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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 URL
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. NOTE: The
DataHandler object creates a URLDataSource internally,
when it is constructed with a URL.

See Also:
Since:1.6
/**
 * 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.

Params:
  • url – The URL to be encapsulated in this object.
/**
     * 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 URLConnection.getContentType method
after retrieving a URLConnection object.
Note: this method attempts to call the openConnection
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.

Returns:the content type.
/**
     * 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 getFile method on the URL used to
instantiate the object.

Returns:the result of calling the URL's getFile method.
/**
     * 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
openStream method on the URL.

Returns:the InputStream.
/**
     * 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.

Returns:the OutputStream.
/**
     * 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.

Returns:The URL.
/**
     * Return the URL used to create this DataSource.
     *
     * @return The URL.
     */
    public URL getURL() {
        return url;
    }
}