public class NonBlockingProperties extends CommonsLinkedHashMap<String,String>
NonBlockingProperties class represents a persistent set of
properties. The NonBlockingProperties 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 NonBlockingProperties inherits from
CommonsTreeMap , the put and putAll
methods can be applied to a NonBlockingProperties 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" NonBlockingProperties object
that contains a non- String key or value, the call will fail.
Similarly, the call to the propertyNames or list
method will fail if it is called on a "compromised"
NonBlockingProperties object that contains a non-
String key.
The load(Reader) /
store(Writer, String)
methods load and store properties from and to a character based stream in a
simple line-oriented format specified below. The
load(InputStream) /
store(OutputStream,
String) methods work the same way as the load(Reader)/store(Writer, String)
pair, except the input/output stream is encoded in 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.
AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>| Modifier and Type | Field and Description |
|---|---|
protected NonBlockingProperties |
m_aDefaults
A property list that contains default values for any keys not found in this
property list.
|
| Constructor and Description |
|---|
NonBlockingProperties()
Creates an empty property list with no default values.
|
NonBlockingProperties(NonBlockingProperties aDefaults)
Creates an empty property list with the specified defaults.
|
| Modifier and Type | Method and Description |
|---|---|
static NonBlockingProperties |
create(Map<Object,Object> aProperties)
Create
NonBlockingProperties from an existing Properties
object. |
NonBlockingProperties |
getDefaults() |
String |
getProperty(String sKey)
Searches for the property with the specified key in this property list.
|
String |
getProperty(String sKey,
String sDefaultValue)
Searches for the property with the specified key in this property list.
|
void |
load(InputStream aIS)
Reads a property list (key and element pairs) from the input byte stream.
|
void |
load(Reader aReader)
Reads a property list (key and element pairs) from the input character
stream in a simple line-oriented format.
|
String |
setProperty(String sKey,
String sValue)
Calls the Hashtable method
put. |
void |
store(OutputStream aOS,
String sComments)
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(InputStream) method. |
void |
store(Writer aWriter,
String sComments)
Writes this property list (key and element pairs) in this
Properties table to the output character stream in a format
suitable for using the load(Reader) method. |
createInstance, getCloneclear, containsValue, entrySet, forEach, get, getOrDefault, keySet, removeEldestEntry, replaceAll, valuesclone, compute, computeIfAbsent, computeIfPresent, containsKey, isEmpty, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, sizeequals, hashCode, toStringfinalize, getClass, notify, notifyAll, wait, wait, waitcopyOfEntrySet, copyOfKeySet, copyOfKeySet, getLastKey, getLastKey, getLastValue, getLastValueaddAll, containsAnyEntry, containsAnyKey, containsAnyValue, copyOfValues, copyOfValues, copyOfValuesMapped, copyOfValuesMapped, findFirstEntry, findFirstKey, findFirstValue, forEach, forEachKey, forEachKey, forEachValue, forEachValue, getAsUnmodifiable, getFirstEntry, getFirstEntry, getFirstKey, getFirstKey, getFirstValue, getFirstValue, getSortedByKey, getSortedByValue, getSwappedKeyValues, isNotEmpty, put, putAll, putAll, putAllMapped, putAllMapped, putAllMapped, putIf, putIfNotNull, removeAll, removeIf, removeIfKey, removeIfValue, removeObject, setAllclear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, valuesprotected NonBlockingProperties m_aDefaults
public NonBlockingProperties()
public NonBlockingProperties(@Nullable NonBlockingProperties aDefaults)
aDefaults - the defaults.@Nullable public NonBlockingProperties getDefaults()
null.@Nullable public String setProperty(String sKey, String sValue)
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.sKey - the key to be placed into this property list.sValue - the value corresponding to key.null if it did not have one.getProperty(java.lang.String)public void load(@WillNotClose Reader aReader) throws IOException
Properties are processed in terms of lines. There are two kinds of line,
natural lines and logical lines. A natural line is defined as
a line of characters that is terminated either by a set of line terminator
characters (\n or \r or \r\n) or by
the end of the stream. A natural line may be either a blank line, a comment
line, or hold all or some of a key-element pair. A logical line holds all
the data of a key-element pair, which 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. Lines are read from input until
the end of the stream 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 format 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 of the following line have no affect on the key or element values. The remainder of the discussion of key and element parsing (when loading) 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 decide 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 "".
Characters in keys and elements can be represented in 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 and Unicode escapes used for characters and strings are:
\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'.
The specified stream remains open after this method returns.
aReader - the input character stream.IOException - if an error occurred when reading from the input stream.IllegalArgumentException - if a malformed Unicode escape appears in the input.public void load(@WillNotClose InputStream aIS) throws IOException
load(Reader) and is assumed to use the ISO
8859-1 character encoding; that is each byte is one Latin1 character.
Characters not in Latin1, and certain special characters, are represented
in keys and elements using
Unicode escapes.
The specified stream remains open after this method returns.
aIS - 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(@Nonnull @WillNotClose Writer aWriter, @Nullable String sComments) throws IOException
Properties table to the output character stream in a format
suitable for using the load(Reader) method.
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. Any one of a line feed ('\n'), a carriage return
('\r'), or a carriage return followed immediately by a line feed in
comments is replaced by a line separator generated by the
Writer and if the next character in comments is not character
# or character ! then an ASCII # is
written out after that line separator.
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. 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.
aWriter - an output character stream writer.sComments - 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 writer is null.public void store(@Nonnull @WillNotClose OutputStream aOS, @Nullable String sComments) throws IOException
Properties table to the output stream in a format suitable for
loading into a Properties table using the
load(InputStream) method.
Properties from the defaults table of this Properties table
(if any) are not written out by this method.
This method outputs the comments, properties keys and values in the same
format as specified in store(Writer), with the following differences:
\uxxxx for their appropriate unicode hexadecimal
value xxxx.
\u0020 and characters greater
than \u007E in property keys or values are written as
\uxxxx for the appropriate hexadecimal value
xxxx.
After the entries have been written, the output stream is flushed. The output stream remains open after this method returns.
aOS - an output stream.sComments - 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.@Nullable public String getProperty(@Nullable String sKey)
null if the property is not found.sKey - the property key.setProperty(java.lang.String, java.lang.String)@Nullable public String getProperty(@Nullable String sKey, @Nullable String sDefaultValue)
sKey - the map key.sDefaultValue - a default value.setProperty(java.lang.String, java.lang.String)@Nonnull public static NonBlockingProperties create(@Nullable Map<Object,Object> aProperties)
NonBlockingProperties from an existing Properties
object.aProperties - Source properties. May be null.NonBlockingProperties. Never
null.Copyright © 2014–2017 Philip Helger. All rights reserved.