Package gnu.trove.list.linked

Class TLinkedList<T extends TLinkable<T>>

java.lang.Object
java.util.AbstractCollection<T>
java.util.AbstractList<T>
java.util.AbstractSequentialList<T>
gnu.trove.list.linked.TLinkedList<T>
All Implemented Interfaces:
Externalizable, Serializable, Iterable<T>, Collection<T>, List<T>, SequencedCollection<T>
public class TLinkedList<T extends TLinkable<T>> extends AbstractSequentialList<T> implements Externalizable

A LinkedList implementation which holds instances of type TLinkable. Using this implementation allows you to get java.util.LinkedList behavior (a doubly linked list, with Iterators that support insert and delete operations) without incurring the overhead of creating Node wrapper objects for every element in your list.
The requirement to achieve this time/space gain is that the Objects stored in the List implement the TLinkable interface.
The limitations are:

  • the same object cannot be put into more than one list at the same time.
  • the same object cannot be put into the same list more than once at the same time.
  • objects must only be removed from list they are in. That is, if you have an object A and lists l1 and l2, you must ensure that you invoke List.remove(A) on the correct list.
  • It is also forbidden to invoke List.remove() with an unaffiliated TLinkable (one that belongs to no list): this will destroy the list you invoke it on.
See Also:

  • Field Details

    • _head

      protected T extends TLinkable<T> _head
      the head of the list

    • _tail

      protected T extends TLinkable<T> _tail
      the tail of the list

    • _size

      protected int _size
      the number of elements in the list

  • Constructor Details

    • TLinkedList

      public TLinkedList()
      Creates a new TLinkedList instance.

  • Method Details

    • listIterator

      public ListIterator<T> listIterator(int index)
      Returns an iterator positioned at index. Assuming that the list has a value at that index, calling next() will retrieve and advance the iterator. Assuming that there is a value before index in the list, calling previous() will retrieve it (the value at index - 1) and move the iterator to that position. So, iterating from front to back starts at 0; iterating from back to front starts at size().
      Specified by:
      listIterator in interface List<T extends TLinkable<T>>
      Specified by:
      listIterator in class AbstractSequentialList<T extends TLinkable<T>>
      Parameters:
      index - an int value
      Returns:
      a ListIterator value

    • size

      public int size()
      Returns the number of elements in the list.
      Specified by:
      size in interface Collection<T extends TLinkable<T>>
      Specified by:
      size in interface List<T extends TLinkable<T>>
      Specified by:
      size in class AbstractCollection<T extends TLinkable<T>>
      Returns:
      an int value

    • add

      public void add(int index, T linkable)
      Inserts linkable at index index in the list. All values > index are shifted over one position to accommodate the new addition.
      Specified by:
      add in interface List<T extends TLinkable<T>>
      Overrides:
      add in class AbstractSequentialList<T extends TLinkable<T>>
      Parameters:
      index - an int value
      linkable - an object of type TLinkable

    • add

      public boolean add(T linkable)
      Appends linkable to the end of the list.
      Specified by:
      add in interface Collection<T extends TLinkable<T>>
      Specified by:
      add in interface List<T extends TLinkable<T>>
      Overrides:
      add in class AbstractList<T extends TLinkable<T>>
      Parameters:
      linkable - an object of type TLinkable
      Returns:
      always true

    • addFirst

      public void addFirst(T linkable)
      Inserts linkable at the head of the list.
      Specified by:
      addFirst in interface List<T extends TLinkable<T>>
      Specified by:
      addFirst in interface SequencedCollection<T extends TLinkable<T>>
      Parameters:
      linkable - an object of type TLinkable

    • addLast

      public void addLast(T linkable)
      Adds linkable to the end of the list.
      Specified by:
      addLast in interface List<T extends TLinkable<T>>
      Specified by:
      addLast in interface SequencedCollection<T extends TLinkable<T>>
      Parameters:
      linkable - an object of type TLinkable

    • clear

      public void clear()
      Empties the list.
      Specified by:
      clear in interface Collection<T extends TLinkable<T>>
      Specified by:
      clear in interface List<T extends TLinkable<T>>
      Overrides:
      clear in class AbstractList<T extends TLinkable<T>>

    • toArray

      public Object[] toArray()
      Copies the list's contents into a native array. This will be a shallow copy: the Tlinkable instances in the Object[] array have links to one another: changing those will put this list into an unpredictable state. Holding a reference to one element in the list will prevent the others from being garbage collected unless you clear the next/previous links. Caveat programmer!
      Specified by:
      toArray in interface Collection<T extends TLinkable<T>>
      Specified by:
      toArray in interface List<T extends TLinkable<T>>
      Overrides:
      toArray in class AbstractCollection<T extends TLinkable<T>>
      Returns:
      an Object[] value

    • toUnlinkedArray

      public Object[] toUnlinkedArray()
      Copies the list to a native array, destroying the next/previous links as the copy is made. This list will be emptied after the copy (as if clear() had been invoked). The Object[] array returned will contain TLinkables that do not hold references to one another and so are less likely to be the cause of memory leaks.
      Returns:
      an Object[] value

    • toUnlinkedArray

      public T[] toUnlinkedArray(T[] a)
      Returns a typed array of the objects in the set.
      Parameters:
      a - an Object[] value
      Returns:
      an Object[] value

    • contains

      public boolean contains(Object o)
      A linear search for o in the list.
      Specified by:
      contains in interface Collection<T extends TLinkable<T>>
      Specified by:
      contains in interface List<T extends TLinkable<T>>
      Overrides:
      contains in class AbstractCollection<T extends TLinkable<T>>
      Parameters:
      o - an Object value
      Returns:
      a boolean value

    • get

      public T get(int index)
      Specified by:
      get in interface List<T extends TLinkable<T>>
      Overrides:
      get in class AbstractSequentialList<T extends TLinkable<T>>

    • getFirst

      public T getFirst()
      Returns the head of the list
      Specified by:
      getFirst in interface List<T extends TLinkable<T>>
      Specified by:
      getFirst in interface SequencedCollection<T extends TLinkable<T>>
      Returns:
      an Object value

    • getLast

      public T getLast()
      Returns the tail of the list.
      Specified by:
      getLast in interface List<T extends TLinkable<T>>
      Specified by:
      getLast in interface SequencedCollection<T extends TLinkable<T>>
      Returns:
      an Object value

    • getNext

      public T getNext(T current)
      Return the node following the given node. This method exists for two reasons:
      1. It's really not recommended that the methods implemented by TLinkable be called directly since they're used internally by this class.
      2. This solves problems arising from generics when working with the linked objects directly.
      NOTE: this should only be used with nodes contained in the list. The results are undefined with anything else.
      Parameters:
      current - The current node
      Returns:
      the node after the current node

    • getPrevious

      public T getPrevious(T current)
      Return the node preceding the given node. This method exists for two reasons:
      1. It's really not recommended that the methods implemented by TLinkable be called directly since they're used internally by this class.
      2. This solves problems arising from generics when working with the linked objects directly.
      NOTE: this should only be used with nodes contained in the list. The results are undefined with anything else.
      Parameters:
      current - The current node
      Returns:
      the node after the current node

    • removeFirst

      public T removeFirst()
      Remove and return the first element in the list.
      Specified by:
      removeFirst in interface List<T extends TLinkable<T>>
      Specified by:
      removeFirst in interface SequencedCollection<T extends TLinkable<T>>
      Returns:
      an Object value

    • removeLast

      public T removeLast()
      Remove and return the last element in the list.
      Specified by:
      removeLast in interface List<T extends TLinkable<T>>
      Specified by:
      removeLast in interface SequencedCollection<T extends TLinkable<T>>
      Returns:
      an Object value

    • insert

      protected void insert(int index, T linkable)
      Implementation of index-based list insertions.
      Parameters:
      index - an int value
      linkable - an object of type TLinkable

    • remove

      public boolean remove(Object o)
      Removes the specified element from the list. Note that it is the caller's responsibility to ensure that the element does, in fact, belong to this list and not another instance of TLinkedList.
      Specified by:
      remove in interface Collection<T extends TLinkable<T>>
      Specified by:
      remove in interface List<T extends TLinkable<T>>
      Overrides:
      remove in class AbstractCollection<T extends TLinkable<T>>
      Parameters:
      o - a TLinkable element already inserted in this list.
      Returns:
      true if the element was a TLinkable and removed

    • addBefore

      public void addBefore(T current, T newElement)
      Inserts newElement into the list immediately before current. All elements to the right of and including current are shifted over.
      Parameters:
      current - a TLinkable value currently in the list.
      newElement - a TLinkable value to be added to the list.

    • addAfter

      public void addAfter(T current, T newElement)
      Inserts newElement into the list immediately after current. All elements to the left of and including current are shifted over.
      Parameters:
      current - a TLinkable value currently in the list.
      newElement - a TLinkable value to be added to the list.

    • forEachValue

      public boolean forEachValue(TObjectProcedure<T> procedure)
      Executes procedure for each entry in the list.
      Parameters:
      procedure - a TObjectProcedure value
      Returns:
      false if the loop over the values terminated because the procedure returned false for some value.

    • writeExternal

      public void writeExternal(ObjectOutput out) throws IOException
      Specified by:
      writeExternal in interface Externalizable
      Throws:
      IOException

    • readExternal

      public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
      Specified by:
      readExternal in interface Externalizable
      Throws:
      IOException
      ClassNotFoundException