1 /*

     2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.

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

     4  *

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

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

     7  * published by the Free Software Foundation.  Oracle designates this

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

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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

    15  * accompanied this code).

    16  *

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

    18  * 2 along with this work; if not, write to the Free Software Foundation,

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

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 package javax.activation;

    27 

    28 import java.net.URL;

    29 import java.net.URLConnection;

    30 import java.io.InputStream;

    31 import java.io.OutputStream;

    32 import java.io.IOException;

    33 

    34 /**

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

    36  * object in a DataSource interface. URLDataSource simplifies the handling

    37  * of data described by URLs within the JavaBeans Activation Framework

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

    39  * DataHandler object creates a URLDataSource internally,

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

    41  *

    42  * @see javax.activation.DataSource

    43  * @see javax.activation.DataHandler

    44  *

    45  * @since 1.6

    46  */

    47 public class URLDataSource implements DataSource {

    48     private URL url = null;

    49     private URLConnection url_conn = null;

    50 

    51     /**

    52      * URLDataSource constructor. The URLDataSource class will

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

    54      * to do so is called.

    55      *

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

    57      */

    58     public URLDataSource(URL url) {

    59         this.url = url;

    60     }

    61 

    62     /**

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

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

    65      * after retrieving a URLConnection object.

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

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

    68      * returned from the URLConnection, getContentType returns

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

    70      *

    71      * @return the content type.

    72      */

    73     public String getContentType() {

    74         String type = null;

    75 

    76         try {

    77             if (url_conn == null)

    78                 url_conn = url.openConnection();

    79         } catch (IOException e) { }

    80 

    81         if (url_conn != null)

    82             type = url_conn.getContentType();

    83 

    84         if (type == null)

    85             type = "application/octet-stream";

    86 

    87         return type;

    88     }

    89 

    90     /**

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

    92      * instantiate the object.

    93      *

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

    95      */

    96     public String getName() {

    97         return url.getFile();

    98     }

    99 

   100     /**

   101      * The getInputStream method from the URL. Calls the

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

   103      *

   104      * @return the InputStream.

   105      */

   106     public InputStream getInputStream() throws IOException {

   107         return url.openStream();

   108     }

   109 

   110     /**

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

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

   113      * succeeds, the getOutputStream method on the URLConnection

   114      * is returned.

   115      *

   116      * @return the OutputStream.

   117      */

   118     public OutputStream getOutputStream() throws IOException {

   119         // get the url connection if it is available

   120         url_conn = url.openConnection();

   121 

   122         if (url_conn != null) {

   123             url_conn.setDoOutput(true);

   124             return url_conn.getOutputStream();

   125         } else

   126             return null;

   127     }

   128 

   129     /**

   130      * Return the URL used to create this DataSource.

   131      *

   132      * @return The URL.

   133      */

   134     public URL getURL() {

   135         return url;

   136     }

   137 }