org.dellroad.stuff.vaadin7

Class WindowQueryList<T>

java.lang.Object

org.dellroad.stuff.vaadin7.WindowQueryList<T>

All Implemented Interfaces:

QueryList<T>

public class WindowQueryList<T>
extends Object
implements QueryList<T>

QueryList implementation that only actually holds a portion, or "window" of a larger list. If a list element outside the "window" is accessed, an InvalidQueryListException is thrown, prompting another query.

See Also:

AbstractQueryContainer

Constructor Summary

Constructors

Constructor and Description
WindowQueryList(List<? extends T> list, int offset, int count) Constructor when the original list is given with window bounds.
WindowQueryList(long offset, List<? extends T> window, long totalSize) Constructor when a "window" list is given with its position in the original list.

Method Summary

Modifier and Type	Method and Description
T	get(long index) Get an item in the list, or throw an exception if this instance is no longer valid or cannot provide the item.
long	size() Get the total size of this list.

Methods inherited from class java.lang.Object

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

Constructor Detail

WindowQueryList

public WindowQueryList(List<? extends T> list,
                       int offset,
                       int count)

Constructor when the original list is given with window bounds.

Parameters:

list - original list from which to cache elements

offset - index in the list of the first element in the window

count - number of elements in the window

Throws:

IllegalArgumentException - if list is null

IllegalArgumentException - if offset and/or count are invalid

WindowQueryList

public WindowQueryList(long offset,
                       List<? extends T> window,
                       long totalSize)

Constructor when a "window" list is given with its position in the original list.

Parameters:

window - list of only those elements in the "window"

offset - offset of the "window" in the original list

totalSize - total size of the original list

Throws:

IllegalArgumentException - if window is null

IllegalArgumentException - if offset < 0

IllegalArgumentException - if offset + window.size() > totalSize

Method Detail

size

public long size()

Description copied from interface: QueryList

Get the total size of this list.

For any given QueryList instance, this method is expected to return a the same value if invoked multiple times. Therefore, callers may safely choose to invoke it only once on a given instance and cache the result.

Specified by:

size in interface QueryList<T>

Returns:

total size of list

get

public T get(long index)
      throws InvalidQueryListException

Description copied from interface: QueryList

Get an item in the list, or throw an exception if this instance is no longer valid or cannot provide the item.

Specified by:

get in interface QueryList<T>

Parameters:

index - index of the item (zero-based)

Returns:

the list item at index

Throws:

InvalidQueryListException - if this list has become invalid or cannot provide the item