org.apache.xml.utils
Class SuballocatedIntVector
java.lang.Object
org.apache.xml.utils.SuballocatedIntVector
public class SuballocatedIntVector
extends java.lang.Object
A very simple table that stores a list of int. Very similar API to our
IntVector class (same API); different internal storage.
This version uses an array-of-arrays solution. Read/write access is thus
a bit slower than the simple IntVector, and basic storage is a trifle
higher due to the top-level array -- but appending is O(1) fast rather
than O(N**2) slow, which will swamp those costs in situations where
long vectors are being built up.
Known issues:
Some methods are private because they haven't yet been tested properly.
Retrieval performance is critical, since this is used at the core
of the DTM model. (Append performance is almost as important.)
That's pushing me toward just letting reads from unset indices
throw exceptions or return stale data; safer behavior would have
performance costs.
void | addElement(int value) - Append a int onto the vector.
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int | elementAt(int i) - Get the nth element.
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int[][] | getMap() - Return the m_map double array
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int[] | getMap0() - Return the internal m_map0 array
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int | indexOf(int elem) - Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
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int | indexOf(int elem, int index) - Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
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void | removeAllElements() - Wipe it out.
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void | setElementAt(int value, int at) - Sets the component at the specified index of this vector to be the
specified object.
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void | setSize(int sz) - Set the length of the list.
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int | size() - Get the length of the list.
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SuballocatedIntVector
public SuballocatedIntVector()
Default constructor. Note that the default
block size is currently 2K, which may be overkill for
small lists and undershootng for large ones.
SuballocatedIntVector
public SuballocatedIntVector(int blocksize)
Construct a IntVector, using the given block size and
the default number of blocks (32).
blocksize
- Size of block to allocate
SuballocatedIntVector
public SuballocatedIntVector(int blocksize,
int numblocks)
Construct a IntVector, using the given block size and number
of blocks. For efficiency, we will round the requested size
off to a power of two.
blocksize
- Size of block to allocatenumblocks
- Number of blocks to allocate
addElement
public void addElement(int value)
Append a int onto the vector.
value
- Int to add to the list
elementAt
public int elementAt(int i)
Get the nth element. This is often at the innermost loop of an
application, so performance is critical.
i
- index of value to get
- value at given index. If that value wasn't previously set,
the result is undefined for performance reasons. It may throw an
exception (see below), may return zero, or (if setSize has previously
been used) may return stale data.
getMap
public final int[][] getMap()
Return the m_map double array
- the internal map of array of arrays
getMap0
public final int[] getMap0()
Return the internal m_map0 array
- the m_map0 array
indexOf
public int indexOf(int elem)
Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
elem
- object to look for
- the index of the first occurrence of the object
argument in this vector at position index or later in the
vector; returns -1 if the object is not found.
indexOf
public int indexOf(int elem,
int index)
Searches for the first occurence of the given argument,
beginning the search at index, and testing for equality
using the equals method.
elem
- object to look forindex
- Index of where to begin search
- the index of the first occurrence of the object
argument in this vector at position index or later in the
vector; returns -1 if the object is not found.
removeAllElements
public void removeAllElements()
Wipe it out. Currently defined as equivalent to setSize(0).
setElementAt
public void setElementAt(int value,
int at)
Sets the component at the specified index of this vector to be the
specified object. The previous component at that position is discarded.
The index must be a value greater than or equal to 0 and less
than the current size of the vector.
setSize
public void setSize(int sz)
Set the length of the list. This will only work to truncate the list, and
even then it has not been heavily tested and may not be trustworthy.
size
public int size()
Get the length of the list.
- length of the list
Copyright B) 2004 Apache XML Project. All Rights Reserved.