Package com.mckoi.util

Class AbstractBlockIntegerList

  • All Implemented Interfaces:
    IntegerListInterface
    Direct Known Subclasses:
    BlockIntegerList
    public abstract class AbstractBlockIntegerList
extends java.lang.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 java.util.ArrayList block_list
      The list of blocks (objects in this list are of type 'IntegerListBlockInterface'.

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      void add​(int val)
      Adds an int to the end of the list.
      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)  
      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.
      boolean contains​(java.lang.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.
      int get​(int pos)
      Returns the int at the given position in the list.
      void insertSort​(int val)
      Inserts plain 'int' values into the list in sorted order.
      void insertSort​(java.lang.Object key, int val, IndexComparator c)
      Inserts the key/index pair into the list at the correct sorted position (determine by the IndexComparator).
      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.
      int remove​(int pos)
      Removes an int from the given position in the list.
      protected int removeFromBlock​(int block_index, IntegerListBlockInterface block, int position)
      Removes the value from the given position in the specified block.
      boolean removeSort​(int val)
      Removes a plain 'int' value from the sorted position in the list only if it's already in the list.
      int removeSort​(java.lang.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.
      int searchFirst​(java.lang.Object key, IndexComparator c)
      Returns the index of the first value in this set that equals the given value.
      int searchLast​(java.lang.Object key, IndexComparator c)
      Returns the index of the last value in this set that equals the given value.
      void setImmutable()
      Sets the list as immutable (we aren't allowed to change the contents).
      int size()
      The number of integers that are in the list.
      java.lang.String toString()  
      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 Detail

      • block_list

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

    • Constructor Detail

      • 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 Detail

      • 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​(java.lang.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​(java.lang.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​(java.lang.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​(java.lang.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​(java.lang.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 java.lang.String toString()
        Overrides:
        toString in class java.lang.Object