001// Copyright 2013  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.tapestry5.internal.services;
016
017import org.apache.tapestry5.ValueEncoder;
018import org.apache.tapestry5.commons.services.ClassPropertyAdapter;
019import org.apache.tapestry5.commons.services.PropertyAccess;
020import org.apache.tapestry5.commons.services.PropertyAdapter;
021import org.apache.tapestry5.services.ValueEncoderSource;
022import org.apache.tapestry5.services.ValueLabelProvider;
023
024/**
025 * Provides a label from a property of the passed object.
026 * 
027 * @since 5.4
028 */
029public class PropertyValueLabelProvider implements ValueLabelProvider<Object>
030{
031    private final PropertyAccess propertyAccess;
032    private final ValueEncoderSource valueEncoderSource;
033    private final String labelProperty;
034
035    public PropertyValueLabelProvider(ValueEncoderSource valueEncoderSource,
036            PropertyAccess propertyAccess, String labelProperty)
037    {
038        this.valueEncoderSource = valueEncoderSource;
039        this.propertyAccess = propertyAccess;
040        this.labelProperty = labelProperty;
041    }
042
043    @SuppressWarnings({ "unchecked", "rawtypes" })
044    public String getLabel(Object object)
045    {
046        final ClassPropertyAdapter classPropertyAdapter = this.propertyAccess.getAdapter(object);
047
048        final PropertyAdapter propertyAdapter = classPropertyAdapter
049                .getPropertyAdapter(labelProperty);
050
051        final ValueEncoder encoder = this.valueEncoderSource.getValueEncoder(propertyAdapter
052                .getType());
053
054        final Object label = propertyAdapter.get(object);
055
056        return encoder.toClient(label);
057    }
058}