Package com.mckoi.util

Class AbstractBlockIntegerList

java.lang.Object
com.mckoi.util.AbstractBlockIntegerList
All Implemented Interfaces:
IntegerListInterface
Direct Known Subclasses:
BlockIntegerList
public abstract class AbstractBlockIntegerList extends Object implements IntegerListInterface
An implementation of a list of integer values that are stored across an array of blocks. This allows for quicker insertion and deletion of integer values, including other memory saving benefits.

The class works as follows;

  1. The list can contain any number of 'int' values.
  2. Each value is stored within a block of int's. A block is of finite size.
  3. When a block becomes full, int values are moved around until enough space is free. This may be by inserting a new block or by shifting information from one block to another.
  4. When a block becomes empty, it is removed.
The benefits of this system are that inserts and deletes are fast even for very large lists. There are no megabyte sized arraycopys. Also, the object could be extended to a version that pages un-used blocks to disk thus saving precious system memory.

NOTE: The following methods are NOT optimal: get(pos), add(val, pos), remove(pos)

Specifically, they slow as 'pos' nears the end of large lists.

This type of structure is very fast for large sorted lists where values can be inserted at any position within the list. Care needs to be taken for lists where values are inserted and removed constantly, because fragmentation of the list blocks can occur. For example, adding 60,000 random entries followed by removing 50,000 random entries will result in many only partially filled blocks. Since each block takes a constant amount of memory, this may not be acceptable.

Author:
Tobias Downer

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected ArrayList
    block_list
    The list of blocks (objects in this list are of type 'IntegerListBlockInterface'.

  • Constructor Summary

    Constructors
    Constructor
    Description
    AbstractBlockIntegerList()
    Constructs the list.
    AbstractBlockIntegerList(IntegerListBlockInterface[] blocks)
    Constructs the list from the given set of initial blocks.
    AbstractBlockIntegerList(IntegerListInterface i_list)
    Copies the information from the given BlockIntegerList into a new object and performs a deep clone of the information in this container.
    AbstractBlockIntegerList(IntegerVector ivec)
    Constructs the list by copying the contents from an IntegerVector.

  • Method Summary

    Modifier and Type
    Method
    Description
    final void
    add(int val)
    Adds an int to the end of the list.
    final void
    add(int val, int pos)
    Adds an int at the given position in the list.
    void
    checkSorted(IndexComparator c)
     
    static void
    checkSorted(IntegerIterator iterator, IndexComparator c)
     
    final boolean
    contains(int val)
    Assuming the list is sorted, this performs a binary search and returns true if the value is found, otherwise returns false.
    final boolean
    contains(Object key, IndexComparator c)
    Assuming the list is sorted, this performs a binary search and returns true if the value is found, otherwise returns false.
    protected void
    deleteListBlock(IntegerListBlockInterface list_block)
    Called when the class decides this ListBlock is no longer needed.
    final int
    get(int pos)
    Returns the int at the given position in the list.
    final void
    insertSort(int val)
    Inserts plain 'int' values into the list in sorted order.
    final void
    insertSort(Object key, int val, IndexComparator c)
    Inserts the key/index pair into the list at the correct sorted position (determine by the IndexComparator).
    final boolean
    isImmutable()
    Returns true if this interface is immutable.
    IntegerIterator
    iterator()
    Returns an IntegerIterator that will walk from the start to the end this list.
    IntegerIterator
    iterator(int start_offset, int end_offset)
    Returns an IntegerIterator that will walk from the start offset (inclusive) to the end offset (inclusive) of this list.
    protected abstract IntegerListBlockInterface
    newListBlock()
    Creates a new ListBlock for the given implementation.
    final int
    remove(int pos)
    Removes an int from the given position in the list.
    protected final int
    removeFromBlock(int block_index, IntegerListBlockInterface block, int position)
    Removes the value from the given position in the specified block.
    final boolean
    removeSort(int val)
    Removes a plain 'int' value from the sorted position in the list only if it's already in the list.
    final int
    removeSort(Object key, int val, IndexComparator c)
    Removes the key/val pair from the list by first searching for it, and then removing it from the list.
    final int
    searchFirst(Object key, IndexComparator c)
    Returns the index of the first value in this set that equals the given value.
    final int
    searchLast(Object key, IndexComparator c)
    Returns the index of the last value in this set that equals the given value.
    final void
    setImmutable()
    Sets the list as immutable (we aren't allowed to change the contents).
    final int
    size()
    The number of integers that are in the list.
    String
    toString()
     
    final boolean
    uniqueInsertSort(int val)
    Inserts plain 'int' value into the sorted position in the list only if it isn't already in the list.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Field Details

    • block_list

      protected ArrayList block_list
      The list of blocks (objects in this list are of type 'IntegerListBlockInterface'.

  • Constructor Details

    • AbstractBlockIntegerList

      public AbstractBlockIntegerList()
      Constructs the list.

    • AbstractBlockIntegerList

      public AbstractBlockIntegerList(IntegerListBlockInterface[] blocks)
      Constructs the list from the given set of initial blocks.

    • AbstractBlockIntegerList

      public AbstractBlockIntegerList(IntegerVector ivec)
      Constructs the list by copying the contents from an IntegerVector.

    • AbstractBlockIntegerList

      public AbstractBlockIntegerList(IntegerListInterface i_list)
      Copies the information from the given BlockIntegerList into a new object and performs a deep clone of the information in this container.

  • Method Details

    • newListBlock

      protected abstract IntegerListBlockInterface newListBlock()
      Creates a new ListBlock for the given implementation.

    • deleteListBlock

      protected void deleteListBlock(IntegerListBlockInterface list_block)
      Called when the class decides this ListBlock is no longer needed. Provided as an event for derived classes to intercept.

    • removeFromBlock

      protected final int removeFromBlock(int block_index, IntegerListBlockInterface block, int position)
      Removes the value from the given position in the specified block. It returns the value that used to be at that position.

    • setImmutable

      public final void setImmutable()
      Sets the list as immutable (we aren't allowed to change the contents).
      Specified by:
      setImmutable in interface IntegerListInterface

    • isImmutable

      public final boolean isImmutable()
      Returns true if this interface is immutable.
      Specified by:
      isImmutable in interface IntegerListInterface

    • size

      public final int size()
      The number of integers that are in the list.
      Specified by:
      size in interface IntegerListInterface

    • get

      public final int get(int pos)
      Returns the int at the given position in the list. NOTE: This is not a very fast routine. Certainly a lot slower than IntegerVector intAt.
      Specified by:
      get in interface IntegerListInterface

    • add

      public final void add(int val, int pos)
      Adds an int at the given position in the list.
      Specified by:
      add in interface IntegerListInterface

    • add

      public final void add(int val)
      Adds an int to the end of the list.
      Specified by:
      add in interface IntegerListInterface

    • remove

      public final int remove(int pos)
      Removes an int from the given position in the list. Returns the value that used to be at that position.
      Specified by:
      remove in interface IntegerListInterface

    • contains

      public final boolean contains(int val)
      Assuming the list is sorted, this performs a binary search and returns true if the value is found, otherwise returns false.

      We must supply a 'IndexComparator' for how the list is sorted.

      Specified by:
      contains in interface IntegerListInterface

    • insertSort

      public final void insertSort(int val)
      Inserts plain 'int' values into the list in sorted order.
      Specified by:
      insertSort in interface IntegerListInterface

    • uniqueInsertSort

      public final boolean uniqueInsertSort(int val)
      Inserts plain 'int' value into the sorted position in the list only if it isn't already in the list. If the value is inserted it returns true, otherwise if the value wasn't inserted because it's already in the list, it returns false.
      Specified by:
      uniqueInsertSort in interface IntegerListInterface

    • removeSort

      public final boolean removeSort(int val)
      Removes a plain 'int' value from the sorted position in the list only if it's already in the list. If the value is removed it returns true, otherwise if the value wasn't removed because it couldn't be found in the list, it returns false.
      Specified by:
      removeSort in interface IntegerListInterface

    • contains

      public final boolean contains(Object key, IndexComparator c)
      Assuming the list is sorted, this performs a binary search and returns true if the value is found, otherwise returns false.

      We must supply a 'IndexComparator' for how the list is sorted.

      Specified by:
      contains in interface IntegerListInterface

    • insertSort

      public final void insertSort(Object key, int val, IndexComparator c)
      Inserts the key/index pair into the list at the correct sorted position (determine by the IndexComparator). If the list already contains identical key then the value is put on the end of the set. This way, the sort is stable (the order of identical elements does not change).
      Specified by:
      insertSort in interface IntegerListInterface

    • removeSort

      public final int removeSort(Object key, int val, IndexComparator c)
      Removes the key/val pair from the list by first searching for it, and then removing it from the list.

      NOTE: There will be a list scan (bad performance) for the erronious case when the key/val pair is not present in the list.

      Specified by:
      removeSort in interface IntegerListInterface

    • searchLast

      public final int searchLast(Object key, IndexComparator c)
      Returns the index of the last value in this set that equals the given value.
      Specified by:
      searchLast in interface IntegerListInterface

    • searchFirst

      public final int searchFirst(Object key, IndexComparator c)
      Returns the index of the first value in this set that equals the given value.
      Specified by:
      searchFirst in interface IntegerListInterface

    • iterator

      public IntegerIterator iterator(int start_offset, int end_offset)
      Returns an IntegerIterator that will walk from the start offset (inclusive) to the end offset (inclusive) of this list.

      This iterator supports the 'remove' method.

      Specified by:
      iterator in interface IntegerListInterface

    • iterator

      public IntegerIterator iterator()
      Returns an IntegerIterator that will walk from the start to the end this list.

      This iterator supports the 'remove' method.

      Specified by:
      iterator in interface IntegerListInterface

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • checkSorted

      public void checkSorted(IndexComparator c)

    • checkSorted

      public static void checkSorted(IntegerIterator iterator, IndexComparator c)