Package com.tangosol.util

Class NullImplementation.NullSet

java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractSet
com.tangosol.util.NullImplementation.NullSet
All Implemented Interfaces:
ExternalizableLite, PortableObject, Serializable, Iterable, Collection, Set
Enclosing class:
NullImplementation
public static class NullImplementation.NullSet extends AbstractSet implements Serializable, ExternalizableLite, PortableObject
An immutable set which contains nothing.
See Also:

  • Field Details

    • INSTANCE

      public static final Set INSTANCE
      Since the set contains no information, only one ever has to exist.

  • Constructor Details

    • NullSet

      public NullSet()
      Default constructor (for ExternalizableLite and PortableObject).

  • Method Details

    • toArray

      public Object[] toArray()
      Returns an array containing all of the elements in this Set. Obeys the general contract of Collection.toArray.
      Specified by:
      toArray in interface Collection
      Specified by:
      toArray in interface Set
      Overrides:
      toArray in class AbstractCollection
      Returns:
      an Object array containing all of the elements in this Set

    • iterator

      public Iterator iterator()
      Returns an Iterator over the elements contained in this Collection.
      Specified by:
      iterator in interface Collection
      Specified by:
      iterator in interface Iterable
      Specified by:
      iterator in interface Set
      Specified by:
      iterator in class AbstractCollection
      Returns:
      an Iterator over the elements contained in this Collection

    • size

      public int size()
      Returns the number of elements in this Collection.
      Specified by:
      size in interface Collection
      Specified by:
      size in interface Set
      Specified by:
      size in class AbstractCollection
      Returns:
      the number of elements in this Collection

    • contains

      public boolean contains(Object o)
      Returns true if this Collection contains the specified element. More formally, returns true if and only if this Collection contains at least one element e such that (o==null ? e==null : o.equals(e)).
      Specified by:
      contains in interface Collection
      Specified by:
      contains in interface Set
      Overrides:
      contains in class AbstractCollection
      Parameters:
      o - the object to search for in the set
      Returns:
      true if this set contains the specified object

    • add

      public boolean add(Object o)
      Ensures that this Collection contains the specified element.
      Specified by:
      add in interface Collection
      Specified by:
      add in interface Set
      Overrides:
      add in class AbstractCollection
      Parameters:
      o - element whose presence in this Collection is to be ensured
      Returns:
      true if the Collection changed as a result of the call

    • remove

      public boolean remove(Object o)
      Removes a single instance of the specified element from this Collection, if it is present (optional operation). More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if the Collection contains one or more such elements. Returns true if the Collection contained the specified element (or equivalently, if the Collection changed as a result of the call).
      Specified by:
      remove in interface Collection
      Specified by:
      remove in interface Set
      Overrides:
      remove in class AbstractCollection
      Parameters:
      o - element to be removed from this Collection, if present
      Returns:
      true if the Collection contained the specified element

    • clear

      public void clear()
      Removes all of the elements from this Collection.
      Specified by:
      clear in interface Collection
      Specified by:
      clear in interface Set
      Overrides:
      clear in class AbstractCollection

    • equals

      public boolean equals(Object o)
      Specified by:
      equals in interface Collection
      Specified by:
      equals in interface Set
      Overrides:
      equals in class AbstractSet

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Collection
      Specified by:
      hashCode in interface Set
      Overrides:
      hashCode in class AbstractSet

    • readExternal

      public void readExternal(DataInput in) throws IOException
      Restore the contents of this object by loading the object's state from the passed DataInput object.
      Specified by:
      readExternal in interface ExternalizableLite
      Parameters:
      in - the DataInput stream to read data from in order to restore the state of this object
      Throws:
      IOException - if an I/O exception occurs
      NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

    • writeExternal

      public void writeExternal(DataOutput out) throws IOException
      Save the contents of this object by storing the object's state into the passed DataOutput object.
      Specified by:
      writeExternal in interface ExternalizableLite
      Parameters:
      out - the DataOutput stream to write the state of this object to
      Throws:
      IOException - if an I/O exception occurs

    • readExternal

      public void readExternal(PofReader in) throws IOException
      Restore the contents of a user type instance by reading its state using the specified PofReader object.
      Specified by:
      readExternal in interface PortableObject
      Parameters:
      in - the PofReader from which to read the object's state
      Throws:
      IOException - if an I/O error occurs

    • writeExternal

      public void writeExternal(PofWriter out) throws IOException
      Save the contents of a POF user type instance by writing its state using the specified PofWriter object.
      Specified by:
      writeExternal in interface PortableObject
      Parameters:
      out - the PofWriter to which to write the object's state
      Throws:
      IOException - if an I/O error occurs