AbstractResourceFetcher.java

package org.eclipse.buckminster.fetcher;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.ecf.core.util.Base64;
import org.eclipse.osgi.util.NLS;

/**
 * Base class for {@link IResourceFetcher}. Provides authentication and fetch
 * entry point for children classes. Also creates destination directory if
 * needed.
 * 
 * @author Guillaume CHATELET
 */
public abstract class AbstractResourceFetcher implements IResourceFetcher {
	private final URL url;

	private final String destinationDir;

	private String login;

	private String password;

	public AbstractResourceFetcher(URL url, String dir) {
		this.url = url;
		this.destinationDir = dir;
	}

	@Override
	public void fetch(IProgressMonitor monitor) throws IOException, CoreException {
		URLConnection conn = null;
		InputStream in = null;
		try {
			conn = url.openConnection();
			if (login != null) {
				final String userPassword = login + ':' + password;
				final String encoding = Base64.encode(userPassword.getBytes());
				conn.setRequestProperty("Authorization", "Basic " + encoding); //$NON-NLS-1$ //$NON-NLS-2$
			}
			in = conn.getInputStream();
			monitor.subTask(NLS.bind(Messages.preparing_destination_folder_0, destinationDir));
			prepareDirectories(destinationDir);
			monitor.subTask(NLS.bind(Messages.fetching_0, getUrl().toString()));
			consume(new BufferedInputStream(in), monitor);
		} finally {
			try {
				if (in != null) {
					in.close();
				}
			} catch (IOException ioe) {
			}
		}
	}

	@Override
	public void setBasicAuthCredential(String login, String password) {
		if (login == null || password == null)
			throw new NullPointerException(Messages.login_and_password_must_be_not_null);
		this.login = login;
		this.password = password;
	}

	protected abstract void consume(InputStream stream, IProgressMonitor monitor) throws IOException, CoreException;

	final protected String getDestinationDir() {
		return destinationDir;
	}

	protected URL getUrl() {
		return url;
	}

	final private void prepareDirectories(String dir) {
		new File(dir).mkdirs();
	}
}