// Copyright 2008 Thiago H. de Paula Figueiredo

 //

 // 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 br.com.arsmachina.tapestrycrud.services.impl;

 import java.util.Map;

 import org.apache.tapestry5.ioc.util.StrategyRegistry;

 import br.com.arsmachina.tapestrycrud.encoder.LabelEncoder;

 import br.com.arsmachina.tapestrycrud.services.EncoderSource;

 import br.com.arsmachina.tapestrycrud.services.LabelEncoderSource;

 /**

  * {@link LabelEncoderSource} implementation.

  * 

  * @author Thiago H. de Paula Figueiredo

  */

 public class LabelEncoderSourceImpl implements LabelEncoderSource {

         final private static LabelEncoder<Object> DEFAULT_ENCODER = new ToStringEncoder();

         @SuppressWarnings("unchecked")

         final private StrategyRegistry<LabelEncoder> registry;

         final private EncoderSource encoderSource;

         /**

          * Single constructor.

          * 

          * @param registrations

          */

         @SuppressWarnings("unchecked")

         public LabelEncoderSourceImpl(Map<Class, LabelEncoder> registrations,

                         EncoderSource encoderSource) {

                 if (registrations == null) {

                         throw new IllegalArgumentException("Parameter registrations cannot be null");

                 }

                 if (encoderSource == null) {

                         throw new IllegalArgumentException("Parameter encoderSource cannot be null");

                 }

                 registry = StrategyRegistry.newInstance(LabelEncoder.class, registrations, true);

                 this.encoderSource = encoderSource;

         }

         /**

          * @see br.com.arsmachina.tapestrycrud.services.LabelEncoderSource#get(java.lang.Class)

          */

         @SuppressWarnings("unchecked")

         public <T> LabelEncoder<T> get(Class<T> clasz) {

                 LabelEncoder<T> encoder = registry.get(clasz);

                 if (encoder == null) {

                         encoder = encoderSource.get(clasz);

                 }

                 if (encoder == null) {

                         encoder = (LabelEncoder<T>) DEFAULT_ENCODER;

                 }

                 return encoder;

         }

         final private static class ToStringEncoder implements LabelEncoder<Object> {

                 public String toLabel(Object object) {

                         return object.toString();

                 }

         }

 }