@Beta @GwtCompatible public final class PercentEscaper extends UnicodeEscaper
UnicodeEscaper
that escapes some set of Java characters using a UTF-8 based percent encoding scheme. The set of safe characters (those which remain unescaped) can be specified on construction.
This class is primarily used for creating URI escapers in UrlEscapers
but can be used directly if required. While URI escapers impose specific semantics on which characters are considered 'safe', this class has a minimal set of restrictions.
When escaping a String, the following rules apply:
plusForSpace
was specified, the space character " " is converted into a plus sign "+"
. For performance reasons the only currently supported character encoding of this class is UTF-8.
Note: This escaper produces uppercase hexadecimal sequences. From RFC 3986:
"URI producers and normalizers should use uppercase hexadecimal digits for all percent-encodings."
Constructor and Description |
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PercentEscaper(String
Constructs a percent escaper with the specified safe characters and optional handling of the space character.
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Modifier and Type | Method and Description |
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protected char[] |
escape(int cp)
Escapes the given Unicode code point in UTF-8.
|
String |
escape(String
Returns the escaped form of a given literal string.
|
protected int |
nextEscapeIndex(CharSequence
Scans a sub-sequence of characters from a given
CharSequence , returning the index of the next character that requires escaping.
|
codePointAt, escapeSlow
asFunction
public PercentEscaper(StringsafeChars, boolean plusForSpace)
Not that it is allowed, but not necessarily desirable to specify %
as a safe character. This has the effect of creating an escaper which has no well defined inverse but it can be useful when escaping additional characters.
safeChars
- a non null string specifying additional safe characters for this escaper (the ranges 0..9, a..z and A..Z are always safe and should not be specified here)
plusForSpace
- true if ASCII space should be escaped to
+
rather than
%20
IllegalArgumentException
- if any of the parameters were invalid
protected int nextEscapeIndex(CharSequencecsq, int index, int end)
UnicodeEscaper
CharSequence
, returning the index of the next character that requires escaping.
Note: When implementing an escaper, it is a good idea to override this method for efficiency. The base class implementation determines successive Unicode code points and invokes UnicodeEscaper
for each of them. If the semantics of your escaper are such that code points in the supplementary range are either all escaped or all unescaped, this method can be implemented more efficiently using CharSequence
.
Note however that if your escaper does not escape characters in the supplementary range, you should either continue to validate the correctness of any surrogate characters encountered or provide a clear warning to users that your escaper does not validate its input.
See PercentEscaper
for an example.
nextEscapeIndex
in class
UnicodeEscaper
csq
- a sequence of characters
index
- the index of the first character to be scanned
end
- the index immediately after the last character to be scanned
public Stringescape(String s)
UnicodeEscaper
If you are escaping input in arbitrary successive chunks, then it is not generally safe to use this method. If an input string ends with an unmatched high surrogate character, then this method will throw IllegalArgumentException
. You should ensure your input is valid UTF-16 before calling this method.
Note: When implementing an escaper it is a good idea to override this method for efficiency by inlining the implementation of UnicodeEscaper
directly. Doing this for PercentEscaper
more than doubled the performance for unescaped strings (as measured by CharEscapersBenchmark
).
escape
in class
UnicodeEscaper
s
- the literal string to be escaped
string
protected char[] escape(int cp)
escape
in class
UnicodeEscaper
cp
- the Unicode code point to escape if necessary
null
if no escaping was needed