domconfigurator.java

apache的log4j源码

              return "url [" + url.toString() + "]"; 
          }
      };
      doConfigure(action, repository);
  }

  /**
     Configure log4j by reading in a log4j.dtd compliant XML
     configuration file.

  */
  public
  void doConfigure(final InputStream inputStream, LoggerRepository repository) 
                                          throws FactoryConfigurationError {
      ParseAction action = new ParseAction() {
          public Document parse(final DocumentBuilder parser) throws SAXException, IOException {
              InputSource inputSource = new InputSource(inputStream);
              inputSource.setSystemId("dummy://log4j.dtd");
              return parser.parse(inputSource);
          }
          public String toString() { 
              return "input stream [" + inputStream.toString() + "]"; 
          }
      };
      doConfigure(action, repository);
  }

  /**
     Configure log4j by reading in a log4j.dtd compliant XML
     configuration file.

  */
  public
  void doConfigure(final Reader reader, LoggerRepository repository) 
                                          throws FactoryConfigurationError {
      ParseAction action = new ParseAction() {
          public Document parse(final DocumentBuilder parser) throws SAXException, IOException {
              InputSource inputSource = new InputSource(reader);
              inputSource.setSystemId("dummy://log4j.dtd");
              return parser.parse(inputSource);
          }
          public String toString() { 
              return "reader [" + reader.toString() + "]"; 
          }
      };
    doConfigure(action, repository);
  }

  /**
     Configure log4j by reading in a log4j.dtd compliant XML
     configuration file.

  */
  protected
  void doConfigure(final InputSource inputSource, LoggerRepository repository) 
                                          throws FactoryConfigurationError {
      if (inputSource.getSystemId() == null) {
          inputSource.setSystemId("dummy://log4j.dtd");
      }
      ParseAction action = new ParseAction() {
          public Document parse(final DocumentBuilder parser) throws SAXException, IOException {
              return parser.parse(inputSource);
          }
          public String toString() { 
              return "input source [" + inputSource.toString() + "]"; 
          }
      };
      doConfigure(action, repository);
    }
    
    
  private final void doConfigure(final ParseAction action, final LoggerRepository repository)
         throws FactoryConfigurationError {
    DocumentBuilderFactory dbf = null;
    this.repository = repository;
    try { 
      LogLog.debug("System property is :"+
  	                        OptionConverter.getSystemProperty(dbfKey, 
								  null)); 
      dbf = DocumentBuilderFactory.newInstance();
      LogLog.debug("Standard DocumentBuilderFactory search succeded.");
      LogLog.debug("DocumentBuilderFactory is: "+dbf.getClass().getName());
    } catch(FactoryConfigurationError fce) {
      Exception e = fce.getException();
      LogLog.debug("Could not instantiate a DocumentBuilderFactory.", e);
      throw fce;
    }
      
    try {
      dbf.setValidating(true);

      DocumentBuilder docBuilder = dbf.newDocumentBuilder();

      docBuilder.setErrorHandler(new SAXErrorHandler());      
      docBuilder.setEntityResolver(new Log4jEntityResolver());
         
      Document doc = action.parse(docBuilder);     
      parse(doc.getDocumentElement());
    } catch (Exception e) {
      // I know this is miserable...
      LogLog.error("Could not parse "+ action.toString() + ".", e);
    }
  }

  /**
     Configure by taking in an DOM element. 
  */
  public void doConfigure(Element element, LoggerRepository repository) {
    this.repository = repository;
    parse(element);
  }

  
  /**
     A static version of {@link #doConfigure(String, LoggerRepository)}.  */
  static
  public
  void configure(String filename) throws FactoryConfigurationError {
    new DOMConfigurator().doConfigure(filename, 
				      LogManager.getLoggerRepository());
  }

  /**
     A static version of {@link #doConfigure(URL, LoggerRepository)}.
   */
  static
  public
  void configure(URL url) throws FactoryConfigurationError {
    new DOMConfigurator().doConfigure(url, LogManager.getLoggerRepository());
  }

  /**
     Used internally to configure the log4j framework by parsing a DOM
     tree of XML elements based on <a
     href="doc-files/log4j.dtd">log4j.dtd</a>.
     
  */
  protected
  void parse(Element element) {

    String rootElementName = element.getTagName();

    if (!rootElementName.equals(CONFIGURATION_TAG)) {
      if(rootElementName.equals(OLD_CONFIGURATION_TAG)) {
	LogLog.warn("The <"+OLD_CONFIGURATION_TAG+
		     "> element has been deprecated.");
	LogLog.warn("Use the <"+CONFIGURATION_TAG+"> element instead.");
      } else {
	LogLog.error("DOM element is - not a <"+CONFIGURATION_TAG+"> element.");
	return;
      }
    }


    String debugAttrib = subst(element.getAttribute(INTERNAL_DEBUG_ATTR));
      
    LogLog.debug("debug attribute= \"" + debugAttrib +"\".");
    // if the log4j.dtd is not specified in the XML file, then the
    // "debug" attribute is returned as the empty string.
    if(!debugAttrib.equals("") && !debugAttrib.equals("null")) {      
      LogLog.setInternalDebugging(OptionConverter.toBoolean(debugAttrib, true));
    } else {
      LogLog.debug("Ignoring " + INTERNAL_DEBUG_ATTR + " attribute.");
    }

      //
      //   reset repository before configuration if reset="true"
      //       on configuration element.
      //
    String resetAttrib = subst(element.getAttribute(RESET_ATTR));
    LogLog.debug("reset attribute= \"" + resetAttrib +"\".");
    if(!("".equals(resetAttrib))) {
         if (OptionConverter.toBoolean(resetAttrib, false)) {
             repository.resetConfiguration();
         }
    }



    String confDebug = subst(element.getAttribute(CONFIG_DEBUG_ATTR));
    if(!confDebug.equals("") && !confDebug.equals("null")) {      
      LogLog.warn("The \""+CONFIG_DEBUG_ATTR+"\" attribute is deprecated.");
      LogLog.warn("Use the \""+INTERNAL_DEBUG_ATTR+"\" attribute instead.");
      LogLog.setInternalDebugging(OptionConverter.toBoolean(confDebug, true));
    }

    String thresholdStr = subst(element.getAttribute(THRESHOLD_ATTR));
    LogLog.debug("Threshold =\"" + thresholdStr +"\".");
    if(!"".equals(thresholdStr) && !"null".equals(thresholdStr)) {
      repository.setThreshold(thresholdStr);
    }

    //Hashtable appenderBag = new Hashtable(11);

    /* Building Appender objects, placing them in a local namespace
       for future reference */

    // First configure each category factory under the root element.
    // Category factories need to be configured before any of
    // categories they support.
    //
    String   tagName = null;
    Element  currentElement = null;
    Node     currentNode = null;
    NodeList children = element.getChildNodes();
    final int length = children.getLength();

    for (int loop = 0; loop < length; loop++) {
      currentNode = children.item(loop);
      if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
	currentElement = (Element) currentNode;
	tagName = currentElement.getTagName();

	if (tagName.equals(CATEGORY_FACTORY_TAG) || tagName.equals(LOGGER_FACTORY_TAG)) {
	  parseCategoryFactory(currentElement);
	}
      }
    }
    
    for (int loop = 0; loop < length; loop++) {
      currentNode = children.item(loop);
      if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
	currentElement = (Element) currentNode;
	tagName = currentElement.getTagName();

	if (tagName.equals(CATEGORY) || tagName.equals(LOGGER)) {
	  parseCategory(currentElement);
	} else if (tagName.equals(ROOT_TAG)) {
	  parseRoot(currentElement);
	} else if(tagName.equals(RENDERER_TAG)) {
	  parseRenderer(currentElement);
	} else if (!(tagName.equals(APPENDER_TAG)
            || tagName.equals(CATEGORY_FACTORY_TAG)
            || tagName.equals(LOGGER_FACTORY_TAG))) {
        quietParseUnrecognizedElement(repository, currentElement, props);
    }
      }
    }
  }

  
  protected
  String subst(final String value) {
      return subst(value, props);
  }

    /**
     * Substitutes property value for any references in expression.
     *
     * @param value value from configuration file, may contain
     *              literal text, property references or both
     * @param props properties.
     * @return evaluated expression, may still contain expressions
     *         if unable to expand.
     * @since 1.2.15
     */
    public static String subst(final String value, final Properties props) {
        try {
            return OptionConverter.substVars(value, props);
        } catch (IllegalArgumentException e) {
            LogLog.warn("Could not perform variable substitution.", e);
            return value;
        }
    }


    /**
     * Sets a parameter based from configuration file content.
     *
     * @param elem       param element, may not be null.
     * @param propSetter property setter, may not be null.
     * @param props      properties
     * @since 1.2.15
     */
    public static void setParameter(final Element elem,
                                    final PropertySetter propSetter,
                                    final Properties props) {
        String name = subst(elem.getAttribute("name"), props);
        String value = (elem.getAttribute("value"));
        value = subst(OptionConverter.convertSpecialChars(value), props);
        propSetter.setProperty(name, value);
    }

    /**
     * Creates an object and processes any nested param elements
     * but does not call activateOptions.  If the class also supports
     * UnrecognizedElementParser, the parseUnrecognizedElement method
     * will be call for any child elements other than param.
     *
     * @param element       element, may not be null.
     * @param props         properties
     * @param expectedClass interface or class expected to be implemented
     *                      by created class
     * @return created class or null.
     * @throws Exception thrown if the contain object should be abandoned.
     * @since 1.2.15
     */
    public static Object parseElement(final Element element,
                                             final Properties props,
                                             final Class expectedClass) throws Exception {
        String clazz = subst(element.getAttribute("class"), props);
        Object instance = OptionConverter.instantiateByClassName(clazz,
                expectedClass, null);

        if (instance != null) {
            PropertySetter propSetter = new PropertySetter(instance);
            NodeList children = element.getChildNodes();
            final int length = children.getLength();

            for (int loop = 0; loop < length; loop++) {
                Node currentNode = children.item(loop);
                if (currentNode.getNodeType() == Node.ELEMENT_NODE) {
                    Element currentElement = (Element) currentNode;
                    String tagName = currentElement.getTagName();
                    if (tagName.equals("param")) {
                        setParameter(currentElement, propSetter, props);
                    } else {
                         parseUnrecognizedElement(instance, currentElement, props);
                    }
                }
            }
            return instance;
        }
        return null;
    }

}


class XMLWatchdog extends FileWatchdog {

    XMLWatchdog(String filename) {
    super(filename);
  }

  /**
     Call {@link DOMConfigurator#configure(String)} with the
     <code>filename</code> to reconfigure log4j. */
  public
  void doOnChange() {
    new DOMConfigurator().doConfigure(filename, 
				      LogManager.getLoggerRepository());
  }
}