network connections-httpconnectionhelper.java

RMS移动商务应用开发

/* License
 * 
 * Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  
 *  * Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *  * Redistribution in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *  
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *  
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility. 
 */

  import java.io.*;
  import javax.microedition.io.*;
   
  public class HttpConnectionHelper {
 
    public interface Callback {
      void prepareRequest( String originalURL,
                           HttpConnection conn )
           throws IOException;
    }
   
    public static HttpConnection connect( String url )
                                   throws IOException {
      return connect( url, null );
    }
   
    public static HttpConnection connect(
            String url, Callback callback )
                         throws IOException {
      HttpConnection conn = null;
      String         originalURL = url;
   
      while( url != null ){
        HttpConnection conn = (HttpConnection)
                          Connector.open( url );
   
        if( callback != null ){
          callback.prepareRequest( originalURL,
                                         conn );
        }
   
        int rc = conn.getResponseCode();
  
        switch( rc ){
            case HttpConnection.HTTP_MOVED_PERM:
            case HttpConnection.HTTP_MOVED_TEMP:
            case HttpConnection.HTTP_SEE_OTHER:
            case HttpConnection.HTTP_TEMP_REDIRECT:
              url = conn.getHeaderField( "Location" );

              if( url != null && url.startsWith(
                                            "/*" ) ){
                StringBuffer b = new StringBuffer();
                b.append( "http://" );
                b.append( conn.getHost() );
                b.append( ':' );
                b.append( conn.getPort() );
                b.append( url );
                url = b.toString();
              }
              conn.close();
              break;
            default:
              url = null;
              break;
        }
      }

      return conn;
   }
 }