Package org.unbescape.css

Enum CssStringEscapeLevel

Object

Enum<CssStringEscapeLevel>

org.unbescape.css.CssStringEscapeLevel

All Implemented Interfaces:

java.io.Serializable, Comparable<CssStringEscapeLevel>

public enum CssStringEscapeLevel
extends Enum<CssStringEscapeLevel>

Levels defined for escape/unescape operations of CSS strings:

• Level 1: Escape only the basic escape set. Note the result of a level-1 escape operation might still contain non-ASCII characters if they existed in input, and therefore you will still need to correctly manage your input/output character encoding settings. Such basic set consists of:
  • The Backslash Escapes:
    • The quote symbols: \" (U+0022) and \' (U+0027).
    • The backslash: \\ (U+005C).
    • The slash (solidus) symbol (/, U+002F), which will be escaped in order to protect from code injection in HTML environments: browsers will parse </style> close tags inside CSS literals and close the tag, therefore allowing for further code injection.
    • The ampersand (&, U+0026) and semi-colon (;, U+003B) symbols, which will be escaped in order to protect from code injection in XHTML environments: browsers will parse XHTML escape codes inside literals in <style> tags, therefore allowing the closing of the literal and the <style> tag itself.
  • Two ranges of non-displayable, control characters: U+0000 to U+001F and U+007F to U+009F.
• Level 2: Escape the basic escape set (as defined in level 1), plus all non-ASCII characters. The result of a level-2 escape operation is therefore always ASCII-only text, and safer to use in complex scenarios with mixed input/output character encodings.
• Level 3: Escape all non-alphanumeric characters, this is, all but those in the A-Z, a-z and 0-9 ranges. This level can be safely used for completely escaping texts, including whitespace, line feeds, punctuation, etc. in scenarios where this adds an extra level of safety.
• Level 4: Escape all characters, even alphanumeric ones.

For further information, see the Glossary and the References sections at the documentation for the CssEscape class.

Since:

1.0.0

Author:

Daniel Fernández

Enum Constant Summary

Enum Constants

Enum Constant	Description
LEVEL_1_BASIC_ESCAPE_SET	Level 1 escape: escape only the basic escape set: Backslash Escape plus non-displayable control chars.
LEVEL_2_ALL_NON_ASCII_PLUS_BASIC_ESCAPE_SET	Level 2 escape: escape the basic escape set plus all non-ASCII characters (result will always be ASCII).
LEVEL_3_ALL_NON_ALPHANUMERIC	Level 3 escape: escape all non-alphanumeric characteres (escape all but those in the A-Z, a-z and 0-9 ranges).
LEVEL_4_ALL_CHARACTERS	Level 4 escape: escape all characters, including alphanumeric.

Method Summary

Modifier and Type	Method	Description
static CssStringEscapeLevel	forLevel(int level)	Utility method for obtaining an enum value from its corresponding int level value.
int	getEscapeLevel()	Return the int escape level.
static CssStringEscapeLevel	valueOf(String name)	Returns the enum constant of this type with the specified name.
static CssStringEscapeLevel[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

LEVEL_1_BASIC_ESCAPE_SET

public static final CssStringEscapeLevel LEVEL_1_BASIC_ESCAPE_SET

Level 1 escape: escape only the basic escape set: Backslash Escape plus non-displayable control chars.

LEVEL_2_ALL_NON_ASCII_PLUS_BASIC_ESCAPE_SET

public static final CssStringEscapeLevel LEVEL_2_ALL_NON_ASCII_PLUS_BASIC_ESCAPE_SET

Level 2 escape: escape the basic escape set plus all non-ASCII characters (result will always be ASCII).

LEVEL_3_ALL_NON_ALPHANUMERIC

public static final CssStringEscapeLevel LEVEL_3_ALL_NON_ALPHANUMERIC

Level 3 escape: escape all non-alphanumeric characteres (escape all but those in the A-Z, a-z and 0-9 ranges).

LEVEL_4_ALL_CHARACTERS

public static final CssStringEscapeLevel LEVEL_4_ALL_CHARACTERS

Level 4 escape: escape all characters, including alphanumeric.

Method Detail

values

public static CssStringEscapeLevel[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (CssStringEscapeLevel c : CssStringEscapeLevel.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static CssStringEscapeLevel valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

forLevel

public static CssStringEscapeLevel forLevel(int level)

Utility method for obtaining an enum value from its corresponding int level value.

Parameters:

level - the level

Returns:

the escape level enum constant, or IllegalArgumentException if level does not exist.

getEscapeLevel

public int getEscapeLevel()

Return the int escape level.

Returns:

the escape level.