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