Glassfish example source code file (ClassFileLoaderFactory.java)

This example Glassfish source code file (ClassFileLoaderFactory.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 - Glassfish tags/keywords

classfileloader, classfileloader, classfileloaderfactory, classfileloaderfactory, could, exception, illegalargumentexception, log, logging, noi18n, noi18n, object, property, reflection, runtimeexception, string, string

The Glassfish ClassFileLoaderFactory.java source code

/*
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 *
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 *
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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
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/*
 * ClassFileLoaderFactory.java
 *
 * Created on August 24, 2004, 5:56 PM
 */

package com.sun.enterprise.tools.verifier.apiscan.classfile;

import java.lang.reflect.Constructor;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * A factory for ClassFileLoader so that we can control the creation of
 * ClassFileLoaders. More over, this factory can be dynamically configured by
 * setting the Java class name of the actual ClassFileLoader type in the system
 * property apiscan.ClassFileLoader. See newInstance() method.
 *
 * @author Sanjeeb.Sahoo@Sun.COM
 */
public class ClassFileLoaderFactory {
    private static String resourceBundleName = "com.sun.enterprise.tools.verifier.apiscan.LocalStrings";
    private static Logger logger = Logger.getLogger("apiscan.classfile", resourceBundleName); // NOI18N
    private final static String myClassName = "ClassFileLoaderFactory"; // NOI18N
    /**
     * a factory method to create ClassFileLoader instance. It decides which
     * kind of loader class to instantioate based on the class name supplied by
     * the system property ClassFileLoader. If there is no such property set, it
     * defaults to {@link BCELClassFileLoader}
     *
     * @param args Search path to be used by the ClassFileLoader. Depending on
     *             the type of the ClassFileLoader requested, the semantics of
     *             this argument varies.
     * @throws RuntimeException If it could not instantiate the loader type
     *                          requested. The actual error is wrapped in this
     *                          exception.
     */
    public static ClassFileLoader newInstance(Object[] args)
            throws RuntimeException {
        logger.entering(myClassName, "newInstance", args); // NOI18N
        String loaderClassName = System.getProperty("apiscan.ClassFileLoader");
        if (loaderClassName == null) {
            loaderClassName =
                    com.sun.enterprise.tools.verifier.apiscan.classfile.BCELClassFileLoader.class.getName();
            logger.logp(Level.FINE, myClassName, "newInstance", // NOI18N
                    "System Property apiscan.ClassFileLoader is null, so defaulting to " + // NOI18N
                    loaderClassName);
        }
        try {
            Class clazz = Class.forName(loaderClassName);
            Object o = null;
            Constructor[] constrs = clazz.getConstructors();
            for (int i = 0; i < constrs.length; ++i) {
                try {
                    o = constrs[i].newInstance(args);
                } catch (IllegalArgumentException e) {
                 //try another constr as this argument did not match the reqd types for this constr.
                }
            }
            if (o == null) throw new Exception(
                    "Could not find a suitable constructor for this argument types.");
            logger.exiting(myClassName, "<init>", o); // NOI18N
            return (ClassFileLoader) o;
        } catch (Exception e) {
            logger.log(Level.SEVERE, "com.sun.enterprise.tools.verifier.apiscan.classfile.ClassFileLoaderFactory.exception1", e);
            throw new RuntimeException("Unable to instantiate a loader.", e);
        }
    }
}