ArtistTypeConverter.java

/*
 * Copyright 2014 Rick Grashel.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.sourceforge.stripes.examples.rockandroll;

import java.util.Collection;
import java.util.Locale;
import net.sourceforge.stripes.validation.SimpleError;
import net.sourceforge.stripes.validation.TypeConverter;
import net.sourceforge.stripes.validation.ValidationError;

/**
 * This is a type converter for Artist objects.
 */
public class ArtistTypeConverter implements TypeConverter< Artist> {

    @Override
    public void setLocale(Locale locale) {
    }

    /**
     * Takes the passed identifier and tries to look up a corresponding Artist
     * in the datastore and return it.
     *
     * @param artistIdentifier
     * @param targetType
     * @param errors
     * @return
     */
    @Override
    public Artist convert(String artistIdentifier,
            Class<? extends Artist> targetType,
            Collection<ValidationError> errors) {
        // If no identifier is passed, just return null.
        if (artistIdentifier == null) {
            return null;
        }

        // First, try to retrieve the artist by name
        Artist artist = Datastore.getArtistByName(artistIdentifier);

        // If artist is null then try to look up by ID
        if (artist == null) {
            try {
                artist = Datastore.getArtistById(Long.parseLong(artistIdentifier));
            } catch (NumberFormatException nfe) {
                // We don't care about this.  It is the same result.
            }

            // If the artist is not found by the TypeConverter, then throw and error.
            if (artist == null) {
                errors.add(new SimpleError("Unable to find artist by identifier passed => " + artistIdentifier));
            }
        }

        return artist;
    }
}