org.wamblee.system.spring.RequiredServiceBean Maven / Gradle / Ivy

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/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 
package org.wamblee.system.spring;

import org.springframework.beans.factory.FactoryBean;

import org.wamblee.system.core.RequiredInterface;
import org.wamblee.system.core.SystemAssemblyException;

import java.util.List;

/**
 * Bean which adds a service required by the spring component to the application
 * context so that other spring beans can use it.
 * 
 * @author Erik Brakkee
 */
class RequiredServiceBean implements FactoryBean {
    private RequiredInterface required;

    /**
     * Constructs the bean.
     * 
     * @param aId
     *            Id of the bean in the service registry.
     */
    public RequiredServiceBean(String aId) {
        List requiredInterfaces = SpringComponent.THIS.get()
            .getRequiredInterfaces();

        for (RequiredInterface intf : requiredInterfaces) {
            if (intf.getName().equals(aId)) {
                required = intf;

                return;
            }
        }

        throw new SystemAssemblyException(
            "Cannot resolve required component '" + aId + "'");
    }

    @Override
    public Object getObject() throws Exception {
        return SpringComponent.SCOPE.get().getInterfaceImplementation(
            required.getProvider(), Object.class);
    }

    @Override
    public Class getObjectType() {
        return null;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }
}