/*

 * Copyright 1997-2005 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.activation;

import java.net.URL;

import java.net.URLConnection;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.IOException;

/**

 * The URLDataSource class provides an object that wraps a <code>URL</code>

 * object in a DataSource interface. URLDataSource simplifies the handling

 * of data described by URLs within the JavaBeans Activation Framework

 * because this class can be used to create new DataHandlers. <i>NOTE: The

 * DataHandler object creates a URLDataSource internally,

 * when it is constructed with a URL.</i>

 *

 * @see javax.activation.DataSource

 * @see javax.activation.DataHandler

 *

 * @since 1.6

 */

public class URLDataSource implements DataSource {

    private URL url = null;

    private URLConnection url_conn = null;

    /**

     * URLDataSource constructor. The URLDataSource class will

     * not open a connection to the URL until a method requiring it

     * to do so is called.

     *

     * @param url The URL to be encapsulated in this object.

     */

    public URLDataSource(URL url) {

        this.url = url;

    }

    /**

     * Returns the value of the URL content-type header field.

     * It calls the URL's <code>URLConnection.getContentType</code> method

     * after retrieving a URLConnection object.

     * <i>Note: this method attempts to call the <code>openConnection</code>

     * method on the URL. If this method fails, or if a content type is not

     * returned from the URLConnection, getContentType returns

     * "application/octet-stream" as the content type.</i>

     *

     * @return the content type.

     */

    public String getContentType() {

        String type = null;

        try {

            if (url_conn == null)

                url_conn = url.openConnection();

        } catch (IOException e) { }

        if (url_conn != null)

            type = url_conn.getContentType();

        if (type == null)

            type = "application/octet-stream";

        return type;

    }

    /**

     * Calls the <code>getFile</code> method on the URL used to

     * instantiate the object.

     *

     * @return the result of calling the URL's getFile method.

     */

    public String getName() {

        return url.getFile();

    }

    /**

     * The getInputStream method from the URL. Calls the

     * <code>openStream</code> method on the URL.

     *

     * @return the InputStream.

     */

    public InputStream getInputStream() throws IOException {

        return url.openStream();

    }

    /**

     * The getOutputStream method from the URL. First an attempt is

     * made to get the URLConnection object for the URL. If that

     * succeeds, the getOutputStream method on the URLConnection

     * is returned.

     *

     * @return the OutputStream.

     */

    public OutputStream getOutputStream() throws IOException {

        // get the url connection if it is available

        url_conn = url.openConnection();

        if (url_conn != null) {

            url_conn.setDoOutput(true);

            return url_conn.getOutputStream();

        } else

            return null;

    }

    /**

     * Return the URL used to create this DataSource.

     *

     * @return The URL.

     */

    public URL getURL() {

        return url;

    }

}