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 org.apache.hivemind.ApplicationRuntimeException;
018import org.apache.hivemind.Location;
019import org.apache.hivemind.internal.Module;
020import org.apache.hivemind.service.ObjectProvider;
021import org.apache.hivemind.util.PropertyUtils;
022
023/**
024 * {@link org.apache.hivemind.service.ObjectProvider} implementation
025 * that obtains a named property from a service.  This provider is
026 * mapped to the prefix "service-property", the service id is seperated
027 * from the property name by a colon.  Example:
028 * <code>service-property:MyService:myProperty</code>
029 *
030 * @author Howard Lewis Ship
031 */
032public class ServicePropertyObjectProvider implements ObjectProvider
033{
034
035    public Object provideObject(
036        Module contributingModule,
037        Class propertyType,
038        String locator,
039        Location location)
040    {
041        int commax = locator.indexOf(':');
042
043        if (commax < 2)
044        {
045            throw new ApplicationRuntimeException(
046                ServiceMessages.invalidServicePropertyLocator(locator),
047                location,
048                null);
049        }
050
051        String serviceId = locator.substring(0, commax);
052        String propertyName = locator.substring(commax + 1);
053
054        Object service = contributingModule.getService(serviceId, Object.class);
055
056        return PropertyUtils.read(service, propertyName);
057    }
058
059}