PropertiesFile Class

class javaproperties.PropertiesFile(mapping=None, **kwargs)

New in version 0.3.0.

A custom mapping class for reading from, editing, and writing to a .properties file while preserving comments & whitespace in the original input.

A PropertiesFile instance can be constructed from another mapping and/or iterable of pairs, after which it will act like an OrderedDict. Alternatively, an instance can be constructed from a file or string with PropertiesFile.load() or PropertiesFile.loads(), and the resulting instance will remember the formatting of its input and retain that formatting when written back to a file or string with the dump() or dumps() method. The formatting information attached to an instance pf can be forgotten by constructing another mapping from it via dict(pf), OrderedDict(pf), or even PropertiesFile(pf) (Use the copy() method if you want to create another PropertiesFile instance with the same data & formatting).

When not reading or writing, PropertiesFile behaves like a normal MutableMapping class (i.e., you can do props[key] = value and so forth), except that (a) like OrderedDict, key insertion order is remembered and is used when iterating & dumping (and reversed is supported), and (b) like Properties, it may only be used to store strings and will raise a TypeError if passed a non-string object as key or value.

Two PropertiesFile instances compare equal iff both their key-value pairs and comment & whitespace lines are equal and in the same order. When comparing a PropertiesFile to any other type of mapping, only the key-value pairs are considered, and order is ignored.

PropertiesFile currently only supports reading & writing the simple line-oriented format, not XML.

copy()

Create a copy of the mapping, including formatting information

dump(fp, separator='=')

Write the mapping to a file in simple line-oriented .properties format.

If the instance was originally created from a file or string with PropertiesFile.load() or PropertiesFile.loads(), then the output will include the comments and whitespace from the original input, and any keys that haven’t been deleted or reassigned will retain their original formatting and multiplicity. Key-value pairs that have been modified or added to the mapping will be reformatted with join_key_value() using the given separator. All key-value pairs are output in the order they were defined, with new keys added to the end.

Note

Serializing a PropertiesFile instance with the dump() function instead will cause all formatting information to be ignored, as dump() will treat the instance like a normal mapping.

Parameters:

• fp – A file-like object to write the mapping to. It must have been opened as a text file with a Latin-1-compatible encoding.
• separator (text string) – The string to use for separating new or modified keys & values. Only " ", "=", and ":" (possibly with added whitespace) should ever be used as the separator.

Returns:

None

dumps(separator='=')

Convert the mapping to a text string in simple line-oriented .properties format.

If the instance was originally created from a file or string with PropertiesFile.load() or PropertiesFile.loads(), then the output will include the comments and whitespace from the original input, and any keys that haven’t been deleted or reassigned will retain their original formatting and multiplicity. Key-value pairs that have been modified or added to the mapping will be reformatted with join_key_value() using the given separator. All key-value pairs are output in the order they were defined, with new keys added to the end.

Note

Serializing a PropertiesFile instance with the dumps() function instead will cause all formatting information to be ignored, as dumps() will treat the instance like a normal mapping.

Parameters:separator (text string) – The string to use for separating new or modified keys & values. Only " ", "=", and ":" (possibly with added whitespace) should ever be used as the separator. Return type:text string

classmethod load(fp)

Parse the contents of the readline-supporting file-like object fp as a simple line-oriented .properties file and return a PropertiesFile instance.

fp may be either a text or binary filehandle, with or without universal newlines enabled. If it is a binary filehandle, its contents are decoded as Latin-1.

Parameters:fp (file-like object) – the file from which to read the .properties document Return type:PropertiesFile

classmethod loads(s)

Parse the contents of the string s as a simple line-oriented .properties file and return a PropertiesFile instance.

s may be either a text string or bytes string. If it is a bytes string, its contents are decoded as Latin-1.

Parameters:s (string) – the string from which to read the .properties document Return type:PropertiesFile