001// Copyright 2004, 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
015package org.apache.tapestry.coerce;
016
017import java.util.Iterator;
018import java.util.List;
019
020import org.apache.hivemind.lib.util.StrategyRegistry;
021import org.apache.hivemind.lib.util.StrategyRegistryImpl;
022
023/**
024 * A service implementation that works around an
025 * {@link org.apache.hivemind.lib.util.StrategyRegistry}. The registry is contructed from a
026 * configuration that follows the <code>tapestry.coerce.Converters</code> schema (a List of
027 * {@link org.apache.tapestry.coerce.TypeConverterContribution}plus an additional converter for
028 * nulls.
029 * 
030 * @author Howard M. Lewis Ship
031 * @since 4.0
032 */
033public final class TypeConverterWrapper implements TypeConverter
034{
035    private StrategyRegistry _registry = new StrategyRegistryImpl();
036
037    private List _contributions;
038
039    private TypeConverter _nullConverter;
040
041    public void initializeService()
042    {
043        Iterator i = _contributions.iterator();
044
045        while (i.hasNext())
046        {
047            TypeConverterContribution c = (TypeConverterContribution) i.next();
048
049            _registry.register(c.getSubjectClass(), c.getConverter());
050        }
051    }
052
053    public Object convertValue(Object value)
054    {
055        if (value == null)
056        {
057            if (_nullConverter == null)
058                return null;
059
060            return _nullConverter.convertValue(null);
061        }
062
063        TypeConverter delegate = (TypeConverter) _registry.getStrategy(value.getClass());
064
065        return delegate.convertValue(value);
066    }
067
068    /**
069     * Sets the List of {@link org.apache.tapestry.coerce.TypeConverterContribution}s.
070     */
071
072    public void setContributions(List contributions)
073    {
074        _contributions = contributions;
075    }
076
077    /**
078     * Sets the converter used to convert null.
079     */
080
081    public void setNullConverter(TypeConverter nullConverter)
082    {
083        _nullConverter = nullConverter;
084    }
085}