environmentcheck.java

java1.6众多例子参考

/*
 * Copyright 2001-2004 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.
 */
/*
 * $Id: EnvironmentCheck.java,v 1.2.4.1 2005/09/09 07:13:59 pvedula Exp $
 */
package com.sun.org.apache.xalan.internal.xslt;

import java.io.File;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.StringTokenizer;
import java.util.Vector;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Utility class to report simple information about the environment.
 * Simplistic reporting about certain classes found in your JVM may 
 * help answer some FAQs for simple problems.
 *
 * <p>Usage-command line:  
 * <code>
 * java com.sun.org.apache.xalan.internal.xslt.EnvironmentCheck [-out outFile]
 * </code></p>
 * 
 * <p>Usage-from program:  
 * <code>
 * boolean environmentOK = 
 * (new EnvironmentCheck()).checkEnvironment(yourPrintWriter);
 * </code></p>
 *
 * <p>Usage-from stylesheet:  
 * <code><pre>
 *    &lt;?xml version="1.0"?&gt;
 *    &lt;xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"
 *        xmlns:xalan="http://xml.apache.org/xalan"
 *        exclude-result-prefixes="xalan"&gt;
 *    &lt;xsl:output indent="yes"/&gt;
 *    &lt;xsl:template match="/"&gt;
 *      &lt;xsl:copy-of select="xalan:checkEnvironment()"/&gt;
 *    &lt;/xsl:template&gt;
 *    &lt;/xsl:stylesheet&gt;
 * </pre></code></p>
 *  
 * <p>Xalan users reporting problems are encouraged to use this class 
 * to see if there are potential problems with their actual 
 * Java environment <b>before</b> reporting a bug.  Note that you 
 * should both check from the JVM/JRE's command line as well as 
 * temporarily calling checkEnvironment() directly from your code, 
 * since the classpath may differ (especially for servlets, etc).</p>
 *
 * <p>Also see http://xml.apache.org/xalan-j/faq.html</p>
 *
 * <p>Note: This class is pretty simplistic: 
 * results are not necessarily definitive nor will it find all 
 * problems related to environment setup.  Also, you should avoid 
 * calling this in deployed production code, both because it is 
 * quite slow and because it forces classes to get loaded.</p>
 *
 * <p>Note: This class explicitly has very limited compile-time 
 * dependencies to enable easy compilation and usage even when 
 * Xalan, DOM/SAX/JAXP, etc. are not present.</p>
 * 
 * <p>Note: for an improved version of this utility, please see 
 * the xml-commons' project Which utility which does the same kind 
 * of thing but in a much simpler manner.</p>
 *
 * @author [e-mail]
 * @version $Id: EnvironmentCheck.java,v 1.4 2005/08/30 10:06:03 neerajbj Exp $
 */
public class EnvironmentCheck
{

  /**
   * Command line runnability: checks for [-out outFilename] arg.
   * <p>Command line entrypoint; Sets output and calls 
   * {@link #checkEnvironment(PrintWriter)}.</p>
   * @param args command line args
   */
  public static void main(String[] args)
  {
    // Default to System.out, autoflushing
    PrintWriter sendOutputTo = new PrintWriter(System.out, true);

    // Read our simplistic input args, if supplied
    for (int i = 0; i < args.length; i++)
    {
      if ("-out".equalsIgnoreCase(args[i]))
      {
        i++;

        if (i < args.length)
        {
          try
          {
            sendOutputTo = new PrintWriter(new FileWriter(args[i], true));
          }
          catch (Exception e)
          {
            System.err.println("# WARNING: -out " + args[i] + " threw "
                               + e.toString());
          }
        }
        else
        {
          System.err.println(
            "# WARNING: -out argument should have a filename, output sent to console");
        }
      }
    }

    EnvironmentCheck app = new EnvironmentCheck();
    app.checkEnvironment(sendOutputTo);
  }

  /**
   * Programmatic entrypoint: Report on basic Java environment 
   * and CLASSPATH settings that affect Xalan.
   *
   * <p>Note that this class is not advanced enough to tell you 
   * everything about the environment that affects Xalan, and 
   * sometimes reports errors that will not actually affect 
   * Xalan's behavior.  Currently, it very simplistically 
   * checks the JVM's environment for some basic properties and 
   * logs them out; it will report a problem if it finds a setting 
   * or .jar file that is <i>likely</i> to cause problems.</p>
   *
   * <p>Advanced users can peruse the code herein to help them 
   * investigate potential environment problems found; other users 
   * may simply send the output from this tool along with any bugs 
   * they submit to help us in the debugging process.</p>
   *
   * @param pw PrintWriter to send output to; can be sent to a 
   * file that will look similar to a Properties file; defaults 
   * to System.out if null
   * @return true if your environment appears to have no major 
   * problems; false if potential environment problems found
   * @see #getEnvironmentHash()
   */
  public boolean checkEnvironment(PrintWriter pw)
  {

    // Use user-specified output writer if non-null
    if (null != pw)
      outWriter = pw;

    // Setup a hash to store various environment information in
    Hashtable hash = getEnvironmentHash();

    // Check for ERROR keys in the hashtable, and print report
    boolean environmentHasErrors = writeEnvironmentReport(hash);

    if (environmentHasErrors)
    {
      // Note: many logMsg calls have # at the start to 
      //  fake a property-file like output
      logMsg("# WARNING: Potential problems found in your environment!");
      logMsg("#    Check any 'ERROR' items above against the Xalan FAQs");
      logMsg("#    to correct potential problems with your classes/jars");
      logMsg("#    http://xml.apache.org/xalan-j/faq.html");
      if (null != outWriter)
        outWriter.flush();
      return false;
    }
    else
    {
      logMsg("# YAHOO! Your environment seems to be OK.");
      if (null != outWriter)
        outWriter.flush();
      return true;
    }
  }

  /**
   * Fill a hash with basic environment settings that affect Xalan.
   *
   * <p>Worker method called from various places.</p>
   * <p>Various system and CLASSPATH, etc. properties are put into 
   * the hash as keys with a brief description of the current state 
   * of that item as the value.  Any serious problems will be put in 
   * with a key that is prefixed with {@link #ERROR 'ERROR.'} so it
   * stands out in any resulting report; also a key with just that 
   * constant will be set as well for any error.</p>
   * <p>Note that some legitimate cases are flaged as potential 
   * errors - namely when a developer recompiles xalan.jar on their 
   * own - and even a non-error state doesn't guaruntee that 
   * everything in the environment is correct.  But this will help 
   * point out the most common classpath and system property
   * problems that we've seen.</p>   
   *
   * @return Hashtable full of useful environment info about Xalan 
   * and related system properties, etc.
   */
  public Hashtable getEnvironmentHash()
  {
    // Setup a hash to store various environment information in
    Hashtable hash = new Hashtable();

    // Call various worker methods to fill in the hash
    //  These are explicitly separate for maintenance and so 
    //  advanced users could call them standalone
    checkJAXPVersion(hash);
    checkProcessorVersion(hash);
    checkParserVersion(hash);
    checkAntVersion(hash);
    checkDOMVersion(hash);
    checkSAXVersion(hash);
    checkSystemProperties(hash);

    return hash;
  }

  /**
   * Dump a basic Xalan environment report to outWriter.  
   *
   * <p>This dumps a simple header and then each of the entries in 
   * the Hashtable to our PrintWriter; it does special processing 
   * for entries that are .jars found in the classpath.</p>
   *
   * @param h Hashtable of items to report on; presumably
   * filled in by our various check*() methods
   * @return true if your environment appears to have no major 
   * problems; false if potential environment problems found
   * @see #appendEnvironmentReport(Node, Document, Hashtable)
   * for an equivalent that appends to a Node instead
   */
  protected boolean writeEnvironmentReport(Hashtable h)
  {

    if (null == h)
    {
      logMsg("# ERROR: writeEnvironmentReport called with null Hashtable");
      return false;
    }

    boolean errors = false;

    logMsg(
      "#---- BEGIN writeEnvironmentReport($Revision: 1.4 $): Useful stuff found: ----");

    // Fake the Properties-like output
    for (Enumeration keys = h.keys(); 
         keys.hasMoreElements();
        /* no increment portion */
        )
    {
      Object key = keys.nextElement();
      String keyStr = (String) key;
      try
      {
        // Special processing for classes found..
        if (keyStr.startsWith(FOUNDCLASSES))
        {
          Vector v = (Vector) h.get(keyStr);
          errors |= logFoundJars(v, keyStr);
        }
        // ..normal processing for all other entries
        else
        {
          // Note: we could just check for the ERROR key by itself, 
          //    since we now set that, but since we have to go 
          //    through the whole hash anyway, do it this way,
          //    which is safer for maintenance
          if (keyStr.startsWith(ERROR))
          {
            errors = true;
          }
          logMsg(keyStr + "=" + h.get(keyStr));
        }
      }
      catch (Exception e)
      {
        logMsg("Reading-" + key + "= threw: " + e.toString());
      }
    }

    logMsg(
      "#----- END writeEnvironmentReport: Useful properties found: -----");

    return errors;
  }

  /** Prefixed to hash keys that signify serious problems.  */
  public static final String ERROR = "ERROR.";

  /** Added to descriptions that signify potential problems.  */
  public static final String WARNING = "WARNING.";

  /** Value for any error found.  */
  public static final String ERROR_FOUND = "At least one error was found!";

  /** Prefixed to hash keys that signify version numbers.  */
  public static final String VERSION = "version.";

  /** Prefixed to hash keys that signify .jars found in classpath.  */
  public static final String FOUNDCLASSES = "foundclasses.";

  /** Marker that a class or .jar was found.  */
  public static final String CLASS_PRESENT = "present-unknown-version";

  /** Marker that a class or .jar was not found.  */
  public static final String CLASS_NOTPRESENT = "not-present";

  /** Listing of common .jar files that include Xalan-related classes.  */
  public String[] jarNames =
  {
    "xalan.jar", "xalansamples.jar", "xalanj1compat.jar", "xalanservlet.jar",
    "serializer.jar",   // Serializer (shared between Xalan & Xerces)
    "xerces.jar",       // Xerces-J 1.x
    "xercesImpl.jar",   // Xerces-J 2.x
    "testxsl.jar", 
    "crimson.jar", 
    "lotusxsl.jar", 
    "jaxp.jar", "parser.jar", "dom.jar", "sax.jar", "xml.jar", 
    "xml-apis.jar",
    "xsltc.jar"
  };

  /**
   * Print out report of .jars found in a classpath. 
   *
   * Takes the information encoded from a checkPathForJars() 
   * call and dumps it out to our PrintWriter.
   *
   * @param v Vector of Hashtables of .jar file info
   * @param desc description to print out in header
   *
   * @return false if OK, true if any .jars were reported 
   * as having errors
   * @see #checkPathForJars(String, String[])
   */
  protected boolean logFoundJars(Vector v, String desc)
  {

    if ((null == v) || (v.size() < 1))
      return false;

    boolean errors = false;

    logMsg("#---- BEGIN Listing XML-related jars in: " + desc + " ----");

    for (int i = 0; i < v.size(); i++)
    {
      Hashtable subhash = (Hashtable) v.elementAt(i);

      for (Enumeration keys = subhash.keys(); 
           keys.hasMoreElements();
           /* no increment portion */
          )
      {
        Object key = keys.nextElement();
        String keyStr = (String) key;
        try
        {
          if (keyStr.startsWith(ERROR))
          {
            errors = true;
          }
          logMsg(keyStr + "=" + subhash.get(keyStr));

        }
        catch (Exception e)
        {
          errors = true;
          logMsg("Reading-" + key + "= threw: " + e.toString());
        }
      }
    }

    logMsg("#----- END Listing XML-related jars in: " + desc + " -----");

    return errors;
  }

  /**
   * Stylesheet extension entrypoint: Dump a basic Xalan 
   * environment report from getEnvironmentHash() to a Node.  
   * 
   * <p>Copy of writeEnvironmentReport that creates a Node suitable 
   * for other processing instead of a properties-like text output.
   * </p>
   * @param container Node to append our report to
   * @param factory Document providing createElement, etc. services
   * @param h Hash presumably from {@link #getEnvironmentHash()}
   * @see #writeEnvironmentReport(Hashtable)
   * for an equivalent that writes to a PrintWriter instead
   */
  public void appendEnvironmentReport(Node container, Document factory, Hashtable h)
  {
    if ((null == container) || (null == factory))
    {
      return;
    }
  
    try
    {
      Element envCheckNode = factory.createElement("EnvironmentCheck");
      envCheckNode.setAttribute("version", "$Revision: 1.4 $");
      container.appendChild(envCheckNode);

      if (null == h)
      {
        Element statusNode = factory.createElement("status");
        statusNode.setAttribute("result", "ERROR");
        statusNode.appendChild(factory.createTextNode("appendEnvironmentReport called with null Hashtable!"));
        envCheckNode.appendChild(statusNode);
        return;
      }

      boolean errors = false;

      Element hashNode = factory.createElement("environment");
      envCheckNode.appendChild(hashNode);