com.whitestein.lsps.vaadin.ui.components.table.dataset

Class DataDataset

java.lang.Object

com.whitestein.lsps.vaadin.ui.components.table.dataset.DataDataset

All Implemented Interfaces:

IDataset

public class DataDataset
extends Object
implements IDataset

Invokes a closure which takes two arguments (start, count) and returns a list of objects as a result. This class performs no sorting and filtering - sorting and filtering is performed in the closure itself. Therefore do not wrap this dataset in InMemoryDatasetFilter.

Author:

mvy

Constructor Summary

Constructors

Constructor and Description
DataDataset(Variant.ScopedClosureVariant dataClosure, Variant.ScopedClosureVariant dataCountClosure) Creates the dataset.

Method Summary

Modifier and Type	Method and Description
Type	getItemType() Returns the type of data returned by the load functions.
boolean	isFilterSupported(Filter filter) True if given filter criterion is supported.
boolean	isSortSupported(ISort criterion) True if given sort criterion is supported.
List<Object>	load(int startIndex, int count) Load batch of items, mostly records or simple types.
void	setFilter(Set<Filter> filters) Sets the new filtering criteria.
void	setSort(SortSpec sort) Sets the new sorting criteria.
int	size() Gets number of items available through this query.

Methods inherited from class java.lang.Object

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

Constructor Detail

DataDataset

public DataDataset(Variant.ScopedClosureVariant dataClosure,
                   Variant.ScopedClosureVariant dataCountClosure)

Creates the dataset.

Parameters:

dataClosure - the data providing closure, must have two parameters: start and count. Not null, must be present.

dataCountClosure - a parameterless closure which provides data count. Not null, must be present.

Method Detail

size

public int size()

Description copied from interface: IDataset

Gets number of items available through this query.

Specified by:

size in interface IDataset

Returns:

Number of items. Only count items which pass filters.

load

public List<Object> load(int startIndex,
                         int count)

Description copied from interface: IDataset

Load batch of items, mostly records or simple types. The items must be sorted and filtered accordingly, as stated by last call to IDataset.setSort(SortSpec) and/or IDataset.setFilter(java.util.Set) respectively.

Specified by:

load in interface IDataset

Parameters:

startIndex - Starting index of the item list, must be 0 or greater.

count - Count of the items to be retrieved, must be 0 or greater.

Returns:

List of items, mostly RecordHolders. Should never fail with out of bounds exception - if the startIndex or count is out of bounds, the item is simply not returned. The list may or may not be mutable.

setSort

public void setSort(SortSpec sort)

Description copied from interface: IDataset

Sets the new sorting criteria. This class should sort based on concrete implementations of ISort and must ignore sort criteria classes of unknown/unsupported types. Next call to IDataset.load(int, int) must return sorted filtered data.

Specified by:

setSort in interface IDataset

Parameters:

sort - the sorting criteria, not null.

setFilter

public void setFilter(Set<Filter> filters)

Description copied from interface: IDataset

Sets the new filtering criteria. This class should filter based on concrete implementations of ISort and must ignore filter criteria classes of unknown/unsupported types. Next call to IDataset.load(int, int) must return properly filtered data.

Specified by:

setFilter in interface IDataset

Parameters:

filters - the filtering criteria, not null, may be empty. Silently ignore unsupported filters.

isSortSupported

public boolean isSortSupported(ISort criterion)

Description copied from interface: IDataset

True if given sort criterion is supported.

Specified by:

isSortSupported in interface IDataset

Parameters:

criterion - the criterion, not null.

Returns:

true if given sort criterion is supported, false if not.

isFilterSupported

public boolean isFilterSupported(Filter filter)

Description copied from interface: IDataset

True if given filter criterion is supported.

Specified by:

isFilterSupported in interface IDataset

Parameters:

filter - the filter, not null.

Returns:

true if given filter is supported, false if not.

getItemType

public Type getItemType()

Description copied from interface: IDataset

Returns the type of data returned by the load functions. Returns Object if the type cannot be guessed.

Specified by:

getItemType in interface IDataset

Returns:

the type, never null.