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.hivemind.schema.rules;
016
017import java.beans.PropertyEditor;
018import java.beans.PropertyEditorManager;
019import java.util.Map;
020
021import org.apache.hivemind.ApplicationRuntimeException;
022import org.apache.hivemind.Location;
023import org.apache.hivemind.internal.Module;
024import org.apache.hivemind.schema.Translator;
025
026/**
027 * A "smart" translator that attempts to automatically convert from string types to object or
028 * wrapper types, using {@link java.beans.PropertyEditor}s.
029 * 
030 * @author Howard Lewis Ship
031 */
032public class SmartTranslator implements Translator
033{
034    private String _default;
035
036    public SmartTranslator()
037    {
038    }
039
040    /**
041     * Initializers:
042     * <ul>
043     * <li>default: default value for empty input
044     * </ul>
045     */
046    public SmartTranslator(String initializer)
047    {
048        Map m = RuleUtils.convertInitializer(initializer);
049
050        _default = (String) m.get("default");
051    }
052
053    public Object translate(Module contributingModule, Class propertyType, String inputValue,
054            Location location)
055    {
056        // HIVEMIND-10: Inside JavaWebStart you (strangely) can't rely on
057        // a PropertyEditor for String (even though it is trivial).
058
059        if (inputValue == null)
060        {
061            if (_default == null)
062                return null;
063
064            inputValue = _default;
065        }
066
067        if (propertyType.equals(String.class) || propertyType.equals(Object.class))
068            return inputValue;
069
070        // TODO: This duplicates logic inside PropertyAdaptor.
071
072        try
073        {
074            PropertyEditor e = PropertyEditorManager.findEditor(propertyType);
075
076            if (e == null)
077                throw new ApplicationRuntimeException(RulesMessages.noPropertyEditor(propertyType),
078                        location, null);
079
080            e.setAsText(inputValue);
081
082            return e.getValue();
083        }
084        catch (Exception ex)
085        {
086            throw new ApplicationRuntimeException(RulesMessages.smartTranslatorError(
087                    inputValue,
088                    propertyType,
089                    ex), location, ex);
090
091        }
092    }
093
094}