public class PropertiesRaw extends Hashtable<Object,Object>
Properties class represents a persistent set of properties.
The Properties can be saved to a stream or loaded from a stream.
Each key and its corresponding value in the property list is a string.
A property list can contain another property list as its "defaults"; this second property list is searched if the property key is not found in the original property list.
Because Properties inherits from Hashtable, the
put and putAll methods can be applied to a
Properties object. Their use is strongly discouraged as they
allow the caller to insert entries whose keys or values are not
Strings. The setProperty method should be used
instead. If the store or save method is called on a
"compromised" Properties object that contains a non-
String key or value, the call will fail.
The load and store methods load and store
properties in a simple line-oriented format specified below. This format uses
the ISO 8859-1 character encoding. Characters that cannot be directly
represented in this encoding can be written using Unicode
escapes ; only a single 'u' character is allowed in an escape sequence.
The native2ascii tool can be used to convert property files to and from other
character encodings.
The #loadFromXML(InputStream) and
#storeToXML(OutputStream, String, String) methods load and store
properties in a simple XML format. By default the UTF-8 character encoding is
used, however a specific encoding may be specified if required. An XML
properties document has the following DOCTYPE declaration:
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">Note that the system URI (http://java.sun.com/dtd/properties.dtd) is not accessed when exporting or importing properties; it merely serves as a string to uniquely identify the DTD, which is:
<?xml version="1.0" encoding="UTF-8"?>
<!-- DTD for properties -->
<!ELEMENT properties ( comment?, entry* ) >
<!ATTLIST properties version CDATA #FIXED "1.0">
<!ELEMENT comment (#PCDATA) >
<!ELEMENT entry (#PCDATA) >
<!ATTLIST entry key CDATA #REQUIRED>
| Modifier and Type | Field and Description |
|---|---|
protected PropertiesRaw |
defaults
A property list that contains default values for any keys not found in
this property list.
|
| Constructor and Description |
|---|
PropertiesRaw()
Creates an empty property list with no default values.
|
PropertiesRaw(PropertiesRaw defaults)
Creates an empty property list with the specified defaults.
|
| Modifier and Type | Method and Description |
|---|---|
String |
getProperty(String key)
Searches for the property with the specified key in this property list.
|
String |
getProperty(String key,
String defaultValue)
Searches for the property with the specified key in this property list.
|
void |
list(PrintStream out)
Prints this property list out to the specified output stream.
|
void |
list(PrintWriter out)
Prints this property list out to the specified output stream.
|
void |
load(InputStream inStream) |
void |
load(InputStream inStream,
Charset charset) |
void |
load(Reader inStream)
Reads a property list (key and element pairs) from the input stream.
|
Enumeration<?> |
propertyNames()
Returns an enumeration of all the keys in this property list, including
distinct keys in the default property list if a key of the same name has
not already been found from the main properties list.
|
Object |
setProperty(String key,
String value)
Calls the Hashtable method
put. |
void |
store(OutputStream outStream) |
void |
store(OutputStream outStream,
Charset charset) |
void |
store(Writer out)
Writes this property list (key and element pairs) in this
Properties table to the output stream in a format suitable
for loading into a Properties table using the
load method. |
protected PropertiesRaw defaults
public PropertiesRaw()
public PropertiesRaw(PropertiesRaw defaults)
defaults - the defaults.public Object setProperty(String key, String value)
put. Provided for
parallelism with the getProperty method. Enforces use of strings
for property keys and values. The value returned is the result of the
Hashtable call to put.key - the key to be placed into this property list.value - the value corresponding to key.null if it did not have one.getProperty(java.lang.String)public void load(InputStream inStream) throws IOException
IOExceptionpublic void load(InputStream inStream, Charset charset) throws IOException
IOExceptionpublic void load(Reader inStream) throws IOException
\b does not represent a
backspace character.
\,
before a non-valid escape character as an error; the backslash is
silently dropped. For example, in a Java string the sequence "\z"
would cause a compile time error. In contrast, this method
silently drops the backslash. Therefore, this method treats the two
character sequence "\b" as equivalent to the single
character 'b'.
IllegalArgumentException is thrown if a malformed Unicode
escape appears in the input.
This method processes input in terms of lines. A natural line of input is
terminated either by a set of line terminator characters (\n
or \r or \r\n) or by the end of the file. A
natural line may be either a blank line, a comment line, or hold some
part of a key-element pair. The logical line holding all the data for a
key-element pair may be spread out across several adjacent natural lines
by escaping the line terminator sequence with a backslash character,
\. Note that a comment line cannot be extended in this
manner; every natural line that is a comment must have its own comment
indicator, as described below. If a logical line is continued over
several natural lines, the continuation lines receive further processing,
also described below. Lines are read from the input stream until end of
file is reached.
A natural line that contains only white space characters is considered
blank and is ignored. A comment line has an ASCII '#' or
'!' as its first non-white space character; comment lines
are also ignored and do not encode key-element information. In addition
to line terminators, this method considers the characters space (
' ', '\u0020'), tab ('\t', '\u0009'), and form feed
('\f', '\u000C') to be white space.
If a logical line is spread across several natural lines, the backslash escaping the line terminator sequence, the line terminator sequence, and any white space at the start the following line have no affect on the key or element values. The remainder of the discussion of key and element parsing will assume all the characters constituting the key and element appear on a single natural line after line continuation characters have been removed. Note that it is not sufficient to only examine the character preceding a line terminator sequence to see if the line terminator is escaped; there must be an odd number of contiguous backslashes for the line terminator to be escaped. Since the input is processed from left to right, a non-zero even number of 2n contiguous backslashes before a line terminator (or elsewhere) encodes n backslashes after escape processing.
The key contains all of the characters in the line starting with the
first non-white space character and up to, but not including, the first
unescaped '=', ':', or white space character
other than a line terminator. All of these key termination characters may
be included in the key by escaping them with a preceding backslash
character; for example,
\:\=
would be the two-character key ":=". Line terminator
characters can be included using \r and \n
escape sequences. Any white space after the key is skipped; if the first
non-white space character after the key is '=' or
':', then it is ignored and any white space characters after
it are also skipped. All remaining characters on the line become part of
the associated element string; if there are no remaining characters, the
element is the empty string "". Once the raw
character sequences constituting the key and element are identified,
escape processing is performed as described above.
As an example, each of the following three lines specifies the key
"Truth" and the associated element value
"Beauty":
Truth = Beauty Truth:Beauty Truth :BeautyAs another example, the following three lines specify a single property:
fruits apple, banana, pear, \
cantaloupe, watermelon, \
kiwi, mango
The key is "fruits" and the associated element is:
"apple, banana, pear, cantaloupe, watermelon, kiwi, mango"Note that a space appears before each
\ so that a space will
appear after each comma in the final result; the \, line
terminator, and leading white space on the continuation line are merely
discarded and are not replaced by one or more other characters.
As a third example, the line:
cheesesspecifies that the key is
"cheeses" and the associated
element is the empty string "".
inStream - the input stream.IOException - if an error occurred when reading from the input stream.IllegalArgumentException - if the input stream contains a malformed Unicode escape
sequence.public void store(OutputStream outStream) throws IOException
IOExceptionpublic void store(OutputStream outStream, Charset charset) throws IOException
IOExceptionpublic void store(Writer out) throws IOException
Properties table to the output stream in a format suitable
for loading into a Properties table using the
load method. The stream is written using the
ISO 8859-1 character encoding.
Properties from the defaults table of this Properties table
(if any) are not written out by this method.
If the comments argument is not null, then an ASCII #
character, the comments string, and a line separator are first written to
the output stream. Thus, the comments can serve as an
identifying comment.
Next, a comment line is always written, consisting of an ASCII
# character, the current date and time (as if produced by
the toString method of Date for the current
time), and a line separator as generated by the Writer.
Then every entry in this Properties table is written out,
one per line. For each entry the key string is written, then an ASCII
=, then the associated element string. Each character of the
key and element strings is examined to see whether it should be rendered
as an escape sequence. The ASCII characters \, tab, form
feed, newline, and carriage return are written as \\,
\t, \f \n, and \r,
respectively. Characters less than \u0020 and characters
greater than \u007E are written as \u
xxxx for the appropriate hexadecimal value xxxx. For the
key, all space characters are written with a preceding \
character. For the element, leading space characters, but not embedded or
trailing space characters, are written with a preceding \
character. The key and element characters #, !,
=, and : are written with a preceding backslash
to ensure that they are properly loaded.
After the entries have been written, the output stream is flushed. The output stream remains open after this method returns.
out - an output stream.comments - a description of the property list.IOException - if writing this property list to the specified output
stream throws an IOException.ClassCastException - if this Properties object contains any keys
or values that are not Strings.NullPointerException - if out is null.public String getProperty(String key)
null if the property is not found.key - the property key.setProperty(java.lang.String, java.lang.String),
defaultspublic String getProperty(String key, String defaultValue)
key - the hashtable key.defaultValue - a default value.setProperty(java.lang.String, java.lang.String),
defaultspublic Enumeration<?> propertyNames()
Enumeration,
Properties.defaultspublic void list(PrintStream out)
out - an output stream.public void list(PrintWriter out)
out - an output stream.Copyright © 2014. All rights reserved.