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Java > Open Source Codes > org > apache > tapestry > valid > IFieldTracking


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.valid;
16
17 import org.apache.tapestry.IRender;
18 import org.apache.tapestry.form.IFormComponent;
19
20 /**
21  * Defines the interface for an object that tracks input fields. This interface is now poorly named,
22  * in that it tracks errors that may <em>not</em> be associated with a specific field.
23  * <p>
24  * For each field, a flag is stored indicating if the field is, in fact, in error. The input
25  * supplied by the client is stored so that if the form is re-rendered (as is typically done when
26  * there are input errors), the value entered by the user can be displayed back to the user. An
27  * error message renderer is stored; this is an object that can render the error message (it is
28  * usually a {@link org.apache.tapestry.valid.RenderString}&nbsp;wrapper around a simple string).
29  *
30  * @author Howard Lewis Ship
31  * @since 1.0.8
32  */
33
34 public interface IFieldTracking
35 {
36     /**
37      * Returns true if the field is in error (that is, if it has an error message
38      * {@link #getErrorRenderer() renderer}.
39      */
40
41     public boolean isInError();
42
43     /**
44      * Returns the field component. This may return null if the error is not associated with any
45      * particular field. Note: may return null after the field tracking object is serialized and
46      * deserialized (the underlying component reference is transient); this metehod is primarily
47      * used for testing.
48      */
49
50     public IFormComponent getComponent();
51
52     /**
53      * Returns an object that will render the error message. The renderer <em>must</em> implement
54      * a simple <code>toString()</code> that does not produce markup, but is a simple message.
55      *
56      * @see ValidatorException#ValidatorException(String, IRender, ValidationConstraint)
57      * @since 1.0.9
58      */
59
60     public IRender getErrorRenderer();
61
62     /**
63      * Returns the invalid input recorded for the field. This is stored so that, on a subsequent
64      * render, the smae invalid input can be presented to the client to be corrected.
65      */
66
67     public String JavaDoc getInput();
68
69     /**
70      * Returns the name of the field, that is, the name assigned by the form (this will differ from
71      * the component's id when any kind of looping operation is in effect).
72      */
73
74     public String JavaDoc getFieldName();
75
76     /**
77      * Returns the validation constraint that was violated by the input. This may be null if the
78      * constraint isn't known.
79      */
80
81     public ValidationConstraint getConstraint();
82 }
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