com.jaxfront.core.util
Class LanguageEnhancedProperties

java.lang.Object
  extended by java.util.Dictionary<K,V>
      extended by java.util.Hashtable<java.lang.Object,java.lang.Object>
          extended by java.util.Properties
              extended by com.jaxfront.core.util.LanguageEnhancedProperties
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, java.util.Map<java.lang.Object,java.lang.Object>
Direct Known Subclasses:
NLS

public class LanguageEnhancedProperties
extends java.util.Properties

The 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.

When saving properties to a stream or loading them from a stream, the ISO 8859-1 character encoding is used. For characters that cannot be directly represented in this encoding, Unicode escapes are used; however, 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.

Since:
JDK1.0
Version:
1.64, 06/26/00
Author:
Arthur van Hoff, Michael McCloskey
See Also:
native2ascii tool for Solaris, native2ascii tool for Windows, Serialized Form

Constructor Summary
LanguageEnhancedProperties()
          Creates an empty property list with no default values.
LanguageEnhancedProperties(LanguageEnhancedProperties defaults)
          Creates an empty property list with the specified defaults.
 
Method Summary
 void load(java.io.InputStream inStream)
          Reads a property list (key and element pairs) from the input stream.
 void load(java.io.Reader input)
           
 void save(java.io.OutputStream out, java.lang.String header)
          Deprecated. This method does not throw an IOException if an I/O error occurs while saving the property list. As of the Java 2 platform v1.2, the preferred way to save a properties list is via the store(OutputStream out, String header) method.
 void store(java.io.OutputStream out, java.lang.String header)
          Calls the store(OutputStream out, String header) method with the JAXFront.getDefaultFileEncoding!
 void store(java.io.Writer out, java.lang.String header)
          Calls the store(Writer out, String header) method without any encodings!
 
Methods inherited from class java.util.Properties
getProperty, getProperty, list, list, loadFromXML, propertyNames, setProperty, storeToXML, storeToXML
 
Methods inherited from class java.util.Hashtable
clear, clone, contains, containsKey, containsValue, elements, entrySet, equals, get, hashCode, isEmpty, keys, keySet, put, putAll, remove, size, toString, values
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

LanguageEnhancedProperties

public LanguageEnhancedProperties()
Creates an empty property list with no default values.


LanguageEnhancedProperties

public LanguageEnhancedProperties(LanguageEnhancedProperties defaults)
Creates an empty property list with the specified defaults.

Parameters:
defaults - the defaults.
Method Detail

load

public void load(java.io.InputStream inStream)
          throws java.io.IOException
Reads a property list (key and element pairs) from the input stream. The stream is assumed to be using the ISO 8859-1 character encoding; that is each byte is one Latin1 character. Characters not in Latin1, and certain special characters, can be represented in keys and elements using escape sequences similar to those used for character and string literals (see §3.3 and §3.10.6 of the Java Language Specification). The differences from the character escape sequences used for characters and strings are: An 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 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                  :Beauty
 
As 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:

cheeses
 
specifies that the key is "cheeses" and the associated element is the empty string "".

Overrides:
load in class java.util.Properties
Parameters:
inStream - the input stream.
Throws:
java.io.IOException - if an error occurred when reading from the input stream.
java.lang.IllegalArgumentException - if the input stream contains a malformed Unicode escape sequence.

load

public void load(java.io.Reader input)
          throws java.io.IOException
Throws:
java.io.IOException

save

public void save(java.io.OutputStream out,
                 java.lang.String header)
Deprecated. This method does not throw an IOException if an I/O error occurs while saving the property list. As of the Java 2 platform v1.2, the preferred way to save a properties list is via the store(OutputStream out, String header) method.

Calls the store(OutputStream out, String header) method and suppresses IOExceptions that were thrown. Uses the JAXFront.getDefaultFileEncoding!

Overrides:
save in class java.util.Properties
Parameters:
out - an output stream.
header - a description of the property list.
Throws:
java.lang.ClassCastException - if this Properties object contains any keys or values that are not Strings.

store

public void store(java.io.OutputStream out,
                  java.lang.String header)
           throws java.io.IOException
Calls the store(OutputStream out, String header) method with the JAXFront.getDefaultFileEncoding!

Overrides:
store in class java.util.Properties
Parameters:
out - an output stream.
header - a description of the property list.
Throws:
java.lang.ClassCastException - if this Properties object contains any keys or values that are not Strings.
java.io.IOException

store

public void store(java.io.Writer out,
                  java.lang.String header)
           throws java.io.IOException
Calls the store(Writer out, String header) method without any encodings!

Parameters:
out - an output stream.
header - a description of the property list.
Throws:
java.lang.ClassCastException - if this Properties object contains any keys or values that are not Strings.
java.io.IOException