Package org.apache.commons.configuration2.convert

Class LegacyListDelimiterHandler

java.lang.Object
org.apache.commons.configuration2.convert.AbstractListDelimiterHandler
org.apache.commons.configuration2.convert.LegacyListDelimiterHandler
All Implemented Interfaces:
ListDelimiterHandler
public class LegacyListDelimiterHandler extends AbstractListDelimiterHandler

A specialized implementation of ListDelimiterHandler which simulates the list delimiter handling as it was used by PropertiesConfiguration in Commons Configuration 1.x.

This class mainly exists for compatibility reasons. It is intended to be used by applications which have to deal with properties files created by an older version of this library.

In the 1.x series of Commons Configuration list handling was not fully consistent. The escaping of property values was done in a different way if they contained a list delimiter or not. From version 2.0 on, escaping is more stringent which might cause slightly different results when parsing properties files created by or for Configuration 1.x. If you encounter such problems, you can switch to this ListDelimiterHandler implementation rather than the default one. In other cases, this class should not be used!

Implementation note: An instance of this class can safely be shared between multiple Configuration instances.

Since:
2.0

  • Constructor Details

    • LegacyListDelimiterHandler

      public LegacyListDelimiterHandler(char listDelimiter)
      Creates a new instance of LegacyListDelimiterHandler and sets the list delimiter character.
      Parameters:
      listDelimiter - the list delimiter character

  • Method Details

    • getDelimiter

      public char getDelimiter()
      Gets the list delimiter character.
      Returns:
      the list delimiter character

    • escape

      public Object escape(Object value, ValueTransformer transformer)
      Escapes the specified single value object. This method is called for properties containing only a single value. So this method can rely on the fact that the passed in object is not a list. An implementation has to check whether the value contains list delimiter characters and - if so - escape them accordingly. This implementation checks whether the object to be escaped is a string. If yes, it delegates to AbstractListDelimiterHandler.escapeString(String), otherwise no escaping is performed. Eventually, the passed in transformer is invoked so that additional encoding can be performed. This implementation performs delimiter escaping for a single value (which is not part of a list).
      Specified by:
      escape in interface ListDelimiterHandler
      Overrides:
      escape in class AbstractListDelimiterHandler
      Parameters:
      value - the value to be escaped
      transformer - a ValueTransformer for an additional encoding (must not be null)
      Returns:
      the escaped value

    • escapeList

      public Object escapeList(List<?> values, ValueTransformer transformer)
      Escapes all values in the given list and concatenates them to a single string. This operation is required by configurations that have to represent properties with multiple values in a single line in their external configuration representation. This may require an advanced escaping in some cases. This implementation performs a special encoding of backslashes at the end of a string so that they are not interpreted as escape character for a following list delimiter.
      Parameters:
      values - the list with all the values to be converted to a single value
      transformer - a ValueTransformer for an additional encoding (must not be null)
      Returns:
      the resulting escaped value

    • splitString

      protected Collection<String> splitString(String s, boolean trim)
      Actually splits the passed in string which is guaranteed to be not null. This method is called by the base implementation of the split() method. Here the actual splitting logic has to be implemented. This implementation simulates the old splitting algorithm. The string is split at the delimiter character if it is not escaped. If the delimiter character is not found, the input is returned unchanged.
      Specified by:
      splitString in class AbstractListDelimiterHandler
      Parameters:
      s - the string to be split (not null)
      trim - a flag whether the single components have to be trimmed
      Returns:
      a collection with the extracted components of the passed in string

    • escapeString

      protected String escapeString(String s)
      Escapes the specified string. This method is called by escape() if the passed in object is a string. Concrete subclasses have to implement their specific escaping logic here, so that the list delimiters they support are properly escaped. This is just a dummy implementation. It is never called.
      Specified by:
      escapeString in class AbstractListDelimiterHandler
      Parameters:
      s - the string to be escaped (not null)
      Returns:
      the escaped string

    • escapeBackslashs

      protected String escapeBackslashs(Object value, boolean inList)
      Performs the escaping of backslashes in the specified properties value. Because a double backslash is used to escape the escape character of a list delimiter, double backslashes also have to be escaped if the property is part of a (single line) list. In addition, because the output is written into a properties file, each occurrence of a backslash again has to be doubled. This method is called by escapeValue().
      Parameters:
      value - the value to be escaped
      inList - a flag whether the value is part of a list
      Returns:
      the value with escaped backslashes as string

    • escapeValue

      protected String escapeValue(Object value, boolean inList, ValueTransformer transformer)
      Escapes the given property value. This method is called on saving the configuration for each property value. It ensures a correct handling of backslash characters and also takes care that list delimiter characters in the value are escaped.
      Parameters:
      value - the property value
      inList - a flag whether the value is part of a list
      transformer - the ValueTransformer
      Returns:
      the escaped property value