001 // Copyright 2004, 2005 The Apache Software Foundation
002 //
003 // Licensed under the Apache License, Version 2.0 (the "License");
004 // you may not use this file except in compliance with the License.
005 // You may obtain a copy of the License at
006 //
007 // http://www.apache.org/licenses/LICENSE-2.0
008 //
009 // Unless required by applicable law or agreed to in writing, software
010 // distributed under the License is distributed on an "AS IS" BASIS,
011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012 // See the License for the specific language governing permissions and
013 // limitations under the License.
014
015 package org.apache.tapestry.form;
016
017 import org.apache.tapestry.IMarkupWriter;
018 import org.apache.tapestry.IRequestCycle;
019 import org.apache.tapestry.valid.IValidationDelegate;
020 import org.apache.tapestry.valid.ValidatorException;
021
022 /**
023 * Implements a component that manages an HTML <input type=checkbox> form element. [ <a
024 * href="../../../../../ComponentReference/Checkbox.html">Component Reference </a>]
025 * <p>
026 * As of 4.0, this component can be validated.
027 *
028 * @author Howard Lewis Ship
029 * @author Paul Ferraro
030 */
031 public abstract class Checkbox extends AbstractFormComponent implements ValidatableField
032 {
033 /**
034 * @see org.apache.tapestry.form.validator.AbstractRequirableField#renderRequirableFormComponent(org.apache.tapestry.IMarkupWriter,
035 * org.apache.tapestry.IRequestCycle)
036 */
037 protected void renderFormComponent(IMarkupWriter writer, IRequestCycle cycle)
038 {
039 renderDelegatePrefix(writer, cycle);
040
041 writer.beginEmpty("input");
042 writer.attribute("type", "checkbox");
043
044 writer.attribute("name", getName());
045
046 if (isDisabled())
047 writer.attribute("disabled", "disabled");
048
049 // write out submitted input for case of validation errors
050
051 IValidationDelegate delegate = getForm().getDelegate();
052 boolean checked = getValue();
053 if (delegate != null && delegate.isInError()) {
054
055 checked = Boolean.valueOf(delegate.getFieldInputValue()).booleanValue();
056 }
057
058 if (checked) {
059 writer.attribute("checked", "checked");
060 }
061
062 renderIdAttribute(writer, cycle);
063
064 getValidatableFieldSupport().renderContributions(this, writer, cycle);
065
066 renderInformalParameters(writer, cycle);
067
068 writer.closeTag();
069
070 renderDelegateSuffix(writer, cycle);
071 }
072
073 /**
074 * In traditional HTML, many checkboxes would have the same name but different values. Under
075 * Tapestry, it makes more sense to have different names and a fixed value. For a checkbox, we
076 * only care about whether the name appears as a request parameter.
077 */
078 protected void rewindFormComponent(IMarkupWriter writer, IRequestCycle cycle)
079 {
080 String value = cycle.getParameter(getName());
081
082 try
083 {
084 // This is atypical validation - since this component does not explicitly bind to an object
085
086 getValidatableFieldSupport().validate(this, writer, cycle, value);
087
088 setValue(value != null);
089 }
090 catch (ValidatorException e)
091 {
092 getForm().getDelegate().record(e);
093 getForm().getDelegate().recordFieldInputValue(Boolean.valueOf(value).toString());
094 }
095 }
096
097 public abstract boolean getValue();
098
099 public abstract void setValue(boolean selected);
100
101 /**
102 * Injected.
103 */
104 public abstract ValidatableFieldSupport getValidatableFieldSupport();
105
106 /**
107 * @see org.apache.tapestry.form.AbstractFormComponent#isRequired()
108 */
109 public boolean isRequired()
110 {
111 return getValidatableFieldSupport().isRequired(this);
112 }
113 }