com.sampullara.util.http.XMLHttpRequest Maven / Gradle / Ivy

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package com.sampullara.util.http;

import com.google.common.util.concurrent.SettableFuture;
import org.eclipse.jetty.client.ContentExchange;
import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.util.concurrent.Future;

/**
 * Retrieve and parse XML document from an HTTP source.
 * 
 * User: sam
 * Date: May 7, 2010
 * Time: 5:04:42 PM
 */
public class XMLHttpRequest extends HttpRequest {
  private static DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
  private static DocumentBuilder db;

  static {
    try {
      db = dbf.newDocumentBuilder();
    } catch (ParserConfigurationException e) {
      throw new AssertionError("Failed to create document builder: " + e);
    }
  }

  public XMLHttpRequest(String url) throws MalformedURLException {
    super(url);
  }

  @Override
  public Future execute() throws IOException {
    final SettableFuture future = SettableFuture.create();
    ContentExchange exchange = new ContentExchange() {
      protected void onResponseComplete() throws IOException {
        super.onResponseComplete();
        String responseContent = this.getResponseContent();
        try {
          future.set(db.parse(new InputSource(responseContent)));
        } catch (SAXException e) {
          future.setException(e);
        }
      }
    };

    exchange.setRequestHeader("Accept", "text/xml, application/xml");
    exchange.setMethod("GET");
    exchange.setURL(url.toExternalForm());

    // start the exchange
    client.send(exchange);

    return future;
  }
}