Top Description Fields Constructors Methods
com.google.common.escape

public abstract Class CharEscaper

extends Escaper
Class Inheritance
Known Direct Subclasses
com.google.common.escape.CharEscaperBuilder.CharArrayDecorator, com.google.common.escape.ArrayBasedCharEscaper
Annotations
@GwtCompatible
@ElementTypesAreNonnullByDefault
Static Imports
com.google.common.base.Preconditions.checkNotNull
An object that converts literal text into a format safe for inclusion in a particular context (such as an XML document). Typically (but not always), the inverse process of "unescaping" the text is performed automatically by the relevant parser.

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 com.google.common.html.HtmlEscapers and com.google.common.xml.XmlEscapers. To create your own escapers extend this class and implement the escape(char) method.

Author
Sven Mawson
Since
15.0

Field Summary

Modifier and TypeField and Description
private static final int
DEST_PAD_MULTIPLIER

The multiplier for padding to use when growing the escape buffer.

Constructor Summary

AccessConstructor and Description
protected
CharEscaper()

Constructor for use by subclasses.

Method Summary

Modifier and TypeMethod and Description
public String

Returns:

the escaped form of string
escape(String
the literal string to be escaped
string)

Implements abstract com.google.common.escape.Escaper.escape.

Returns the escaped form of a given literal string.
protected abstract char[]

Returns:

the replacement characters, or null if no escaping was needed
escape(char
the character to escape if necessary
c)

Returns the escaped form of the given character, or null if this character does not need to be escaped.

protected final String

Returns:

the escaped form of string
escapeSlow(String
the literal string to be escaped
s, int
the index to start escaping from
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.

Inherited from com.google.common.escape.Escaper:
asFunction

Field Detail

DEST_PAD_MULTIPLIERback to summary
private static final int DEST_PAD_MULTIPLIER

The multiplier for padding to use when growing the escape buffer.

Constructor Detail

CharEscaperback to summary
protected CharEscaper()

Constructor for use by subclasses.

Method Detail

escapeback to summary
public String escape(String string)

Implements abstract com.google.common.escape.Escaper.escape.

Returns the escaped form of a given literal string.

Parameters
string:String

the literal string to be escaped

Returns:String

the escaped form of string

Annotations
@Override
Exceptions
NullPointerException:
if string is null
escapeback to summary
protected abstract char[] escape(char c)

Returns the escaped form of the given character, or null 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:char

the character to escape if necessary

Returns:char[]

the replacement characters, or null if no escaping was needed

Annotations
@CheckForNull
escapeSlowback to summary
protected final String escapeSlow(String s, int index)

Returns the escaped form of a given literal string, starting at the given index. This method is called by the escape(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. See CharEscaperBuilder for an example usage.

Parameters
s:String

the literal string to be escaped

index:int

the index to start escaping from

Returns:String

the escaped form of string

Exceptions
NullPointerException:
if string is null
growBufferback to summary
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.