|  The applet below demonstrates some of the capabilities of the 
              wrapper class methods. An integer and Boolean strings pass to the 
              applet via the <param= 
              > tags. We then need to convert 
              the strings to primitive type values. The Integer 
              and Boolean 
              classes provide methods to convert the strings to their respective 
              primitive values. For the Integer 
              class a single method - parseInt(param1) 
              - can do the operation. The Boolean 
              wrapper, however, does not include a "parseBoolean" 
              type of method to go directly from a string of "true" 
              or "false" 
              strings to a boolean value. Instead two Boolean 
              methods are required.   
              
                 
                  | WrapperApplet.java (Output goes to browser's Java 
                    console.)
 |   
                  | The tag in the web page will look like:  
                       <applet 
                        code="WrapperApplet.class" codebase =   "../../Code/Java/Wrappers/Basic/" 
                        width=100 height=50><param name="param1" value="1234">
 <param name="param2" value="true">
 </applet>
 
 |   
                  |  public 
                      class WrapperApplet extends java.applet.Applet{
 public void init () {
 //Create an instance of the Test 
                      class
 Test test = new Test ();
 
 // First parameter is an integer 
                      string
 String param1= getParameter ("param1");
 // Use a method in the Integer wrapper 
                      to convert the
 // string to an int type value.
 int val1 = Integer.parseInt (param1);
 
 // Second parameter is a boolean 
                      string.
 String param2 = getParameter ("param2");
 
 // Use the methods in the Boolean 
                      wrapper class
 // to convert the "true" or "false" 
                      strings to
 // boolean values in 2 steps:
 Boolean b = Boolean.valueOf (param2);
 boolean flag = b.booleanValue ();
 
 // Java 5.0 added the parseBoolean() 
                      method
 // so you can now do this in one 
                      step:
 //
 //   boolean flag = b.parseBoolean(param2);
 
 // Now that you have the two parameters 
                      converted
 // to their respective primitive 
                      type values, you
 // could, for example, use the boolean 
                      as a flag
 // to select between 2 different 
                      initialization methods
 // and pass the integer value to 
                      either.
 if (flag)
 test.aMethod 
                      (val1);
 else
 test.bMethod 
                      (val1);
 }
 
 // Paint message in Applet window.
 public void paint (java.awt.Graphics g) {
 g.drawString ("WrapperApplet", 
                      20, 20);
 }
 }
 
 // Use Test to examine various aspects of class design
 class Test
 {
 void aMethod (int i) {
 // Use the explicit String method 
                      to convert
 // an int to a String object.
 String iStr = String.valueOf (i);
 
 System.out.println (iStr + " in 
                      aMethod");
 System.out.println ();
 }
 
 void bMethod (int i) {
 String iStr = String.valueOf (i);
 System.out.println (iStr + " in 
                      bMethod");
 System.out.println ();
 }
 }
 |   
                  |  |    Latest update: Oct. 19, 2004 |