Package org.apache.juneau.console.data

Class SeriesAggregator

java.lang.Object

org.apache.juneau.console.data.SeriesAggregator

public final class SeriesAggregator
extends Object

Answers a console data source's aggregate request in one pass over a row stream.

The request names a window, a bucket unit, up to three groupBy fields and the measures to compute. Any other query parameter is an app filter, returned untouched by SeriesAggregator.Request.filters() for the app's own row query. Fields used by groupBy or a measure must be allowed with allowFields(String...). A bad request throws SeriesAggregator.RequestException (HTTP 400, E-75). At most maxBuckets(int) result cells are kept; rows that would open another cell are dropped and the result is marked truncated.

A group value is the text of the row's value, or null (JSON null) when the row has none, so a missing value and the text "null" are different groups. The null group sorts first within its bucket.

Example:

@RestGet(path="/series/aggregate") public void aggregate(RestRequest req, RestResponse res) throws Exception { var q = SeriesAggregator.Request.from(req); try (var rows = svc.rows(q.start(), q.end(), q.filters())) { SeriesAggregator.create().timeField("start") .allowFields("status", "ms") .maxBuckets(10_000).aggregate(q, rows).writeTo(res); } }

Since:

10.0.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final class	SeriesAggregator.Request	A parsed aggregate request.
static final class	SeriesAggregator.RequestException	A rejected aggregate request: HTTP 400 with an E-75 message.
static final class	SeriesAggregator.Result	An aggregate result in columnar form: the dims, their types, and one value list per dim.

Method Summary

Modifier and Type	Method	Description
SeriesAggregator.Result	aggregate(SeriesAggregator.Request req, Stream<? extends SeriesSource.Row> rows)	Aggregates the rows in one pass.
SeriesAggregator	allowFields(String... names)	The fields a request may group by or measure.
static SeriesAggregator	create()	A new aggregator.
SeriesAggregator	maxBuckets(int value)	The most result cells (bucket and group combinations).
SeriesAggregator	timeField(String value)	The column holding each row's time.
SeriesAggregator	weekStart(DayOfWeek value)	The first day of a week bucket.

Methods inherited from class java.lang.Object

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

Method Details

create

public static SeriesAggregator create()

A new aggregator. Defaults: time field time, weeks start on Monday, at most 10,000 cells, no fields allowed.

Returns:

A new aggregator.

timeField

public SeriesAggregator timeField(String value)

The column holding each row's time.

Parameters:

value - The column name.

Returns:

This object.

weekStart

public SeriesAggregator weekStart(DayOfWeek value)

The first day of a week bucket.

Parameters:

value - The day.

Returns:

This object.

maxBuckets

public SeriesAggregator maxBuckets(int value)

The most result cells (bucket and group combinations).

Parameters:

value - The cap. At least 1.

Returns:

This object.

allowFields

public SeriesAggregator allowFields(String... names)

The fields a request may group by or measure. With none, every such field is rejected.

Parameters:

names - The field names.

Returns:

This object.

aggregate

public SeriesAggregator.Result aggregate(SeriesAggregator.Request req,
 Stream<? extends SeriesSource.Row> rows)

Aggregates the rows in one pass. Rows with a null or out-of-window time are skipped.

Parameters:

req - The request.

rows - The rows, already filtered by the app.

Returns:

The result.

Throws:

SeriesAggregator.RequestException - If the request names a field that is not allowed.