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.service.impl;
016
017import java.util.HashMap;
018import java.util.Map;
019
020import org.apache.hivemind.ApplicationRuntimeException;
021import org.apache.hivemind.ErrorLog;
022import org.apache.hivemind.HiveMind;
023import org.apache.hivemind.Location;
024import org.apache.hivemind.internal.Module;
025import org.apache.hivemind.schema.Translator;
026import org.apache.hivemind.service.ObjectProvider;
027
028/**
029 * Implementation of the indirect translator. This translator allows the contributor, not the
030 * schema, to define where object values come from, and is fully extensible. Perhaps I'll have an
031 * inspiration and find a better name than "indirect".
032 * 
033 * @author Howard Lewis Ship
034 */
035public class ObjectTranslator implements Translator
036{
037    /** @since 1.1 */
038    private ErrorLog _errorLog;
039
040    /**
041     * Keyed on prefix, value is an {@link org.apache.hivemind.service.ObjectProvider}.
042     */
043    private Map _providers = new HashMap();
044
045    public Object translate(Module contributingModule, Class propertyType, String inputValue,
046            Location location)
047    {
048        if (HiveMind.isBlank(inputValue))
049            return null;
050
051        int colonx = inputValue.indexOf(':');
052
053        if (colonx < 1)
054        {
055            _errorLog.error(ServiceMessages.invalidProviderSelector(inputValue), null, null);
056
057            return null;
058        }
059
060        String prefix = inputValue.substring(0, colonx);
061
062        ObjectProvider provider = (ObjectProvider) _providers.get(prefix);
063
064        if (provider == null)
065        {
066            _errorLog.error(ServiceMessages.unknownProviderPrefix(prefix), location, null);
067
068            return null;
069        }
070
071        String locator = inputValue.substring(colonx + 1);
072
073        try
074        {
075            return provider.provideObject(contributingModule, propertyType, locator, location);
076        }
077        catch (Exception ex)
078        {
079            throw new ApplicationRuntimeException(ex.getMessage(), location, ex);
080        }
081
082    }
083
084    public void setContributions(Map map)
085    {
086        _providers = map;
087    }
088
089    /** @since 1.1 */
090    public void setErrorLog(ErrorLog errorLog)
091    {
092        _errorLog = errorLog;
093    }
094}