io.cdap.wrangler.api.lineage

Class Relation

java.lang.Object

io.cdap.wrangler.api.lineage.Relation

All Implemented Interfaces:

Serializable

@Beta
public final class Relation
extends Object
implements Serializable

The Relation class represents a relation between a list of sources to a list of targets. The relation can have 4 different types and can be many-to-many, many-to-one, one-to-many or one-to-one.

A relation can be of four different types namely:

• DROP type - This type represents relation with a non-existential destination - one-to-none type. This type is used when the column wouldn't be present after the transformation is performed.
• ALL - This type represents a relation with many, one-to-many or many-to-many relation. This type is generally used when the transformation is unclear about what columns would be generated.
• CREATE - This type represents a relation in which a transformation creates a target without having any source.
• GENERATE - This type represents a relation with many, one-to-many or many-to-many relation. This type is generaly used when the transformation is unclear about the input columns
• STANDARD - This type represents all standard relations like many-to-many, many-to-one and one-to-many.

See Also:

Lineage, Many, Mutation, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Relation.Type Specifies the type of relations that can exist between source and target.

Method Summary

Modifier and Type	Method and Description
List<String>	getSources()
List<String>	getTargets()
Relation.Type	getType()
String	id() Deprecated. this id is no longer needed to construct the relation, the wrangler transform will generate id for the relation

Methods inherited from class java.lang.Object

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

Method Detail

id

@Deprecated
public String id()

Deprecated. this id is no longer needed to construct the relation, the wrangler transform will generate id for the relation

Returns:

a String representation of an id for uniquely identifying the relation.

getSources

public List<String> getSources()

Returns:

a List of source columns.

getType

public Relation.Type getType()

Returns:

a Relation.Type this relation represents.

getTargets

public List<String> getTargets()

Returns:

a List of target columns.