JsonGenerator.Feature
Date: 2016-12-03

com.fasterxml.jackson.core

## Enum JsonGenerator.Feature

- java.lang.Object
- - java.lang.Enum<JsonGenerator.Feature>
  - - com.fasterxml.jackson.core.JsonGenerator.Feature

- All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<JsonGenerator.Feature>
  Enclosing class:
    JsonGenerator

      public static enum JsonGenerator.Feature
      extends java.lang.Enum<JsonGenerator.Feature>

  Enumeration that defines all togglable features for generators.

- - ### Enum Constant Summary

    Enum Constants
    Enum Constant and Description
    `AUTO_CLOSE_JSON_CONTENT` Feature that determines what happens when the generator is closed while there are still unmatched `JsonToken.START_ARRAY` or `JsonToken.START_OBJECT` entries in output content.
    `AUTO_CLOSE_TARGET` Feature that determines whether generator will automatically close underlying output target that is NOT owned by the generator.
    `ESCAPE_NON_ASCII` Feature that specifies that all characters beyond 7-bit ASCII range (i.e.
    `FLUSH_PASSED_TO_STREAM` Feature that specifies that calls to `JsonGenerator.flush()` will cause matching `flush()` to underlying `OutputStream` or `Writer`; if disabled this will not be done.
    `IGNORE_UNKNOWN` Feature that determines what to do if the underlying data format requires knowledge of all properties to output, and if no definition is found for a property that caller tries to write.
    `QUOTE_FIELD_NAMES` Feature that determines whether JSON Object field names are quoted using double-quotes, as specified by JSON specification or not.
    `QUOTE_NON_NUMERIC_NUMBERS` Feature that determines whether "exceptional" (not real number) float/double values are output as quoted strings.
    `STRICT_DUPLICATE_DETECTION` Feature that determines whether `JsonGenerator` will explicitly check that no duplicate JSON Object field names are written.
    `WRITE_BIGDECIMAL_AS_PLAIN` Feature that determines whether `BigDecimal` entries are serialized using `BigDecimal.toPlainString()` to prevent values to be written using scientific notation.
    `WRITE_NUMBERS_AS_STRINGS` Feature that forces all Java numbers to be written as JSON strings.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `static int` | `collectDefaults()` Method that calculates bit set (flags) of all features that are enabled by default.
    `boolean` | `enabledByDefault()`
    `boolean` | `enabledIn(int flags)`
    `int` | `getMask()`
    `static JsonGenerator.Feature` | `valueOf(java.lang.String name)` Returns the enum constant of this type with the specified name.
    `static JsonGenerator.Feature[]` | `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

    - #### AUTO_CLOSE_TARGET

          public static final JsonGenerator.Feature AUTO_CLOSE_TARGET

      Feature that determines whether generator will automatically close underlying output target that is NOT owned by the generator. If disabled, calling application has to separately close the underlying `OutputStream` and `Writer` instances used to create the generator. If enabled, generator will handle closing, as long as generator itself gets closed: this happens when end-of-input is encountered, or generator is closed by a call to `JsonGenerator.close()`.

      Feature is enabled by default.

    - #### AUTO_CLOSE_JSON_CONTENT

          public static final JsonGenerator.Feature AUTO_CLOSE_JSON_CONTENT

      Feature that determines what happens when the generator is closed while there are still unmatched `JsonToken.START_ARRAY` or `JsonToken.START_OBJECT` entries in output content. If enabled, such Array(s) and/or Object(s) are automatically closed; if disabled, nothing specific is done.

      Feature is enabled by default.

    - #### FLUSH_PASSED_TO_STREAM

          public static final JsonGenerator.Feature FLUSH_PASSED_TO_STREAM

      Feature that specifies that calls to `JsonGenerator.flush()` will cause matching `flush()` to underlying `OutputStream` or `Writer`; if disabled this will not be done. Main reason to disable this feature is to prevent flushing at generator level, if it is not possible to prevent method being called by other code (like `ObjectMapper` or third party libraries).

      Feature is enabled by default.

    - #### QUOTE_FIELD_NAMES

          public static final JsonGenerator.Feature QUOTE_FIELD_NAMES

      Feature that determines whether JSON Object field names are quoted using double-quotes, as specified by JSON specification or not. Ability to disable quoting was added to support use cases where they are not usually expected, which most commonly occurs when used straight from Javascript.

      Feature is enabled by default (since it is required by JSON specification).

    - #### QUOTE_NON_NUMERIC_NUMBERS

          public static final JsonGenerator.Feature QUOTE_NON_NUMERIC_NUMBERS

      Feature that determines whether "exceptional" (not real number) float/double values are output as quoted strings. The values checked are Double.Nan, Double.POSITIVE_INFINITY and Double.NEGATIVE_INIFINTY (and associated Float values). If feature is disabled, these numbers are still output using associated literal values, resulting in non-conformant output.

      Feature is enabled by default.

    - #### WRITE_NUMBERS_AS_STRINGS

          public static final JsonGenerator.Feature WRITE_NUMBERS_AS_STRINGS

      Feature that forces all Java numbers to be written as JSON strings. Default state is 'false', meaning that Java numbers are to be serialized using basic numeric serialization (as JSON numbers, integral or floating point). If enabled, all such numeric values are instead written out as JSON Strings.

      One use case is to avoid problems with Javascript limitations: since Javascript standard specifies that all number handling should be done using 64-bit IEEE 754 floating point values, result being that some 64-bit integer values can not be accurately represent (as mantissa is only 51 bit wide).

      Feature is disabled by default.

    - #### WRITE_BIGDECIMAL_AS_PLAIN

          public static final JsonGenerator.Feature WRITE_BIGDECIMAL_AS_PLAIN

      Feature that determines whether `BigDecimal` entries are serialized using `BigDecimal.toPlainString()` to prevent values to be written using scientific notation.

      Feature is disabled by default, so default output mode is used; this generally depends on how `BigDecimal` has been created.

      Since:
        2.3

    - #### ESCAPE_NON_ASCII

          public static final JsonGenerator.Feature ESCAPE_NON_ASCII

      Feature that specifies that all characters beyond 7-bit ASCII range (i.e. code points of 128 and above) need to be output using format-specific escapes (for JSON, backslash escapes), if format uses escaping mechanisms (which is generally true for textual formats but not for binary formats).

      Note that this setting may not necessarily make sense for all data formats (for example, binary formats typically do not use any escaping mechanisms; and some textual formats do not have general-purpose escaping); if so, settings is simply ignored. Put another way, effects of this feature are data-format specific.

      Feature is disabled by default.

    - #### STRICT_DUPLICATE_DETECTION

          public static final JsonGenerator.Feature STRICT_DUPLICATE_DETECTION

      Feature that determines whether `JsonGenerator` will explicitly check that no duplicate JSON Object field names are written. If enabled, generator will check all names within context and report duplicates by throwing a `JsonGenerationException`; if disabled, no such checking will be done. Assumption in latter case is that caller takes care of not trying to write duplicate names.

      Note that enabling this feature will incur performance overhead due to having to store and check additional information.

      Feature is disabled by default.

      Since:
        2.3

    - #### IGNORE_UNKNOWN

          public static final JsonGenerator.Feature IGNORE_UNKNOWN

      Feature that determines what to do if the underlying data format requires knowledge of all properties to output, and if no definition is found for a property that caller tries to write. If enabled, such properties will be quietly ignored; if disabled, a `JsonProcessingException` will be thrown to indicate the problem. Typically most textual data formats do NOT require schema information (although some do, such as CSV), whereas many binary data formats do require definitions (such as Avro, protobuf), although not all (Smile, CBOR, BSON and MessagePack do not).

      Note that support for this feature is implemented by individual data format module, if (and only if) it makes sense for the format in question. For JSON, for example, this feature has no effect as properties need not be pre-defined.

      Feature is disabled by default, meaning that if the underlying data format requires knowledge of all properties to output, attempts to write an unknown property will result in a `JsonProcessingException`

      Since:
        2.5

  - ### Method Detail

    - #### values

          public static JsonGenerator.Feature[] 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 (JsonGenerator.Feature c : JsonGenerator.Feature.values())
              System.out.println(c);

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

    - #### valueOf

          public static JsonGenerator.Feature valueOf(java.lang.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:
        `java.lang.IllegalArgumentException` - if this enum type has no constant with the specified name
        `java.lang.NullPointerException` - if the argument is null

    - #### collectDefaults

          public static int collectDefaults()

      Method that calculates bit set (flags) of all features that are enabled by default.

    - #### enabledByDefault

          public boolean enabledByDefault()

    - #### enabledIn

          public boolean enabledIn(int flags)

      Since:
        2.3

    - #### getMask

          public int getMask()