de.vc.util

Class LazyList<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

de.vc.util.LazyList<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.List<E>

Direct Known Subclasses:

LazyListWithLoader

public abstract class LazyList<E>
extends java.util.AbstractList<E>

A lazy list loads it's elements on demand using chunks. To use this class you must extends from LazyList and implement calculateSize and fillChunk.

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor and Description
LazyList() Creates a new lazy list with chunkSize=10 and chunkOffset=0.
LazyList(int chunkSize) Creates a new lazy list with a given chunkSize and chunkOffset=0.
LazyList(int chunkSize, int chunkOffset) Creates a new lazy list with a given chunkSize and chunkOffset.

Method Summary

Modifier and Type	Method and Description
protected abstract int	calculateSize() Implement this method to calculate the total size of this list.
protected abstract void	fillChunk(int start, int length) Implement this method to load a range of lazy loaded objects.
E	get(int index)
float	getGrowFactor()
int	getShrinkThreshold()
E	set(int index, E o) Sets a cached object.
void	setChunkParams(int size, int offset) Sets the chunk parameters.
void	setGrowFactor(float growFactor)
void	setShrinkThreshold(int shrinkThreshold)
protected void	setSize(int newSize) An implementing class can update the size of this list any time (e.g. if the size of a result set changed).
int	size()

Methods inherited from class java.util.AbstractList

add, add, addAll, clear, equals, hashCode, indexOf, iterator, lastIndexOf, listIterator, listIterator, remove, removeRange, subList

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

addAll, contains, containsAll, isEmpty, remove, removeAll, replaceAll, retainAll, sort, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

LazyList

public LazyList()

Creates a new lazy list with chunkSize=10 and chunkOffset=0.

LazyList

public LazyList(int chunkSize)

Creates a new lazy list with a given chunkSize and chunkOffset=0.

Parameters:

chunkSize - Size of a lazy loaded chunk.

LazyList

public LazyList(int chunkSize,
                int chunkOffset)

Creates a new lazy list with a given chunkSize and chunkOffset.

Parameters:

chunkSize - Size of a lazy loaded chunk.

chunkOffset - Offset of a lazy loaded chunk, must be 0 or negative.

Method Detail

get

public final E get(int index)

Specified by:

get in interface java.util.List<E>

Specified by:

get in class java.util.AbstractList<E>

size

public final int size()

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in interface java.util.List<E>

Specified by:

size in class java.util.AbstractCollection<E>

setChunkParams

public void setChunkParams(int size,
                           int offset)

Sets the chunk parameters.

Parameters:

size - Size of a lazy loaded chunk.

offset - Offset of a lazy loaded chunk, must be 0 or negative.

Throws:

java.lang.IllegalArgumentException

set

public E set(int index,
             E o)

Sets a cached object. This method should be invoked in fillChunk.

Specified by:

set in interface java.util.List<E>

Overrides:

set in class java.util.AbstractList<E>

Parameters:

index - Index

o - Object

getGrowFactor

public float getGrowFactor()

setGrowFactor

public void setGrowFactor(float growFactor)

getShrinkThreshold

public int getShrinkThreshold()

setShrinkThreshold

public void setShrinkThreshold(int shrinkThreshold)

setSize

protected void setSize(int newSize)

An implementing class can update the size of this list any time (e.g. if the size of a result set changed).

Parameters:

newSize -

calculateSize

protected abstract int calculateSize()

Implement this method to calculate the total size of this list.

Returns:

Size of list.

fillChunk

protected abstract void fillChunk(int start,
                                  int length)

Implement this method to load a range of lazy loaded objects. Use the set(int i, Object o) method to set a loaded object.

Parameters:

start - Start offset

length - Chunk length