com.yahoo.bullet.querying

Class Projection

java.lang.Object

com.yahoo.bullet.querying.Projection

public class Projection
extends Object

Projection consists of a mapping of names to evaluators built from the projection in the Bullet query. If an evaluator fails, only the corresponding field will not be projected, i.e. an evaluator failing does not fail the entire projection. If all evaluators fail, there will be an empty record. Nulls are not projected.

Constructor Summary

Constructors

Constructor and Description
Projection(List<Field> fields) Constructor that creates a Projection from the given fields.

Method Summary

Modifier and Type	Method and Description
com.yahoo.bullet.record.BulletRecord	project(com.yahoo.bullet.record.BulletRecord record) Projects onto a BulletRecord.
com.yahoo.bullet.record.BulletRecord	project(com.yahoo.bullet.record.BulletRecord record, com.yahoo.bullet.record.BulletRecordProvider provider) Projects onto a new BulletRecord.

Methods inherited from class java.lang.Object

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

Constructor Detail

Projection

public Projection(List<Field> fields)

Constructor that creates a Projection from the given fields.

Parameters:

fields - The fields to create a Projection from. Will be non-null.

Method Detail

project

public com.yahoo.bullet.record.BulletRecord project(com.yahoo.bullet.record.BulletRecord record,
                                                    com.yahoo.bullet.record.BulletRecordProvider provider)

Projects onto a new BulletRecord.

Parameters:

record - The record to compute new fields from.

provider - The provider to get the new BulletRecord.

Returns:

A new BulletRecord with fields projected onto it.

project

public com.yahoo.bullet.record.BulletRecord project(com.yahoo.bullet.record.BulletRecord record)

Projects onto a BulletRecord. Projected fields are projected all at once.

Parameters:

record - The record to compute new fields from and to project onto.

Returns:

The original BulletRecord with new fields projected onto it.