Struts example source code file (ResourceStoreClassLoader.java)

This example Struts source code file (ResourceStoreClassLoader.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

class, class, classloader, classnotfoundexception, classnotfoundexception, log, logger, resourcestore, resourcestore, resourcestoreclassloader, string, string

The Struts ResourceStoreClassLoader.java source code

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * 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.opensymphony.xwork2.util.classloader;

import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

/**
 * class taken from Apache JCI
 */
public final class ResourceStoreClassLoader extends ClassLoader {

    private static final Logger LOG = LoggerFactory.getLogger(ResourceStoreClassLoader.class);

    private final ResourceStore[] stores;

    public ResourceStoreClassLoader(final ClassLoader pParent, final ResourceStore[] pStores) {
        super(pParent);

        stores = new ResourceStore[pStores.length];
        System.arraycopy(pStores, 0, stores, 0, stores.length);
    }

    private Class fastFindClass(final String name) {

        if (stores != null) {
            String fileName = name.replace('.', '/') + ".class";
            for (final ResourceStore store : stores) {
                final byte[] clazzBytes = store.read(fileName);
                if (clazzBytes != null) {
                    definePackage(name);
                    return defineClass(name, clazzBytes, 0, clazzBytes.length);
                }
            }
        }

        return null;
    }

    protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
        Class clazz = findLoadedClass(name);

        if (clazz == null) {
            clazz = fastFindClass(name);

            if (clazz == null) {
                final ClassLoader parent = getParent();
                if (parent != null) {
                    clazz = parent.loadClass(name);
                } else {
                    throw new ClassNotFoundException(name);
                }

            }
        }

        if (resolve) {
            resolveClass(clazz);
        }

        return clazz;
    }

    protected Class findClass(final String name) throws ClassNotFoundException {
        final Class clazz = fastFindClass(name);
        if (clazz == null) {
            throw new ClassNotFoundException(name);
        }
        return clazz;
    }

    /**
     * Define the package information associated with a class.
     *
     * @param className the class name of for which the package information
     *                  is to be determined.
     */
    protected void definePackage(String className){
        int classIndex = className.lastIndexOf('.');
        if (classIndex == -1) {
            return;
        }
        String packageName = className.substring(0, classIndex);
        if (getPackage(packageName) != null) {
            return;
        }
        definePackage(packageName, null, null, null, null, null, null, null);
    }
}