java.util
Class Properties
java.lang.Object
|
+--java.util.Dictionary
|
+--java.util.Hashtable
|
+--java.util.Properties
A set of persistent properties, which can be saved or loaded from a stream.
A property list may also contain defaults, searched if the main list
does not contain a property for a given key.
An example of a properties file for the german language is given
here. This extends the example given in ListResourceBundle.
Create a file MyResource_de.properties with the following contents
and put it in the CLASSPATH. (The character
\
u00e4
is the german ä)
s1=3
s2=MeineDisk
s3=3. M\
u00e4rz 96
s4=Die Diskette ''{1}'' enth\
u00e4lt {0} in {2}.
s5=0
s6=keine Dateien
s7=1
s8=eine Datei
s9=2
s10={0,number} Dateien
s11=Das Formatieren schlug fehl mit folgender Exception: {0}
s12=FEHLER
s13=Ergebnis
s14=Dialog
s15=Auswahlkriterium
s16=1,3
Although this is a sub class of a hash table, you should never
insert anything other than strings to this property, or several
methods, that need string keys and values, will fail. To ensure
this, you should use the get/setProperty
method instead
of get/put
.
Properties are saved in ISO 8859-1 encoding, using Unicode escapes with
a single u
for any character which cannot be represented.
Authors:- Jochen Hoenicke
- Eric Blake <ebb9@email.byu.edu>
See Also:
defaults
protected Properties defaults
The property list that contains default values for any keys not
in this property list.
Properties
public Properties()
Creates a new empty property list with no default values.
Properties
public Properties(java.util.Properties defaults)
Create a new empty property list with the specified default values.
Parameters:
getProperty
public String getProperty(java.lang.String key)
Gets the property with the specified key in this property list.
If the key is not found, the default property list is searched.
If the property is not found in the default, null is returned.
Parameters:
Returns:
- the value for the given key, or null if not found
Throws:
See Also:
getProperty
public String getProperty(java.lang.String key, java.lang.String defaultValue)
Gets the property with the specified key in this property list. If
the key is not found, the default property list is searched. If the
property is not found in the default, the specified defaultValue is
returned.
Parameters:
Returns:
- The value for the given key
Throws:
See Also:
list
public void list(java.io.PrintStream out)
Writes the key/value pairs to the given print stream. They are
written in the way described in the method store. This does not visit
the keys in the default properties.
Parameters:
Throws:
See Also:
list
public void list(java.io.PrintWriter out)
Writes the key/value pairs to the given print writer. They are
written in the way, described in the method store.
Since:Parameters:
Throws:
See Also:
load
public void load(java.io.InputStream inStream)
Reads a property list from an input stream. The stream should
have the following format:
An empty line or a line starting with
#
or
!
is ignored. An backslash (
\
) at the
end of the line makes the line continueing on the next line
(but make sure there is no whitespace after the backslash).
Otherwise, each line describes a key/value pair.
The chars up to the first whitespace, = or : are the key. You
can include this caracters in the key, if you precede them with
a backslash (
\
). The key is followed by optional
whitespaces, optionally one
=
or
:
,
and optionally some more whitespaces. The rest of the line is
the resource belonging to the key.
Escape sequences
\t, \n, \r, \\, \", \', \!, \#, \
(a
space), and unicode characters with the
\\u
xxxx notation are detected, and
converted to the corresponding single character.
# This is a comment
key = value
k\:5 \ a string starting with space and ending with newline\n
# This is a multiline specification; note that the value contains
# no white space.
weekdays: Sunday,Monday,Tuesday,Wednesday,\\
Thursday,Friday,Saturday
# The safest way to include a space at the end of a value:
label = Name:\\u0020
Parameters:
Throws:
propertyNames
public Enumeration propertyNames()
Returns an enumeration of all keys in this property list, including
the keys in the default property list.
Returns:
- an Enumeration of all defined keys
save
public void save(java.io.OutputStream out, java.lang.String header)
Calls store(OutputStream out, String header)
and
ignores the IOException that may be thrown.
Parameters:
Throws:
setProperty
public Object setProperty(java.lang.String key, java.lang.String value)
Adds the given key/value pair to this properties. This calls
the hashtable method put.
Since:Parameters:
Returns:
- The old value for the given key
See Also:
store
public void store(java.io.OutputStream out, java.lang.String header)
Writes the key/value pairs to the given output stream, in a format
suitable for load
.
If header is not null, this method writes a comment containing
the header as first line to the stream. The next line (or first
line if header is null) contains a comment with the current date.
Afterwards the key/value pairs are written to the stream in the
following format.
Each line has the form key = value
. Newlines,
Returns and tabs are written as \n,\t,\r
resp.
The characters \, !, #, =
and :
are
preceeded by a backslash. Spaces are preceded with a backslash,
if and only if they are at the beginning of the key. Characters
that are not in the ascii range 33 to 127 are written in the
\
u
xxxx Form.
Following the listing, the output stream is flushed but left open.
Since:Parameters:
Throws:
\
u00e4
is the german ä)Although this is a sub class of a hash table, you should never insert anything other than strings to this property, or several methods, that need string keys and values, will fail. To ensure this, you should use the
get/setProperty
method instead ofget/put
. Properties are saved in ISO 8859-1 encoding, using Unicode escapes with a singleu
for any character which cannot be represented.