Class Alias

java.lang.Object
org.springframework.data.mapping.Alias
public final class Alias extends Object
A container object which may or may not contain a type alias value. If a value is present, isPresent() will return true and getValue() will return the value.

Additional methods that depend on the presence or absence of a contained value are provided, such as hasValue(Object) or isPresent()

Aliases are immutable once created.

Author:
Oliver Gierke, Christoph Strobl, Mark Paluch

  • Field Details

    • NONE

      public static final Alias NONE
      Common instance for empty().

  • Method Details

    • of

      public static Alias of(Object alias)
      Create an Alias given the alias object.
      Parameters:
      alias - must not be null.
      Returns:
      the Alias for alias.

    • ofNullable

      public static Alias ofNullable(@Nullable Object alias)
      Create an Alias from a possibly present alias object. Using a null alias will return empty().
      Parameters:
      alias - may be null.
      Returns:
      the Alias for alias or empty() if the given alias was null.

    • empty

      public static Alias empty()
      Returns an empty Alias instance. No value is present for this Alias.
      Returns:
      an empty Alias.

    • isPresentButDifferent

      public boolean isPresentButDifferent(Alias other)
      Checks whether this Alias has a value but is different from the other value.
      Parameters:
      other - must not be null.
      Returns:
      true if this value is present but different from the other value.

    • hasValue

      public boolean hasValue(Object that)
      Checks whether this Alias contains the value that.
      Parameters:
      that - the other value, may be null.
      Returns:
      true if this alias has a value and it equals to that.

    • hasSamePresentValueAs

      public boolean hasSamePresentValueAs(Alias other)
      Returns whether the current alias is present and has the same value as the given Alias.
      Parameters:
      other - the other Alias
      Returns:
      true if there's an alias value present and its equal to the one in the given Alias.

    • isPresent

      public boolean isPresent()
      Returns:
      true if this Alias contains a value.

    • isEmpty

      public boolean isEmpty()
      Returns:
      true if this Alias does not contain a value.
      Since:
      4.0

    • mapTyped

      public <T> @Nullable T mapTyped(Class<T> type)
      Return the value typed to type if the value is present and assignable to type.
      Parameters:
      type - must not be null.
      Returns:

    • getValue

      public @Nullable Object getValue()

    • getRequiredValue

      public Object getRequiredValue()
      Retrieve the required value or throw NoSuchElementException if the value is absent.
      Returns:
      the required value.

    • equals

      public boolean equals(@Nullable Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object