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<title>HttpUnit Tutorial - create pool editor - step 3</title>
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<p class="location"><a href="index.html">Tutorial</a>
<img src="arrow_yellow.gif" width=13 height=9 align=bottom ALT="->"> <a href="task1.html">Task 1</a>
<img src="arrow_yellow.gif" width=13 height=9 align=bottom ALT="->"> Step 3: Submitting edits</p>
<h1>Submitting a Form</h1>
<p class="goals">In this step, you will learn how to:
<br />• Check form default parameter values
<br />• Create a request from a form
<br />• Override the default parameter values in a request
<br />• Submit a form and get a response</p>
<p>We now have a form which can generate POST requests to define the betting pool. Our next step will be to build
the code which handles these requests. We will start by simply recording changes, and defer validation until the
administrator attempts to open the pool. For our demonstration application, we will use in-memory persistence only, and
will provide ourselves with a way to clear it so that each <code>JUnit</code> test can run independantly.
<h2>Testing pool display</h2>
<p>The first thing we want to test and implement is the display of the current state of the pool. We will do this by
setting the state directly, using the supplied entity classes and then invoke the form to display the pool. At this time,
we will also add the set up code to clear the pool before each test:</p>
<pre class="test-code">
<b>public void</b> setUp() <b>throws</b> Exception {
BettingPool.reset();
}
<b>public void</b> testPoolDisplay() <b>throws</b> Exception {
BettingPool.getGames()[0].setAwayTeam( "New York Jets" ); // (1) set up data
BettingPool.getGames()[0].setHomeTeam( "Philadelphia Eagles" );
BettingPool.getGames()[2].setAwayTeam( "St. Louis Rams" );
BettingPool.getGames()[2].setHomeTeam( "Chicago Bears" );
BettingPool.setTieBreakerIndex(2);
ServletRunner sr = <b>new</b> ServletRunner( "web.xml" );
ServletUnitClient client = sr.newClient();
client.setAuthorization( "aUser", "pool-admin" );
WebResponse response = client.getResponse( "http://localhost/PoolEditor" );
WebForm form = response.getFormWithID( "pool" );
assertNotNull( "No form found with ID 'pool'", form );
assertEquals( "Away team 0", "New York Jets", form.getParameterValue( "away0" ) ); // (2) check team names
assertEquals( "Home team 0", "Philadelphia Eagles", form.getParameterValue( "home0" ) );
assertEquals( "Away team 1", "", form.getParameterValue( "away1" ) );
assertEquals( "Home team 1", "", form.getParameterValue( "home1" ) );
assertEquals( "Away team 2", "St. Louis Rams", form.getParameterValue( "away2" ) );
assertEquals( "Home team 2", "Chicago Bears", form.getParameterValue( "home2" ) );
assertEquals( "Tie breaker game", "2", form.getParameterValue( "tiebreaker" ) ); // (3) check radio button
}
</pre>
<p>Here we are:<ol>
<li>Setting up the data that the servlet which read to create the entry form. Here we are using a simple in-memory
persistence strategy. If the servlet accessed the database, we would have to do JDBC calls here.</li>
<li>Reading the names of the teams and comparing them to what we initialized. Note the test for the skipped game to
verify that the defaults come through.</li>
<li>Checking the state of the radio button. Note that we can use the same method <code>WebForm.getParameterValue</code>
for each parameter, no matter its type.</li></ol></p>
<p>As before, the above test should initially fail. We then make it work by changing the loop in <code>printBody</code>
as follows:</p>
<pre class="servlet-code">
BettingPoolGame[] games = BettingPool.getGames();
<b>for</b> (int i = 0; i < games.length; i++) {
pw.println( "<tr><td><input name='home" + i + "' value='" + games[i].getHomeTeam() + "' ></td>" );
pw.println( "<td><input name='away" + i + "' value='" + games[i].getAwayTeam() + "'></td>" );
pw.print( "<td><input type='radio' name='tiebreaker' value='" + i + "'" );
if (i == BettingPool.getTieBreakerIndex()) pw.print( " checked" );
pw.println( " /></td></tr>" );
}
</pre>
<h2>Testing pool entry</h2>
<p>Now that we know we can display the current state of the pool, we will verify that we can use the form to change it
as well:<p />
<pre class="test-code">
<b>public void</b> testPoolEntry() <b>throws</b> Exception {
ServletRunner sr = <b>new</b> ServletRunner( "web.xml" );
ServletUnitClient client = sr.newClient();
client.setAuthorization( "aUser", "pool-admin" );
WebResponse response = client.getResponse( "http://localhost/PoolEditor" );
WebForm form = response.getFormWithID( "pool" );
assertNotNull( "No form found with ID 'pool'", form );
form.setParameter( "away1", "Detroit Lions" ); // (1) enter values into the form
form.setParameter( "home1", "Denver Broncos" );
form.setParameter( "tiebreaker", "1" );
SubmitButton saveButton = form.getSubmitButton( "save", "Save" ); // (2) select the desired submit button
response = form.submit( saveButton ); // (3) submit the form
assertEquals( "Away team 0", "", form.getParameterValue( "away0" ) ); // (4) verify the response
assertEquals( "Home team 0", "", form.getParameterValue( "home0" ) );
assertEquals( "Away team 1", "Detroit Lions", form.getParameterValue( "away1" ) );
assertEquals( "Home team 1", "Denver Broncos", form.getParameterValue( "home1" ) );
assertEquals( "Tie breaker game", "1", form.getParameterValue( "tiebreaker" ) );
}
</pre>
<p>This is our first form submission. Take note:<ol>
<li>We make a call for each parameter that we want to set. Any parameters we do not set will be submitted with their
default values.</li>
<li>Since there is more than one button in the form, we ask for the one we want by name and value.</li>
<li>We submit the form, specifying the desired button.</li>
<li>We can use the same methods as above to check the new state of the pool. Alternately, we could have examined the
BettingPool object directly.</li></ol></p>
<p>This test will fail with a 405 response, since we have not defined a handler for the POST message.
We do so now:</p>
<pre class="servlet-code">
<b>protected void</b> doPost( HttpServletRequest request, HttpServletResponse response )
<b>throws</b> ServletException, IOException {
updateBettingPool( request );
response.setContentType( "text/html" );
PrintWriter pw = response.getWriter();
pw.println( "<html><head></head><body>" );
printBody( pw );
pw.println( "</body></html>" );
}
<b>void</b> updateBettingPool( HttpServletRequest request ) {
BettingPoolGame[] games = BettingPool.getGames();
<b>for</b> (int i = 0; i < games.length; i++) {
games[i].setAwayTeam( request.getParameter( "away" + i ) );
games[i].setHomeTeam( request.getParameter( "home" + i ) );
}
BettingPool.setTieBreakerIndex( getTieBreakerIndex( request ) );
}
<b>private</b> int getTieBreakerIndex( HttpServletRequest request ) {
<b>try</b> {
<b>return</b> Integer.parseInt( request.getParameter( "tiebreaker" ) );
} <b>catch</b> (NumberFormatException e) {
<b>return</b> 0;
}
}
</pre>
<p>Note that we are using the same <code>printBody</code> method as the <code>doGet</code> method does.</p>
<p>We now have the ability to edit the pool entries. Our <a href="task1editor-validation.html">next step</a> is to add
the validation and handle opening the pool to bettors.
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