JsonReadFeature.java
package tools.jackson.core.json;
import tools.jackson.core.*;
/**
* Token reader (parser) features specific to JSON backend.
*<p>
* NOTE: Jackson 2.x had these mixed with non-JSON-specific features within
* <code>JsonParser.Feature</code> enumeration.
*/
public enum JsonReadFeature
implements FormatFeature
{
// // // Support for non-standard data format constructs: comments
/**
* Feature that determines whether parser will allow use
* of Java/C/C++ style comments (both '/'+'*' and
* '//' varieties) within parsed content or not.
*<p>
* Since JSON specification does not mention comments as legal
* construct,
* this is a non-standard feature; however, in the wild
* this is extensively used. As such, feature is
* <b>disabled by default</b> for parsers and must be
* explicitly enabled.
*/
ALLOW_JAVA_COMMENTS(false),
/**
* Feature that determines whether parser will allow use
* of YAML comments, ones starting with '#' and continuing
* until the end of the line. This commenting style is common
* with scripting languages as well.
*<p>
* Since JSON specification does not mention comments as legal
* construct,
* this is a non-standard feature. As such, feature is
* <b>disabled by default</b> for parsers and must be
* explicitly enabled.
*/
ALLOW_YAML_COMMENTS(false),
// // // Support for non-standard data format constructs: quoting/escaping
/**
* Feature that can be enabled to accept quoting of all character
* using backslash quoting mechanism: if not enabled, only characters
* that are explicitly listed by JSON specification can be thus
* escaped (see JSON spec for small list of these characters)
*<p>
* Since JSON specification requires quoting for all control characters,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_BACKSLASH_ESCAPING_ANY_CHARACTER(false),
/**
* Feature that determines whether parser will allow use
* of single quotes (apostrophe, character '\'') for
* quoting Strings (names and String values). If so,
* this is in addition to other acceptable markers.
*<p>
* Since JSON specification requires use of double quotes for
* property names,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_SINGLE_QUOTES(false),
/**
* Feature that determines whether parser will allow
* Record Separator (RS) control character ({@code 0x1E})
* as part of ignorable whitespace in JSON input, similar to the TAB character.
* <p>
* Since the official JSON specification permits only a limited set of control
* characters as whitespace, this is a non-standard feature and is disabled by default.
*/
ALLOW_RS_CONTROL_CHAR(false),
/**
* Feature that determines whether parser will allow
* JSON Strings to contain unescaped control characters
* (ASCII characters with value less than 32, including
* tab and line feed characters) or not.
* If feature is set false, an exception is thrown if such a
* character is encountered.
*<p>
* Since JSON specification requires quoting for all control characters,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_UNESCAPED_CONTROL_CHARS(false),
/**
* Feature that determines whether parser will allow use
* of unquoted Object property names (which is allowed by Javascript,
* but not by JSON specification).
*<p>
* Since JSON specification requires use of double quotes for
* Object property names,
* this is a non-standard feature, and as such disabled by default.
*<p>
* NOTE: in Jackson 2.x, was called {@code ALLOW_UNQUOTED_FIELD_NAMES}
*/
ALLOW_UNQUOTED_PROPERTY_NAMES(false),
// // // Support for non-standard data format constructs: number representations
/**
* Feature that determines whether parser will allow
* JSON decimal numbers to start with a decimal point
* (like: {@code .123}). If enabled, no exception is thrown, and the number
* is parsed as though a leading 0 had been present.
*<p>
* Since JSON specification does not allow leading decimal points,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_LEADING_DECIMAL_POINT_FOR_NUMBERS(false),
/**
* Feature that determines whether parser will allow
* JSON decimal numbers to start with a plus sign
* (like: {@code +123}). If enabled, no exception is thrown, and the number
* is parsed as though a leading sign had not been present.
*<p>
* Since JSON specification does not allow leading plus signs,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_LEADING_PLUS_SIGN_FOR_NUMBERS(false),
/**
* Feature that determines whether parser will allow
* JSON integral numbers to start with additional (ignorable)
* zeroes (like: {@code 000001}). If enabled, no exception is thrown, and extra
* nulls are silently ignored (and not included in textual representation
* exposed via {@link JsonParser#getString()}).
*<p>
* Since JSON specification does not allow leading zeroes,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_LEADING_ZEROS_FOR_NUMBERS(false),
/**
* Feature that allows parser to recognize set of
* "Not-a-Number" (NaN) tokens as legal floating number
* values (similar to how many other data formats and
* programming language source code allows it).
* Specific subset contains values that
* <a href="http://www.w3.org/TR/xmlschema-2/">XML Schema</a>
* (see section 3.2.4.1, Lexical Representation)
* allows (tokens are quoted contents, not including quotes):
*<ul>
* <li>"INF" (for positive infinity), as well as alias of "Infinity"
* <li>"-INF" (for negative infinity), alias "-Infinity"
* <li>"NaN" (for other not-a-numbers, like result of division by zero)
*</ul>
*<p>
* Since JSON specification does not allow use of such values,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_NON_NUMERIC_NUMBERS(false),
/**
* Feature that determines whether parser will allow
* JSON decimal numbers to end with a decimal point
* (like: {@code 123.}). If enabled, no exception is thrown, and the number
* is parsed as though the trailing decimal point had not been present.
*<p>
* Since JSON specification does not allow trailing decimal points,
* this is a non-standard feature, and as such disabled by default.
*/
ALLOW_TRAILING_DECIMAL_POINT_FOR_NUMBERS(false),
// // // Support for non-standard data format constructs: array/value separators
/**
* Feature allows the support for "missing" values in a JSON array: missing
* value meaning sequence of two commas, without value in-between but only
* optional white space.
* Enabling this feature will expose "missing" values as {@link JsonToken#VALUE_NULL}
* tokens, which typically become Java nulls in arrays and {@link java.util.Collection}
* in data-binding.
* <p>
* For example, enabling this feature will represent a JSON array <code>["value1",,"value3",]</code>
* as <code>["value1", null, "value3", null]</code>
* <p>
* Since the JSON specification does not allow missing values this is a non-compliant JSON
* feature and is disabled by default.
*/
ALLOW_MISSING_VALUES(false),
/**
* Feature that determines whether {@link JsonParser} will allow for a single trailing
* comma following the final value (in an Array) or member (in an Object). These commas
* will simply be ignored.
* <p>
* For example, when this feature is enabled, <code>[true,true,]</code> is equivalent to
* <code>[true, true]</code> and <code>{"a": true,}</code> is equivalent to
* <code>{"a": true}</code>.
* <p>
* When combined with <code>ALLOW_MISSING_VALUES</code>, this feature takes priority, and
* the final trailing comma in an array declaration does not imply a missing
* (<code>null</code>) value. For example, when both <code>ALLOW_MISSING_VALUES</code>
* and <code>ALLOW_TRAILING_COMMA</code> are enabled, <code>[true,true,]</code> is
* equivalent to <code>[true, true]</code>, and <code>[true,true,,]</code> is equivalent to
* <code>[true, true, null]</code>.
* <p>
* Since the JSON specification does not permit trailing commas, this is a non-standard
* feature, and as such disabled by default.
*/
ALLOW_TRAILING_COMMA(false),
;
private final boolean _defaultState;
private final int _mask;
/**
* Method that calculates bit set (flags) of all features that
* are enabled by default.
*
* @return Bit mask of all features that are enabled by default
*/
public static int collectDefaults()
{
int flags = 0;
for (JsonReadFeature f : values()) {
if (f.enabledByDefault()) {
flags |= f.getMask();
}
}
return flags;
}
private JsonReadFeature(boolean defaultState) {
_defaultState = defaultState;
_mask = (1 << ordinal());
}
@Override
public boolean enabledByDefault() { return _defaultState; }
@Override
public int getMask() { return _mask; }
@Override
public boolean enabledIn(int flags) { return (flags & _mask) != 0; }
}