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OptionConverter.javaAPI DocApache log4j 1.2.1514553Sat Aug 25 00:09:40 BST 2007org.apache.log4j.helpers

OptionConverter

public class OptionConverter extends Object
A convenience class to convert property values to specific types.
author
Ceki Gülcü
author
Simon Kitching;
author
Anders Kristensen

Fields Summary
static String
DELIM_START
static char
DELIM_STOP
static int
DELIM_START_LEN
static int
DELIM_STOP_LEN
Constructors Summary
private OptionConverter()
OptionConverter is a static class.
Methods Summary
public static java.lang.String[]concatanateArrays(java.lang.String[] l, java.lang.String[] r)

    int len = l.length + r.length;
    String[] a = new String[len];

    System.arraycopy(l, 0, a, 0, l.length);
    System.arraycopy(r, 0, a, l.length, r.length);

    return a;
public static java.lang.StringconvertSpecialChars(java.lang.String s)

    char c;
    int len = s.length();
    StringBuffer sbuf = new StringBuffer(len);

    int i = 0;
    while(i < len) {
      c = s.charAt(i++);
      if (c == '\\") {
	c =  s.charAt(i++);
	if(c == 'n")      c = '\n";
	else if(c == 'r") c = '\r";
	else if(c == 't") c = '\t";
	else if(c == 'f") c = '\f";
	else if(c == '\b") c = '\b";
	else if(c == '\"") c = '\"";
	else if(c == '\'") c = '\'";
	else if(c == '\\") c = '\\";
      }
      sbuf.append(c);
    }
    return sbuf.toString();
public static java.lang.StringfindAndSubst(java.lang.String key, java.util.Properties props)
Find the value corresponding to key in props. Then perform variable substitution on the found value.

    String value = props.getProperty(key);
    if(value == null)
      return null;

    try {
      return substVars(value, props);
    } catch(IllegalArgumentException e) {
      LogLog.error("Bad option value ["+value+"].", e);
      return value;
    }
public static java.lang.StringgetSystemProperty(java.lang.String key, java.lang.String def)
Very similar to System.getProperty except that the {@link SecurityException} is hidden.

param
key The key to search for.
param
def The default value to return.
return
the string value of the system property, or the default value if there is no property with that key.
since
1.1

    try {
      return System.getProperty(key, def);
    } catch(Throwable e) { // MS-Java throws com.ms.security.SecurityExceptionEx
      LogLog.debug("Was not allowed to read system property \""+key+"\".");
      return def;
    }
public static java.lang.ObjectinstantiateByClassName(java.lang.String className, java.lang.Class superClass, java.lang.Object defaultValue)
Instantiate an object given a class name. Check that the className is a subclass of superClass. If that test fails or the object could not be instantiated, then defaultValue is returned.

param
className The fully qualified class name of the object to instantiate.
param
superClass The class to which the new object should belong.
param
defaultValue The object to return in case of non-fulfillment

    if(className != null) {
      try {
	Class classObj = Loader.loadClass(className);
	if(!superClass.isAssignableFrom(classObj)) {
	  LogLog.error("A \""+className+"\" object is not assignable to a \""+
		       superClass.getName() + "\" variable.");
	  LogLog.error("The class \""+ superClass.getName()+"\" was loaded by ");
	  LogLog.error("["+superClass.getClassLoader()+"] whereas object of type ");
	  LogLog.error("\"" +classObj.getName()+"\" was loaded by ["
		       +classObj.getClassLoader()+"].");
	  return defaultValue;
	}
	return classObj.newInstance();
      } catch (Exception e) {
	LogLog.error("Could not instantiate class [" + className + "].", e);
      }
    }
    return defaultValue;
public static java.lang.ObjectinstantiateByKey(java.util.Properties props, java.lang.String key, java.lang.Class superClass, java.lang.Object defaultValue)


    // Get the value of the property in string form
    String className = findAndSubst(key, props);
    if(className == null) {
      LogLog.error("Could not find value for key " + key);
      return defaultValue;
    }
    // Trim className to avoid trailing spaces that cause problems.
    return OptionConverter.instantiateByClassName(className.trim(), superClass,
						  defaultValue);
public static voidselectAndConfigure(java.net.URL url, java.lang.String clazz, org.apache.log4j.spi.LoggerRepository hierarchy)
Configure log4j given a URL.

The url must point to a file or resource which will be interpreted by a new instance of a log4j configurator.

All configurations steps are taken on the hierarchy passed as a parameter.

param
url The location of the configuration file or resource.
param
clazz The classname, of the log4j configurator which will parse the file or resource at url. This must be a subclass of {@link Configurator}, or null. If this value is null then a default configurator of {@link PropertyConfigurator} is used, unless the filename pointed to by url ends in '.xml', in which case {@link org.apache.log4j.xml.DOMConfigurator} is used.
param
hierarchy The {@link org.apache.log4j.Hierarchy} to act on.
since
1.1.4

   Configurator configurator = null;
   String filename = url.getFile();

   if(clazz == null && filename != null && filename.endsWith(".xml")) {
     clazz = "org.apache.log4j.xml.DOMConfigurator";
   }

   if(clazz != null) {
     LogLog.debug("Preferred configurator class: " + clazz);
     configurator = (Configurator) instantiateByClassName(clazz,
							  Configurator.class,
							  null);
     if(configurator == null) {
   	  LogLog.error("Could not instantiate configurator ["+clazz+"].");
   	  return;
     }
   } else {
     configurator = new PropertyConfigurator();
   }

   configurator.doConfigure(url, hierarchy);
public static java.lang.StringsubstVars(java.lang.String val, java.util.Properties props)
Perform variable substitution in string val from the values of keys found in the system propeties.

The variable substitution delimeters are ${ and }.

For example, if the System properties contains "key=value", then the call 

String s = OptionConverter.substituteVars("Value of key is ${key}.");
will set the variable s to "Value of key is value.".

If no value could be found for the specified key, then the props parameter is searched, if the value could not be found there, then substitution defaults to the empty string.

For example, if system propeties contains no value for the key "inexistentKey", then the call 

String s = OptionConverter.subsVars("Value of inexistentKey is [${inexistentKey}]");
will set s to "Value of inexistentKey is []"

An {@link java.lang.IllegalArgumentException} is thrown if val contains a start delimeter "${" which is not balanced by a stop delimeter "}".

Author Avy Sharell

param
val The string on which variable substitution is performed.
throws
IllegalArgumentException if val is malformed.


    StringBuffer sbuf = new StringBuffer();

    int i = 0;
    int j, k;

    while(true) {
      j=val.indexOf(DELIM_START, i);
      if(j == -1) {
	// no more variables
	if(i==0) { // this is a simple string
	  return val;
	} else { // add the tail string which contails no variables and return the result.
	  sbuf.append(val.substring(i, val.length()));
	  return sbuf.toString();
	}
      } else {
	sbuf.append(val.substring(i, j));
	k = val.indexOf(DELIM_STOP, j);
	if(k == -1) {
	  throw new IllegalArgumentException('""+val+
		      "\" has no closing brace. Opening brace at position " + j
					     + '.");
	} else {
	  j += DELIM_START_LEN;
	  String key = val.substring(j, k);
	  // first try in System properties
	  String replacement = getSystemProperty(key, null);
	  // then try props parameter
	  if(replacement == null && props != null) {
	    replacement =  props.getProperty(key);
	  }

	  if(replacement != null) {
	    // Do variable substitution on the replacement string
	    // such that we can solve "Hello ${x2}" as "Hello p1" 
            // the where the properties are
	    // x1=p1
            // x2=${x1}
	    String recursiveReplacement = substVars(replacement, props);
	    sbuf.append(recursiveReplacement);
	  }
	  i = k + DELIM_STOP_LEN;
	}
      }
    }
public static booleantoBoolean(java.lang.String value, boolean dEfault)
If value is "true", then true is returned. If value is "false", then true is returned. Otherwise, default is returned.

Case of value is unimportant.

    if(value == null)
      return dEfault;
    String trimmedVal = value.trim();
    if("true".equalsIgnoreCase(trimmedVal))
      return true;
    if("false".equalsIgnoreCase(trimmedVal))
      return false;
    return dEfault;
public static longtoFileSize(java.lang.String value, long dEfault)

    if(value == null)
      return dEfault;

    String s = value.trim().toUpperCase();
    long multiplier = 1;
    int index;

    if((index = s.indexOf("KB")) != -1) {
      multiplier = 1024;
      s = s.substring(0, index);
    }
    else if((index = s.indexOf("MB")) != -1) {
      multiplier = 1024*1024;
      s = s.substring(0, index);
    }
    else if((index = s.indexOf("GB")) != -1) {
      multiplier = 1024*1024*1024;
      s = s.substring(0, index);
    }
    if(s != null) {
      try {
	return Long.valueOf(s).longValue() * multiplier;
      }
      catch (NumberFormatException e) {
	LogLog.error("[" + s + "] is not in proper int form.");
	LogLog.error("[" + value + "] not in expected format.", e);
      }
    }
    return dEfault;
public static inttoInt(java.lang.String value, int dEfault)

    if(value != null) {
      String s = value.trim();
      try {
	return Integer.valueOf(s).intValue();
      }
      catch (NumberFormatException e) {
	 LogLog.error("[" + s + "] is not in proper int form.");
	e.printStackTrace();
      }
    }
    return dEfault;
public static org.apache.log4j.LeveltoLevel(java.lang.String value, org.apache.log4j.Level defaultValue)
Converts a standard or custom priority level to a Level object.

If value is of form "level#classname", then the specified class' toLevel method is called to process the specified level string; if no '#' character is present, then the default {@link org.apache.log4j.Level} class is used to process the level value.

As a special case, if the value parameter is equal to the string "NULL", then the value null will be returned.

If any error occurs while converting the value to a level, the defaultValue parameter, which may be null, is returned.

Case of value is insignificant for the level level, but is significant for the class name part, if present.

since
1.1

    if(value == null)
      return defaultValue;
      
    value = value.trim();

    int hashIndex = value.indexOf('#");
    if (hashIndex == -1) {
      if("NULL".equalsIgnoreCase(value)) {
	return null;
      } else {
	// no class name specified : use standard Level class
	return(Level) Level.toLevel(value, defaultValue);
      }
    }

    Level result = defaultValue;

    String clazz = value.substring(hashIndex+1);
    String levelName = value.substring(0, hashIndex);

    // This is degenerate case but you never know.
    if("NULL".equalsIgnoreCase(levelName)) {
	return null;
    }

    LogLog.debug("toLevel" + ":class=[" + clazz + "]"
		 + ":pri=[" + levelName + "]");

    try {
      Class customLevel = Loader.loadClass(clazz);

      // get a ref to the specified class' static method
      // toLevel(String, org.apache.log4j.Level)
      Class[] paramTypes = new Class[] { String.class,
					 org.apache.log4j.Level.class
                                       };
      java.lang.reflect.Method toLevelMethod =
                      customLevel.getMethod("toLevel", paramTypes);

      // now call the toLevel method, passing level string + default
      Object[] params = new Object[] {levelName, defaultValue};
      Object o = toLevelMethod.invoke(null, params);

      result = (Level) o;
    } catch(ClassNotFoundException e) {
      LogLog.warn("custom level class [" + clazz + "] not found.");
    } catch(NoSuchMethodException e) {
      LogLog.warn("custom level class [" + clazz + "]"
        + " does not have a class function toLevel(String, Level)", e);
    } catch(java.lang.reflect.InvocationTargetException e) {
      LogLog.warn("custom level class [" + clazz + "]"
		   + " could not be instantiated", e);
    } catch(ClassCastException e) {
      LogLog.warn("class [" + clazz
        + "] is not a subclass of org.apache.log4j.Level", e);
    } catch(IllegalAccessException e) {
      LogLog.warn("class ["+clazz+
		   "] cannot be instantiated due to access restrictions", e);
    } catch(Exception e) {
      LogLog.warn("class ["+clazz+"], level ["+levelName+
		   "] conversion failed.", e);
    }
    return result;