Studio schema

In Studio, we can define for each component a schema with associated metadata.

Job run

To access those informations in your component, you’ve to do a few things:

Using the @Structure annotation

  • API: @org.talend.sdk.component.api.configuration.ui.widget.Structure

According the specified field type, you will acess to

  • the column names list with List<String>

  • a subset or all wanted metadata with List<MySchemaMeta> (see below)

@Data
@GridLayout({ @GridLayout.Row({ "dataset" }),
              @GridLayout.Row({ "incomingSchema" }) }) (5)
public class OutputConfig implements Serializable {

    @Option
    @Documentation("My dataset.")
    private Dataset dataset;

    @Option (1)
    @Documentation("Incoming metadata.")
    @Structure(type = Structure.Type.IN) (2) (3)
    private List<SchemaInfo> incomingSchema; (4)
1 @Option: mark class’s attributes as being a configuration entry.
2 @Structure: mark this configuration entry as a schema container.
3 Structure.Type.IN: marks the schema for an incoming flow (Output). Use Structure.Type.OUT for outgoing flow (Input).
4 List<SchemaInfo>: is a custom class for holding metadata.
5 @GridLayout: option should be defined in the UI layout.

Then, we should have a class SchemaInfo as following:

Defining a specific class for holding metadata

If you don’t want just only column names (using List<String>), you’ll have to define a custom class.

@Data
@GridLayout({ @GridLayout.Row({ "label", "key", "talendType", "nullable", "pattern" }) })
@Documentation("Schema definition.")
public class SchemaInfo implements Serializable {

    @Option
    @Documentation("Column name.")
    private String label;

    @Option
    @Documentation("Is it a Key column.")
    private boolean key;

    @Option
    @Documentation("Talend type such as id_String.")
    private String talendType;

    @Option
    @Documentation("Is it a Nullable column.")
    private boolean nullable;

    @Option
    @Documentation("Pattern used for datetime processing.")
    private String pattern = "yyyy-MM-dd HH:mm";
}

Available Studio metadata informations

Field name Type Name in Studio

label

String

Column

originalDbColumnName

String

Db Column

key

Boolean

Key

type

String

DB Type

talendType

String

Type

nullable

Boolean

Nullable

pattern

String

Date Pattern

length

int

Length

precision

int

Precision

defaultValue

String

Default

comment

String

Comment

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