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java.util

Class Properties

java.lang.Object
|
+--java.util.Dictionary
   |
   +--java.util.Hashtable
      |
      +--java.util.Properties


public class Properties

extends Hashtable

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:See Also:

Field Summary

java.util.Propertiesdefaults

The property list that contains default values for any keys not in this property list.

Constructor Summary

Properties()

Creates a new empty property list with no default values.
Properties(java.util.Properties defaults)

Create a new empty property list with the specified default values.

Method Summary

java.lang.StringgetProperty(java.lang.String key)

Gets the property with the specified key in this property list.
java.lang.StringgetProperty(java.lang.String key, java.lang.String defaultValue)

Gets the property with the specified key in this property list.
voidlist(java.io.PrintStream out)

Writes the key/value pairs to the given print stream.
voidlist(java.io.PrintWriter out)

Writes the key/value pairs to the given print writer.
voidload(java.io.InputStream inStream)

Reads a property list from an input stream.
java.util.EnumerationpropertyNames()

Returns an enumeration of all keys in this property list, including the keys in the default property list.
voidsave(java.io.OutputStream out, java.lang.String header)

Calls store(OutputStream out, String header) and ignores the IOException that may be thrown.
java.lang.ObjectsetProperty(java.lang.String key, java.lang.String value)

Adds the given key/value pair to this properties.
voidstore(java.io.OutputStream out, java.lang.String header)

Writes the key/value pairs to the given output stream, in a format suitable for load.

Field Details

defaults

protected Properties defaults

The property list that contains default values for any keys not in this property list.


Constructor Details

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:


Method Details

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:

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:

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 \\uxxxx 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:


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:

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 \uxxxx Form.
Following the listing, the output stream is flushed but left open.

Since:Parameters:

Throws: