net.sourceforge.hypo.inject.resolver.DefaultTypeSpringBeanResolver.java Source code

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Here is the source code for net.sourceforge.hypo.inject.resolver.DefaultTypeSpringBeanResolver.java

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/*
 * Copyright 2008 Alasdair Gilmour 
 * 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 net.sourceforge.hypo.inject.resolver;

import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import net.sourceforge.hypo.inject.dependency.Dependency;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

/**
 * A Spring-aware DependencyResolver that looks up the Spring ApplicationContext to find the single bean
 * which has the same type as or is a subclass of the Dependency's type
 */
public class DefaultTypeSpringBeanResolver extends AbstractDependencyResolver implements ApplicationContextAware {
    private static Logger log = Logger.getLogger(DefaultTypeSpringBeanResolver.class.getCanonicalName());

    private ApplicationContext applicationContext;

    /**
     * Performs injection by looking up the Spring ApplicationContext to find the single bean
     * which has the same type as or is a subclass of the Inject's type. 
     * @param dep the Dependency to be injected
     * @param target the object which is to have the member injected
     * @return true if a single matching bean existed in the context; false if no suitable 
     * bean was found
     * @throws RuntimeException if more than one bean in the Spring ApplicationContext matched
     * the Dependency
     */
    public ResolutionResult doResolve(Dependency dep, Object target) {
        Class<?> type = dep.getType();
        Map<?, ?> map = BeanFactoryUtils.beansOfTypeIncludingAncestors(applicationContext, type);
        if (map.size() < 1) {
            if (log.isLoggable(Level.FINE))
                log.fine("No beans of required type found for dependency " + dep + ". Skipping.");
        } else if (map.size() > 1) {
            throw new RuntimeException("Multiple beans of required type " + type + " found. Aborting.");
        } else {
            Object bean = map.values().iterator().next();
            if (log.isLoggable(Level.FINE))
                log.fine("Found bean [" + bean + "] to inject for dependency " + dep + ".");
            return ResolutionResult.resolved(bean);
        }
        return ResolutionResult.couldNotResolve();
    }

    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }
}