Submit


1   // Copyright 2004, 2005 The Apache Software Foundation
2   //
3   // Licensed under the Apache License, Version 2.0 (the "License");
4   // you may not use this file except in compliance with the License.
5   // You may obtain a copy of the License at
6   //
7   //     http://www.apache.org/licenses/LICENSE-2.0
8   //
9   // Unless required by applicable law or agreed to in writing, software
10  // distributed under the License is distributed on an "AS IS" BASIS,
11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  // See the License for the specific language governing permissions and
13  // limitations under the License.
14  
15  package org.apache.tapestry.form;
16  
17  import org.apache.tapestry.IMarkupWriter;
18  import org.apache.tapestry.IRequestCycle;
19  
20  /**
21   * Implements a component that manages an HTML &lt;input type=submit&gt; form element. [ <a
22   * HREF="../../../../../ComponentReference/Submit.html">Component Reference </a>]
23   * <p>
24   * This component is generally only used when the form has multiple submit buttons, and it is
25   * important for the application to know which one was pressed. You may also want to use
26   * {@link ImageSubmit}which accomplishes much the same thing, but uses a graphic image instead.
27   * 
28   * @author Howard Lewis Ship
29   */
30  
31  public abstract class Submit extends AbstractSubmit
32  {
33      protected boolean isClicked(IRequestCycle cycle, String   name)
34      {
35          // How to know which Submit button was actually
36          // clicked? When submitted, it produces a request parameter
37          // with its name and value (the value serves double duty as both
38          // the label on the button, and the parameter value).
39  
40          // If the value isn't there, then this button wasn't
41          // selected.
42          return cycle.getParameter(name) != null;
43      }
44  
45      /**
46       * @see org.apache.tapestry.form.AbstractFormComponent#renderFormComponent(org.apache.tapestry.IMarkupWriter,
47       *      org.apache.tapestry.IRequestCycle)
48       */
49      protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
50      {
51          writer.beginEmpty("input");
52          writer.attribute("type", "submit");
53          writer.attribute("name", getName());
54  
55          if (isDisabled())
56              writer.attribute("disabled", "disabled");
57  
58          String   label = getLabel();
59  
60          if (label != null)
61              writer.attribute("value", label);
62  
63          renderIdAttribute(writer, cycle);
64  
65          renderInformalParameters(writer, cycle);
66  
67          writer.closeTag();
68      }
69  
70      /** parameter */
71      public abstract String   getLabel();
72  
73  }
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