Java compact1, compact2, compact3 java.util.stream Enum Collector.Characteristics（JDK8）

Enum Constant Detail

• CONCURRENT

  public static final Collector.Characteristics CONCURRENT

  Indicates that this collector is concurrent, meaning that the result container can support the accumulator function being called concurrently with the same result container from multiple threads.

  If a CONCURRENT collector is not also UNORDERED, then it should only be evaluated concurrently if applied to an unordered data source.

• UNORDERED

  public static final Collector.Characteristics UNORDERED

  Indicates that the collection operation does not commit to preserving the encounter order of input elements. (This might be true if the result container has no intrinsic order, such as a Set.)

• IDENTITY_FINISH

  public static final Collector.Characteristics IDENTITY_FINISH

  Indicates that the finisher function is the identity function and can be elided. If set, it must be the case that an unchecked cast from A to R will succeed.

Method Detail

• values

  public static Collector.Characteristics[] 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 (Collector.Characteristics c : Collector.Characteristics.values())
      System.out.println(c);
  

  Returns:

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

• valueOf

  public static Collector.Characteristics 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