com.openteach.diamond.container.DefaultClassLoaderDelegateHook.java Source code

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Here is the source code for com.openteach.diamond.container.DefaultClassLoaderDelegateHook.java

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/**
 * Copyright 2013 openteach
 *
 *  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 com.openteach.diamond.container;

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

import org.eclipse.osgi.baseadaptor.HookConfigurator;
import org.eclipse.osgi.baseadaptor.HookRegistry;
import org.eclipse.osgi.framework.adaptor.BundleClassLoader;
import org.eclipse.osgi.framework.adaptor.BundleData;
import org.eclipse.osgi.framework.adaptor.ClassLoaderDelegateHook;

/**
 * 
 * ?????<br>
 * OSGi?<br>
 * ??OSGi
 * 
 * @author sihai
 *
 */
public class DefaultClassLoaderDelegateHook implements ClassLoaderDelegateHook, HookConfigurator {

    private static List<ClassLoader> thirdClassLoaders = new ArrayList<ClassLoader>();

    private static List<String> excludedPrefixes = null;

    static {
        String excluded = System.getProperty("com.galaxy.diamond.container.excluded.prefixes");
        if (excluded != null) {
            excludedPrefixes = Arrays.asList(excluded.split(","));
        } else {
            excludedPrefixes = new ArrayList<String>();
            //?spring,log4j,common-loggingOSGi?
            excludedPrefixes.add("org.springframework");
            excludedPrefixes.add("com.alibaba.common.lang");
            //excludedPrefixes.add("org.apache.log4j");
            //excludedPrefixes.add("org.apache.commons.logging");
        }
    }

    public static void addThirdClassLoader(ClassLoader loader) {
        thirdClassLoaders.add(loader);
    }

    public Class preFindClass(String className, BundleClassLoader classloader, BundleData data)
            throws ClassNotFoundException {
        boolean loadFromExternal = false;
        for (String prefix : excludedPrefixes) {
            if (className.startsWith(prefix)) {
                loadFromExternal = true;
                break;
            }
        }
        if (loadFromExternal) {
            for (ClassLoader thirdClassLoader : thirdClassLoaders) {
                if (thirdClassLoader != null) {
                    try {
                        return thirdClassLoader.loadClass(className);
                    } catch (ClassNotFoundException e) {
                        // IGNORE,continue find
                    }
                }
            }
        }
        return null;
    }

    public Class postFindClass(String name, BundleClassLoader classloader, BundleData data)
            throws ClassNotFoundException {
        // ??groovy??
        if ((name != null) && (name.startsWith("groovy.runtime.metaclass"))) {
            return null;
        }
        for (ClassLoader thirdClassLoader : thirdClassLoaders) {
            if (thirdClassLoader != null) {
                try {
                    return thirdClassLoader.loadClass(name);
                } catch (ClassNotFoundException e) {
                    // IGNORE,continue find
                }
            }
        }
        return null;
    }

    public URL preFindResource(String name, BundleClassLoader classloader, BundleData data)
            throws FileNotFoundException {
        for (ClassLoader thirdClassLoader : thirdClassLoaders) {
            if (thirdClassLoader != null) {
                try {
                    return thirdClassLoader.getResource(name);
                } catch (Exception e) {
                    // IGNORE
                }
            }
        }
        return null;
    }

    public URL postFindResource(String name, BundleClassLoader classloader, BundleData data)
            throws FileNotFoundException {
        return null;
    }

    public Enumeration preFindResources(String name, BundleClassLoader classloader, BundleData data)
            throws FileNotFoundException {
        for (ClassLoader thirdClassLoader : thirdClassLoaders) {
            if (thirdClassLoader != null)
                try {
                    return thirdClassLoader.getResources(name);
                } catch (IOException e) {
                    // IGNORE
                }
        }
        return null;
    }

    public Enumeration postFindResources(String name, BundleClassLoader classloader, BundleData data)
            throws FileNotFoundException {
        return null;
    }

    public String preFindLibrary(String name, BundleClassLoader classloader, BundleData data)
            throws FileNotFoundException {
        return null;
    }

    public String postFindLibrary(String name, BundleClassLoader classloader, BundleData data) {
        return null;
    }

    public void addHooks(HookRegistry registry) {
        registry.addClassLoaderDelegateHook(this);
    }
}