Class CharEscaper
- Direct Known Subclasses:
ArrayBasedCharEscaper
,CharEscaperBuilder.CharArrayDecorator
For example, an XML escaper would convert the literal string "Foo<Bar>"
into
"Foo<Bar>"
to prevent "<Bar>"
from being confused with an XML tag. When the
resulting XML document is parsed, the parser API will return this text as the original literal
string "Foo<Bar>"
.
A CharEscaper
instance is required to be stateless, and safe when used concurrently by
multiple threads.
Popular escapers are defined as constants in classes like HtmlEscapers
and XmlEscapers
. To create
your own escapers extend this class and implement the escape(char)
method.
- Since:
- 15.0
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final int
The multiplier for padding to use when growing the escape buffer. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected abstract char[]
escape
(char c) Returns the escaped form of the given character, ornull
if this character does not need to be escaped.Returns the escaped form of a given literal string.protected final String
escapeSlow
(String s, int index) Returns the escaped form of a given literal string, starting at the given index.private static char[]
growBuffer
(char[] dest, int index, int size) Helper method to grow the character buffer as needed, this only happens once in a while so it's ok if it's in a method call.Methods inherited from class com.google.common.escape.Escaper
asFunction
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Field Details
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DEST_PAD_MULTIPLIER
private static final int DEST_PAD_MULTIPLIERThe multiplier for padding to use when growing the escape buffer.- See Also:
-
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Constructor Details
-
CharEscaper
protected CharEscaper()Constructor for use by subclasses.
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Method Details
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escape
Returns the escaped form of a given literal string.- Specified by:
escape
in classEscaper
- Parameters:
string
- the literal string to be escaped- Returns:
- the escaped form of
string
- Throws:
NullPointerException
- ifstring
is null
-
escape
@CheckForNull protected abstract char[] escape(char c) Returns the escaped form of the given character, ornull
if this character does not need to be escaped. If an empty array is returned, this effectively strips the input character from the resulting text.If the character does not need to be escaped, this method should return
null
, rather than a one-character array containing the character itself. This enables the escaping algorithm to perform more efficiently.An escaper is expected to be able to deal with any
char
value, so this method should not throw any exceptions.- Parameters:
c
- the character to escape if necessary- Returns:
- the replacement characters, or
null
if no escaping was needed
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escapeSlow
Returns the escaped form of a given literal string, starting at the given index. This method is called by theescape(String)
method when it discovers that escaping is required. It is protected to allow subclasses to override the fastpath escaping function to inline their escaping test. SeeCharEscaperBuilder
for an example usage.- Parameters:
s
- the literal string to be escapedindex
- the index to start escaping from- Returns:
- the escaped form of
string
- Throws:
NullPointerException
- ifstring
is null
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growBuffer
private static char[] growBuffer(char[] dest, int index, int size) Helper method to grow the character buffer as needed, this only happens once in a while so it's ok if it's in a method call. If the index passed in is 0 then no copying will be done.
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