org.apache.logging.log4j.core.util

Class OptionConverter

java.lang.Object

org.apache.logging.log4j.core.util.OptionConverter

public final class OptionConverter
extends Object

A convenience class to convert property values to specific types.

Method Summary

Modifier and Type	Method and Description
static String[]	concatenateArrays(String[] l, String[] r)
static String	convertSpecialChars(String s)
static String	findAndSubst(String key, Properties props) Find the value corresponding to key in props.
static Object	instantiateByClassName(String className, Class<?> superClass, Object defaultValue) Instantiate an object given a class name.
static Object	instantiateByKey(Properties props, String key, Class<?> superClass, Object defaultValue)
static String	substVars(String val, Properties props) Perform variable substitution in string val from the values of keys found in the system propeties.
static boolean	toBoolean(String value, boolean defaultValue) If value is "true", then true is returned.
static long	toFileSize(String value, long defaultValue)
static int	toInt(String value, int defaultValue) Convert the String value to an int.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

concatenateArrays

public static String[] concatenateArrays(String[] l,
                                         String[] r)

convertSpecialChars

public static String convertSpecialChars(String s)

instantiateByKey

public static Object instantiateByKey(Properties props,
                                      String key,
                                      Class<?> superClass,
                                      Object defaultValue)

toBoolean

public static boolean toBoolean(String value,
                                boolean defaultValue)

If value is "true", then true is returned. If value is "false", then false is returned. Otherwise, default is returned.

Case of value is unimportant.

Parameters:

value - The value to convert.

defaultValue - The default value.

Returns:

true or false, depending on the value and/or default.

toInt

public static int toInt(String value,
                        int defaultValue)

Convert the String value to an int.

Parameters:

value - The value as a String.

defaultValue - The default value.

Returns:

The value as an int.

toFileSize

public static long toFileSize(String value,
                              long defaultValue)

Parameters:

value - The size of the file as a String.

defaultValue - The default value.

Returns:

The size of the file as a long.

findAndSubst

public static String findAndSubst(String key,
                                  Properties props)

Find the value corresponding to key in props. Then perform variable substitution on the found value.

Parameters:

key - The key to locate.

props - The properties.

Returns:

The String after substitution.

instantiateByClassName

public static Object instantiateByClassName(String className,
                                            Class<?> superClass,
                                            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.

Parameters:

className - The fully qualified class name of the object to instantiate.

superClass - The class to which the new object should belong.

defaultValue - The object to return in case of non-fulfillment

Returns:

The created object.

substVars

public static String substVars(String val,
                               Properties props)
                        throws IllegalArgumentException

Perform variable substitution in string val from the values of keys found in the system propeties.

The variable substitution delimiters 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 properties 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 IllegalArgumentException is thrown if val contains a start delimeter "${" which is not balanced by a stop delimeter "}".

Parameters:

val - The string on which variable substitution is performed.

props - The properties to use for substitution.

Returns:

The String after substitution.

Throws:

IllegalArgumentException - if val is malformed.