com.mckoi.util
Class AbstractBlockIntegerList

java.lang.Object
  extended by com.mckoi.util.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
protected  java.util.ArrayList block_list
          The list of blocks (objects in this list are of type 'IntegerListBlockInterface'.
 
Constructor Summary
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
 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

checkSorted

public void checkSorted(IndexComparator c)

checkSorted

public static void checkSorted(IntegerIterator iterator,
                               IndexComparator c)