    001    // Copyright 2007, 2008 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.tapestry5.services;
    016
    017    import org.apache.tapestry5.FieldValidator;
    018    import org.apache.tapestry5.ioc.AnnotationProvider;
    019    import org.apache.tapestry5.ioc.annotations.UsesOrderedConfiguration;
    020
    021    import java.util.List;
    022
    023    /**
    024     * Invoked to generate a list of validation constraint strings for a property. This typically involves scanning the
    025     * property for annotations or naming conventions that confer the desired validation. The constraint strings are
    026     * ultimately handed to {@link FieldValidatorSource#createValidator(org.apache.tapestry5.Field, String, String, String,
    027     * org.apache.tapestry5.ioc.Messages, java.util.Locale)}.
    028     */
    029    @UsesOrderedConfiguration(ValidationConstraintGenerator.class)
    030    public interface ValidationConstraintGenerator
    031    {
    032        /**
    033         * For a given property, identify all the approprite validation constraints. Each returned value is the name of a
    034         * validator (i.e., "required") or a validator name and configuration (i.e., "minlength=5"). These contraints are
    035         * exactly the individual terms in a {@link FieldValidatorSource#createValidators(org.apache.tapestry5.Field,
    036         * String) validate specification}. These will ultimately be used to create {@link FieldValidator}s for the field
    037         * that edits the property.
    038         *
    039         * @param propertyType       the type of the property for which constraints are needed
    040         * @param annotationProvider provides access to any annotations concerning the property (for implementations that
    041         *                           are based on analysis of property annotations)
    042         * @return a list of constraints
    043         * @see FieldValidatorSource
    044         */
    045        List<String> buildConstraints(Class propertyType, AnnotationProvider annotationProvider);
    046    }