java.lang.Object
- org.openrefine.browsing.Engine

```
public class Engine
extends Object
```
Faceted browsing engine. Given a Grid and facet configurations, it can be used to compute facet statistics and obtain a filtered view of the grid according to the facets.
It also computes datatype statistics for each column, serialized in the "columnStats" JSON field.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Engine.Mode

Field Summary

Fields
Modifier and Type	Field	Description
`protected EngineConfig`	`_config`
`protected List<Facet>`	`_facets`
`protected Grid.PartialAggregation<AllFacetsState>`	`_facetsState`
`protected Grid`	`_state`
`static String`	`INCLUDE_DEPENDENT`
`static String`	`MODE`
`static String`	`MODE_RECORD_BASED`
`static String`	`MODE_ROW_BASED`

Constructor Summary

Constructors
Constructor Description

Engine(Grid state, EngineConfig config, long projectId)

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`<T extends Serializable> T`	`aggregateFilteredRecords(RecordAggregator<T> aggregator, T initialState)`	Runs an aggregator only on the records that are selected by facets.
`<T extends Serializable> T`	`aggregateFilteredRows(RowAggregator<T> aggregator, T initialState)`	Runs an aggregator only on the rows that are selected by facets.
`RecordFilter`	`combinedRecordFilters()`
`RowFilter`	`combinedRowFilters()`
`long`	`getAggregatedCount()`	Number of rows on which the facets were actually checked.
`List<ColumnStats>`	`getColumnStats()`	Some statistics for each column: reconciliation and data type statistics.
`EngineConfig`	`getConfig()`
`com.google.common.collect.ImmutableList<FacetResult>`	`getFacetResults()`	The state of the computed facets.
`protected Grid.PartialAggregation<AllFacetsState>`	`getFacetsState()`
`long`	`getFilteredCount()`	Number of rows in the filtered grid, among those which have been checked (`getAggregatedCount()`).
`Grid`	`getGrid()`
`CloseableIterator<Record>`	`getMatchingRecords(SortingConfig sortingConfig)`	Iterates over the records matched by the given filters.
`CloseableIterator<IndexedRow>`	`getMatchingRows(SortingConfig sortingConfig)`	Iterates over the rows matched by the given filters.
`Engine.Mode`	`getMode()`
`long`	`getTotalCount()`	Total number of rows/records in the unfiltered grid
`long`	`getTotalRows()`	Total number of rows in the unfiltered grid (needed to provide a link to the last page)
`boolean`	`isNeutral()`	True when all the facets are in a neutral state, meaning that they do not filter out any row or record.
`boolean`	`limitReached()`	True when the aggregation stopped because of the imposed aggregation limit, in which case statistics such as `getFilteredCount()` should be understood relative to `getAggregatedCount()`.
`static String`	`modeToString(Engine.Mode mode)`
`static Engine.Mode`	`stringToMode(String s)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INCLUDE_DEPENDENT
```
public static final String INCLUDE_DEPENDENT
```
    See Also:
    
    Constant Field Values
  - MODE
```
public static final String MODE
```
    See Also:
    
    Constant Field Values
  - MODE_ROW_BASED
```
public static final String MODE_ROW_BASED
```
    See Also:
    
    Constant Field Values
  - MODE_RECORD_BASED
```
public static final String MODE_RECORD_BASED
```
    See Also:
    
    Constant Field Values
  - _state
```
protected final Grid _state
```
  - _facets
```
protected final List<Facet> _facets
```
  - _config
```
protected final EngineConfig _config
```
  - _facetsState
```
protected Grid.PartialAggregation<AllFacetsState> _facetsState
```
- Constructor Detail
  - Engine
```
public Engine(Grid state,
              EngineConfig config,
              long projectId)
```
- Method Detail
  - modeToString
```
public static String modeToString(Engine.Mode mode)
```
  - stringToMode
```
public static Engine.Mode stringToMode(String s)
```
  - getMode
```
public Engine.Mode getMode()
```
  - getGrid
```
public Grid getGrid()
```
  - getConfig
```
public EngineConfig getConfig()
```
  - getFacetsState
```
protected Grid.PartialAggregation<AllFacetsState> getFacetsState()
```
  - getFacetResults
```
public com.google.common.collect.ImmutableList<FacetResult> getFacetResults()
```
    The state of the computed facets.
  - isNeutral
```
public boolean isNeutral()
```
    True when all the facets are in a neutral state, meaning that they do not filter out any row or record.
  - getColumnStats
```
public List<ColumnStats> getColumnStats()
```
    Some statistics for each column: reconciliation and data type statistics.
  - getTotalCount
```
public long getTotalCount()
```
    Total number of rows/records in the unfiltered grid
  - getTotalRows
```
public long getTotalRows()
```
    Total number of rows in the unfiltered grid (needed to provide a link to the last page)
  - getAggregatedCount
```
public long getAggregatedCount()
```
    Number of rows on which the facets were actually checked. Can be less than getTotalCount() if the engine configuration capped the number of rows to process.
  - getFilteredCount
```
public long getFilteredCount()
```
    Number of rows in the filtered grid, among those which have been checked (getAggregatedCount()).
  - limitReached
```
public boolean limitReached()
```
    True when the aggregation stopped because of the imposed aggregation limit, in which case statistics such as getFilteredCount() should be understood relative to getAggregatedCount().
  - getMatchingRows
```
public CloseableIterator<IndexedRow> getMatchingRows(SortingConfig sortingConfig)
```
    Iterates over the rows matched by the given filters. If the engine is in records mode, the rows corresponding to the matching records are returned.
    
    Parameters:
    
    sortingConfig - in which order to iterate over rows
  - getMatchingRecords
```
public CloseableIterator<Record> getMatchingRecords(SortingConfig sortingConfig)
```
    Iterates over the records matched by the given filters. If the engine is in records mode, the rows corresponding to the matching records are returned.
    
    Parameters:
    
    sortingConfig - in which order to iterate over records
  - combinedRowFilters
```
public RowFilter combinedRowFilters()
```
    Returns:
    
    a row filter obtained from all applied facets
  - combinedRecordFilters
```
public RecordFilter combinedRecordFilters()
```
    Returns:
    
    a record filter obtained from all applied facets
  - aggregateFilteredRows
```
public <T extends Serializable> T aggregateFilteredRows(RowAggregator<T> aggregator,
                                                        T initialState)
```
    Runs an aggregator only on the rows that are selected by facets.
    
    Parameters:
    
    aggregator - the aggregator to run on the selected rows
    
    initialState - the initial state of the aggregator (which should act as neutral element)
  - aggregateFilteredRecords
```
public <T extends Serializable> T aggregateFilteredRecords(RecordAggregator<T> aggregator,
                                                           T initialState)
```
    Runs an aggregator only on the records that are selected by facets.
    
    Parameters:
    
    aggregator - the aggregator to run on the selected records
    
    initialState - the initial state of the aggregator (which should act as neutral element)

Class Engine

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INCLUDE_DEPENDENT

MODE

MODE_ROW_BASED

MODE_RECORD_BASED

_state

_facets

_config

_facetsState

Constructor Detail

Engine

Method Detail

modeToString

stringToMode

getMode

getGrid

getConfig

getFacetsState

getFacetResults

isNeutral

getColumnStats

getTotalCount

getTotalRows

getAggregatedCount

getFilteredCount

limitReached

getMatchingRows

getMatchingRecords

combinedRowFilters

combinedRecordFilters

aggregateFilteredRows

aggregateFilteredRecords