001    // Copyright 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.translator;
016    
017    import java.util.Locale;
018    
019    import org.apache.tapestry.form.FormComponentContributor;
020    import org.apache.tapestry.form.IFormComponent;
021    import org.apache.tapestry.form.ValidatableField;
022    import org.apache.tapestry.form.ValidationMessages;
023    import org.apache.tapestry.valid.ValidatorException;
024    
025    /**
026     * Interface used by {@link ValidatableField}s to both format an object as text and translate
027     * submitted text into an appropriate object for a given field.
028     * 
029     * @author Paul Ferraro
030     * @since 4.0
031     */
032    public interface Translator extends FormComponentContributor
033    {
034        /**
035         * Invoked during rendering to format an object (which may be null) into a text value (which
036         * should not be null) appropriate for the specified field.
037         * @param locale TODO
038         */
039        String format(IFormComponent field, Locale locale, Object object);
040    
041        /**
042         * Invoked during rewind to parse a submitted input value into an object suitable for the
043         * specified component.
044         * @param messages TODO
045         * 
046         * @return the parsed object
047         * @throws ValidatorException
048         *             if the specified text could not be parsed into an object.
049         */
050        Object parse(IFormComponent field, ValidationMessages messages, String value) throws ValidatorException;
051    }