01: // Copyright 2006, 2007 The Apache Software Foundation
02: //
03: // Licensed under the Apache License, Version 2.0 (the "License");
04: // you may not use this file except in compliance with the License.
05: // You may obtain a copy of the License at
06: //
07: // http://www.apache.org/licenses/LICENSE-2.0
08: //
09: // 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;
16:
17: /**
18: * Responsible for validation of a single field.
19: *
20: * @param <T>
21: * @see Validator
22: */
23: public interface FieldValidator<T> {
24: /**
25: * Invoked after the client-submitted value has been {@link Translator translated} to check that
26: * the value conforms to expectations (often, in terms of minimum or maximum value). If and only
27: * if the value is approved by all Validators is the value applied by the field.
28: *
29: * @param value
30: * the translated value supplied by the user
31: * @throws ValidationException
32: * if the value violates the constraint
33: */
34: void validate(T value) throws ValidationException;
35:
36: /**
37: * Invokes
38: * {@link Validator#render(Field, Object, org.apache.tapestry.ioc.MessageFormatter, MarkupWriter, PageRenderSupport)}.
39: *
40: * @param writer
41: */
42: void render(MarkupWriter writer);
43: }
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