);
        }
    }
}