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

Class GroupingDataset

java.lang.Object

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

All Implemented Interfaces:

IDataset

public class GroupingDataset
extends Object
implements IDataset

A very special dataset which allows for grouping of the records into groups, subgroups etc. The grouping and group sorting is performed in-memory.

Author:

mvy

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GroupingDataset.ClosureGroup
static class	GroupingDataset.Group
class	GroupingDataset.GroupNode
static class	GroupingDataset.LineResolvingGroup
static class	GroupingDataset.OptClosureGroup
static class	GroupingDataset.PropertyGroup
static interface	GroupingDataset.Reduction Reduction function to be performed over grouped items.

Constructor Summary

Constructors

Constructor and Description
GroupingDataset(IDataset delegate, GroupingDataset.Reduction reduction, boolean showWarnings) Creates the grouping 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.
GroupingDataset.GroupNode	load() Loads all data from the underlying dataset, groups it and returns it.
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	setGroupList(List<GroupingDataset.Group> groupList) Sets the new grouping 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

GroupingDataset

public GroupingDataset(IDataset delegate,
                       GroupingDataset.Reduction reduction,
                       boolean showWarnings)

Creates the grouping dataset.

Parameters:

delegate - provides data for this dataset. Must not be an instance of GroupingDataset. Not null.

reduction - the reduction function which computes data for aggregate rows, not null.

showWarnings - if true, a warning is logged to stdout when in-memory sorting/filtering of 500 or more items is performed.

Method Detail

setGroupList

public void setGroupList(List<GroupingDataset.Group> groupList)

Sets the new grouping criteria. Next call to load() must return properly grouped, sorted and filtered data.

Parameters:

groupList - the group list, not null, may be empty. First, the result list is grouped by the first group, then the sublists are grouped by the second group, etc.

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.

load

public GroupingDataset.GroupNode load()

Loads all data from the underlying dataset, groups it and returns it.

Returns:

the root group node, never null.