booktitleserviceviaservlets.java

java web services how to program

// Fig. 14.10: BookTitleServiceViaServlets.java.
// BookTitleServiceViaServlets connects to a servlet that
// makes a request to the Book Titles Web service.
package com.deitel.jws1.j2me.client;

// import J2ME packages
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import java.io.*;

// import Deitel packages
import com.deitel.jws1.services.BookTitles;

public class BookTitleServiceViaServlets
   implements BookTitles {
 
   // URL of servlet that accesses Book Titles Web service
   private final static String SERVICE_URL = 
      "http://localhost:8080/j2me/BookTitlesProxy";

   // invoke Book Titles Web service via servlet
   public String[] getBookTitles()
   {
      // invoke Web service and convert result to String array
      try {

         // establish HTTP connection to servlet
         HttpConnection httpConnection = 
           ( HttpConnection ) Connector.open( SERVICE_URL );

         // receive server data
         String titles[] = getData( httpConnection );

         httpConnection.close(); // close connection

         return titles;
      }

      // handle exception communicating with HTTP server
      catch ( IOException ioException ) {
         ioException.printStackTrace();
         return null;
      }

   } // end method getBookTitles

   // open DataInputStream to receive data
   private String[] getData( HttpConnection httpConnection )
      throws IOException
   {
      StringBuffer data = new StringBuffer();

      // open input stream from connection
      InputStream inputStream = ( DataInputStream )
         httpConnection.openDataInputStream();

      int inputCharacter = inputStream.read();

      // read all data
      while ( inputCharacter != -1 ) {
         data.append( ( char ) inputCharacter );
         inputCharacter = inputStream.read();
      }

      inputStream.close(); // close stream

      // convert data to String array
      return parseData( data.toString(), '\n' );

   } // end method getData

   // string tokenizer parses String into sub-String array
   private String[] parseData( String data, char delimiter )
   {
      int newLines = 0;

      // determine number of delimiter characters in String
      for ( int i = 0; i < data.length(); i++ )

         // increase number of delimiters by one
         if ( data.charAt( i ) == delimiter )
            newLines++;

      // create String array to hold String tokens
      String list[] = new String[ newLines ];

      int oldNewLineIndex = 0;
      int currentNewLineIndex;

      // store Strings into array based on demiliter
      for ( int i = 0; i < newLines; i++ ) {

         // determine index where delimiter occurs
         currentNewLineIndex = 
            data.indexOf( delimiter, oldNewLineIndex );

         // extract String within delimiter characters
         list[ i ] = data.substring( oldNewLineIndex, 
            currentNewLineIndex - 1 );

         oldNewLineIndex = currentNewLineIndex + 1;
      }

      return list;

   } // end method parseData

} // end class BookTitleServiceViaServlets