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    
015    package org.apache.hivemind.schema.rules;
016    
017    import java.beans.PropertyEditor;
018    import java.beans.PropertyEditorManager;
019    import java.util.Map;
020    
021    import org.apache.hivemind.ApplicationRuntimeException;
022    import org.apache.hivemind.Location;
023    import org.apache.hivemind.internal.Module;
024    import 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     */
032    public 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    }