ConnectorClassLoaderServiceImpl.java

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package com.sun.appserv.connectors.internal.api;

import org.glassfish.internal.api.*;
import org.jvnet.hk2.annotations.Service;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.*;
import java.util.logging.Logger;
import java.util.logging.Level;

import com.sun.logging.LogDomains;

import javax.inject.Inject;
import javax.inject.Provider;

/**
 * We support two policies:
 * 1. All standalone RARs are available to all other applications. This is the
 * Java EE 5 specific behavior.
 * 2. An application has visbility to only those standalone RARs that it
 * depends on. This is the new behavior defined in Java EE 6 as well as
 * JCA 1.6 spec. 
 *
 * @author Sanjeeb.Sahoo@Sun.COM
 */
@Service
public class ConnectorClassLoaderServiceImpl implements ConnectorClassLoaderService {

    /**
     * This class loader is used when we have just a single connector
     * class loader for all applications. In other words, we make every
     * standalone RARs available to all applications.
     */
    private volatile DelegatingClassLoader globalConnectorCL;

    @Inject
    private AppSpecificConnectorClassLoaderUtil appsSpecificCCLUtil;

    @Inject
    private Provider<ClassLoaderHierarchy> classLoaderHierarchyProvider;

    private Logger logger = LogDomains.getLogger(ConnectorClassLoaderServiceImpl.class, LogDomains.RSR_LOGGER);


    /**
     * provides connector-class-loader for the specified application
     * If application is null, global connector class loader will be provided
     * @param appName application-name
     * @return class-loader
     */
    public DelegatingClassLoader getConnectorClassLoader(String appName) {
        DelegatingClassLoader loader = null;

       // We do not have dependency on common-class-loader explicitly
       // and also cannot initialize globalConnectorCL during postConstruct via ClassLoaderHierarchy
       // which will result in circular dependency injection between kernel and connector module
       // Hence initializing globalConnectorCL lazily
        if (globalConnectorCL == null) {
            synchronized (ConnectorClassLoaderServiceImpl.class) {
                if (globalConnectorCL == null) {
                    //[parent is assumed to be common-class-loader in ConnectorClassLoaderUtil.createRARClassLoader() also]
                    final ClassLoader parent = getCommonClassLoader();
                    globalConnectorCL = AccessController.doPrivileged(new PrivilegedAction<DelegatingClassLoader>() {
                        public DelegatingClassLoader run() {
                            DelegatingClassLoader dcl = new DelegatingClassLoader(parent);
                            for (DelegatingClassLoader.ClassFinder cf : appsSpecificCCLUtil.getSystemRARClassLoaders()) {
                                dcl.addDelegate(cf);
                            }
                            return dcl;
                        }
                    });

                    for (DelegatingClassLoader.ClassFinder cf : appsSpecificCCLUtil.getSystemRARClassLoaders()) {
                        globalConnectorCL.addDelegate(cf);
                    }
                }
            }
        }
        if (hasGlobalAccessForRARs(appName)) {
            assert (globalConnectorCL != null);
            loader = globalConnectorCL;
        } else {
            appsSpecificCCLUtil.detectReferredRARs(appName);
            loader = createConnectorClassLoaderForApplication(appName);
        }
        return loader;
    }

    private boolean hasGlobalAccessForRARs(String appName) {
        return appName == null || appsSpecificCCLUtil.useGlobalConnectorClassLoader() ||
                appsSpecificCCLUtil.getRequiredResourceAdapters(appName).contains
                        (ConnectorConstants.RAR_VISIBILITY_GLOBAL_ACCESS);
    }

    private ClassLoader getCommonClassLoader(){
        return classLoaderHierarchyProvider.get().getCommonClassLoader();
    }

    private DelegatingClassLoader createConnectorClassLoaderForApplication(String appName){

        DelegatingClassLoader appSpecificConnectorClassLoader =
                new DelegatingClassLoader(getCommonClassLoader());

        //add system ra classloaders
        for(DelegatingClassLoader.ClassFinder cf : appsSpecificCCLUtil.getSystemRARClassLoaders()){
            appSpecificConnectorClassLoader.addDelegate(cf);
        }
        
        for(String raName : appsSpecificCCLUtil.getRARsReferredByApplication(appName)){
            addRarClassLoader(appName, appSpecificConnectorClassLoader, raName);
        }

        for(String raName : appsSpecificCCLUtil.getRequiredResourceAdapters(appName)){
            addRarClassLoader(appName, appSpecificConnectorClassLoader, raName);
        }
        return appSpecificConnectorClassLoader;
    }

    private void addRarClassLoader(String appName, DelegatingClassLoader appSpecificConnectorClassLoader, 
                                   String raName) {
        if(logger.isLoggable(Level.FINEST)){
                logger.finest("raName for app [ "+appName+" ] : " + raName);
        }
        DelegatingClassLoader.ClassFinder cf = getClassFinder(raName);

        if(cf != null){
            appSpecificConnectorClassLoader.addDelegate(cf);
        }else{
            //not possible
/*          TODO V3
            if(!ConnectorsUtil.isEmbedded(appName, raName)){
                throw new IllegalStateException("RAR Classloader of RAR [ "+raName+" ] not found for " +
                    "application [ "+appName+" ]");
            }
*/
        }
    }

    private DelegatingClassLoader.ClassFinder getClassFinder(String raName) {
        List<DelegatingClassLoader.ClassFinder> delegates = globalConnectorCL.getDelegates();
        DelegatingClassLoader.ClassFinder classFinder = null;
        for(DelegatingClassLoader.ClassFinder cf : delegates){
            if(raName.equals(((ConnectorClassFinder)cf).getResourceAdapterName())){
                classFinder = cf;
                break;
            }
        }
        return classFinder;
    }

}