blueprint/blueprint-spring/src/main/java/org/apache/aries/blueprint/spring/SpringApplicationContext.java

/**
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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.apache.aries.blueprint.spring;

import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.NoSuchElementException;

import org.apache.aries.blueprint.services.ExtendedBlueprintContainer;
import org.osgi.framework.Bundle;
import org.osgi.framework.wiring.BundleWiring;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.context.support.AbstractApplicationContext;

public class SpringApplicationContext extends AbstractApplicationContext {

    private final ExtendedBlueprintContainer container;
    private final DefaultListableBeanFactory beanFactory;
    private final List<ClassLoader> parentClassLoaders = new ArrayList<ClassLoader>();

    public SpringApplicationContext(ExtendedBlueprintContainer container) {
        this.container = container;
        parentClassLoaders.add(container.getClassLoader());
        setClassLoader(new ClassLoader() {
            @Override
            public Class<?> loadClass(String name) throws ClassNotFoundException {
                for (ClassLoader cl : parentClassLoaders) {
                    try {
                        return cl.loadClass(name);
                    } catch (ClassNotFoundException e) {
                        // Ignore
                    }
                }
                throw new ClassNotFoundException(name);
            }

            @Override
            public URL getResource(String name) {
                for (ClassLoader cl : parentClassLoaders) {
                    URL url =  cl.getResource(name);
                    if (url != null) {
                        return url;
                    }
                }
                return null;
            }

            @Override
            public Enumeration<URL> getResources(String name) throws IOException {
                final Enumeration<URL>[] enums = (Enumeration<URL>[]) new Enumeration<?>[parentClassLoaders.size()];
                for (int i = 0; i < enums.length; i++) {
                    enums[i] = parentClassLoaders.get(i).getResources(name);
                }
                return new Enumeration<URL>() {
                    private int index = 0;
                    @Override
                    public boolean hasMoreElements() {
                        return next();
                    }
                    @Override
                    public URL nextElement() {
                        if (!this.next()) {
                            throw new NoSuchElementException();
                        } else {
                            return enums[this.index].nextElement();
                        }
                    }
                    private boolean next() {
                        while(this.index < enums.length) {
                            if (enums[this.index] != null && enums[this.index].hasMoreElements()) {
                                return true;
                            }
                            ++this.index;
                        }
                        return false;
                    }
                };
            }
        });
        this.beanFactory = new BlueprintBeanFactory(container, this);
        prepareBeanFactory(beanFactory);
        prepareRefresh();
    }

    public void process() {
        // Invoke factory processors registered as beans in the context.
        invokeBeanFactoryPostProcessors(beanFactory);
        // Register bean processors that intercept bean creation.
        registerBeanPostProcessors(beanFactory);
    }

    @Override
    protected void refreshBeanFactory() throws BeansException, IllegalStateException {
    }

    @Override
    protected void closeBeanFactory() {
    }

    @Override
    public DefaultListableBeanFactory getBeanFactory() throws IllegalStateException {
        return beanFactory;
    }

    public void addSourceBundle(Bundle bundle) {
        // This should always be not null, but we want to support unit testing
        if (bundle != null) {
            parentClassLoaders.add(bundle.adapt(BundleWiring.class).getClassLoader());
        }
    }

}