| // Copyright 2013 The Apache Software Foundation |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package org.apache.tapestry5; |
| |
| /** |
| * Defines a field within a form. Fields have a <a href="http://www.w3.org/TR/html4/interact/forms.html#control-name">control |
| * name</a> that is used when rendering and, later, when the form is submitted, to identify the query parameter. |
| * <p/> |
| * Timing is important, as components may render multiple times, due to looping and other factors. Generally, a |
| * component's {@link #getControlName()} will only be accurate after it has rendered. In some cases, when generating |
| * JavaScript for example, it is necessary to {@linkplain org.apache.tapestry5.services.Heartbeat#defer(Runnable) wait |
| * until the end of the current Heartbeat} to ensure that all components have had their chance to render. |
| */ |
| public interface Field extends ClientElement |
| { |
| /** |
| * Returns the value used as the name attribute of the rendered element. This value will be unique within an |
| * enclosing form, even if the same component renders multiple times. |
| * |
| * @see org.apache.tapestry5.services.FormSupport#allocateControlName(String) |
| */ |
| String getControlName(); |
| |
| /** |
| * Returns a user presentable (localized) label for the field, which may be used inside <label> elements on |
| * the client, and inside client or server-side validation error messages. |
| * |
| * @return the label |
| * @see org.apache.tapestry5.corelib.components.Label |
| */ |
| String getLabel(); |
| |
| /** |
| * Returns true if the field is disabled; A disabled field will render a disabled attribute so that it is |
| * non-responsive on the client (at least, until its disabled status is changed on the client using JavaScript). A |
| * disabled field will ignore any value passed up in a form submit request. Care must be taken if the disabled |
| * status of a field can change between the time the field is rendered and the time the enclosing form is |
| * submitted. |
| */ |
| boolean isDisabled(); |
| |
| /** |
| * Returns true if this field required (as per {@link org.apache.tapestry5.FieldValidator#isRequired()}). |
| * |
| * @return true if a non-blank value is required for the field |
| */ |
| boolean isRequired(); |
| } |