com.npower.dm.util.DMUtil.java Source code

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Here is the source code for com.npower.dm.util.DMUtil.java

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/**
 * $Header: /home/master/nWave-DM-Common/src/com/npower/dm/util/DMUtil.java,v 1.6 2007/08/29 06:21:00 zhao Exp $
 * $Revision: 1.6 $
 * $Date: 2007/08/29 06:21:00 $
 *
 * ===============================================================================================
 * License, Version 1.1
 *
 * Copyright (c) 1994-2006 NPower Network Software Ltd.  All rights reserved.
 *
 * This SOURCE CODE FILE, which has been provided by NPower as part
 * of a NPower product for use ONLY by licensed users of the product,
 * includes CONFIDENTIAL and PROPRIETARY information of NPower.
 *
 * USE OF THIS SOFTWARE IS GOVERNED BY THE TERMS AND CONDITIONS
 * OF THE LICENSE STATEMENT AND LIMITED WARRANTY FURNISHED WITH
 * THE PRODUCT.
 *
 * IN PARTICULAR, YOU WILL INDEMNIFY AND HOLD NPower, ITS RELATED
 * COMPANIES AND ITS SUPPLIERS, HARMLESS FROM AND AGAINST ANY CLAIMS
 * OR LIABILITIES ARISING OUT OF THE USE, REPRODUCTION, OR DISTRIBUTION
 * OF YOUR PROGRAMS, INCLUDING ANY CLAIMS OR LIABILITIES ARISING OUT OF
 * OR RESULTING FROM THE USE, MODIFICATION, OR DISTRIBUTION OF PROGRAMS
 * OR FILES CREATED FROM, BASED ON, AND/OR DERIVED FROM THIS SOURCE
 * CODE FILE.
 * ===============================================================================================
 */
package com.npower.dm.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLEncoder;
import java.security.CodeSource;
import java.security.ProtectionDomain;
import java.sql.Clob;
import java.sql.SQLException;

import org.apache.commons.lang.StringUtils;

/**
 * @author Zhao DongLu
 * @version $Revision: 1.6 $ $Date: 2007/08/29 06:21:00 $
 */
public class DMUtil {

    /**
     * 
     */
    public static final String NAME_PREFIX_FOR_NO_NAME_NODE = "OTAS";

    /**
     * 
     */
    public DMUtil() {
        super();
    }

    public static void print(ClassLoader loader) {
        System.out.println("Dump classload: " + loader.toString());
        URL[] urls = getClassLoaderURLs(loader);
        for (int i = 0; urls != null && i < urls.length; i++) {
            System.out.println(urls[i].toString());
        }
        System.out.println("End of classload: " + loader.toString());
    }

    /**
     * Format a string buffer containing the Class, Interfaces, CodeSource, and
     * ClassLoader information for the given object clazz.
     * 
     * @param clazz
     *          the Class
     * @param results,
     *          the buffer to write the info to
     */
    public static void displayClassInfo(Class<?> clazz, StringBuffer results) {
        // Print out some codebase info for the ProbeHome
        ClassLoader cl = clazz.getClassLoader();
        results.append("\n" + clazz.getName() + ".ClassLoader=" + cl);
        ClassLoader parent = cl;
        while (parent != null) {
            results.append("\n.." + parent);
            URL[] urls = getClassLoaderURLs(parent);
            int length = urls != null ? urls.length : 0;
            for (int u = 0; u < length; u++) {
                results.append("\n...." + urls[u]);
            }
            if (parent != null)
                parent = parent.getParent();
        }
        CodeSource clazzCS = clazz.getProtectionDomain().getCodeSource();
        if (clazzCS != null)
            results.append("\n++++CodeSource: " + clazzCS);
        else
            results.append("\n++++Null CodeSource");
        results.append("\nImplemented Interfaces:");
        Class<?>[] ifaces = clazz.getInterfaces();
        for (int i = 0; i < ifaces.length; i++) {
            results.append("\n++" + ifaces[i]);
            ClassLoader loader = ifaces[i].getClassLoader();
            results.append("\n++++ClassLoader: " + loader);
            ProtectionDomain pd = ifaces[i].getProtectionDomain();
            CodeSource cs = pd.getCodeSource();
            if (cs != null)
                results.append("\n++++CodeSource: " + cs);
            else
                results.append("\n++++Null CodeSource");
        }
    }

    /**
     * Use reflection to access a URL[] getURLs or ULR[] getAllURLs method so that
     * non-URLClassLoader class loaders, or class loaders that override getURLs to
     * return null or empty, can provide the true classpath info.
     */
    public static URL[] getClassLoaderURLs(ClassLoader cl) {
        URL[] urls = {};
        try {
            Class<?> returnType = urls.getClass();
            Class<?>[] parameterTypes = {};
            Method getURLs = cl.getClass().getMethod("getURLs", parameterTypes);
            if (returnType.isAssignableFrom(getURLs.getReturnType())) {
                Object[] args = {};
                urls = (URL[]) getURLs.invoke(cl, args);
            }
        } catch (Exception ignore) {
        }
        return urls;
    }

    /**
     * Convert a Clob into String.
     * 
     * @param clob
     * @return
     * @throws SQLException
     * @throws IOException
     */
    public static String convertClob2String(Clob clob) throws SQLException, IOException {
        if (clob != null) {
            BufferedReader in = new BufferedReader(clob.getCharacterStream());
            String line = in.readLine();
            StringBuffer result = new StringBuffer();
            while (line != null) {
                result.append(line);
                line = in.readLine();
            }

            // Could not close the Reader, which will cause
            // a SQLException(Could not reset the Reader) when next time to call this
            // method.
            // in.close();
            return result.toString();
        }
        return null;
    }

    /**
     * Append a parameter into URL
     * @param url
     * @param parameterName
     * @param parameterValue
     * @return
     */
    public static String appendParameter(String url, String parameterName, String parameterValue) {
        StringBuffer result = new StringBuffer(url);
        if (StringUtils.isEmpty(parameterName)) {
            return result.toString();
        }
        if (url.indexOf('?') > 0) {
            result.append('&');
        } else {
            result.append('?');
        }
        result.append(parameterName);
        result.append('=');
        try {
            result.append(URLEncoder.encode(parameterValue, "UTF-8"));
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e.getMessage(), e);
        }
        return result.toString();
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        print(Thread.currentThread().getContextClassLoader());
    }

}