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Imports

In order for one namespace to reference types defined in another namespace, the types must be imported from a versioned namespace. Via imports you can decompose your models into discrete files (and namespaces), version them and build a graph of dependencies between your models.

Single Import​

// imports PostalAddress from version 1.0.0 of the org.accordproject.address namespace
import org.accordproject.address@1.0.0.PostalAddress

Multiple Imports​

To import multiple types from the same namespace, use the {} syntax:

// imports PostalAddress and Country from version 1.0.0 of the org.accordproject.address namespace
import org.accordproject.address@1.0.0.{PostalAddress,Country}

Importing from model published to a public URL​

Import also can use the optional from declaration to import a model file that has been deployed to a URL.

// imports a type from a publicly addressable URL
import org.accordproject.address@1.0.0.PostalAddress from https://models.accordproject.org/address.cto

Imports using a from declaration can be downloaded into the model manager by calling modelManager.updateExternalModels or the concerto get CLI command.

The Model Manager will resolve all imports to ensure that the set of declarations that have been loaded are globally consistent.

Aliasing imported types​

Imported types can also be aliased to local names. Aliasing is only allowed using the {} syntax. Aliased and non-aliased types can be mixed within the same import statement, as demonstrated in the example below


import org.accordproject.address@1.0.0.{PostalAddress as pa, Country}

concept Person{
    o String name
    o pa address optional
    o Country country
}

Import aliasing is enabled by default in Concerto v4. If you are using an older version of Concerto, set environment variable IMPORT_ALIASING='true' or pass importAliasing: true as an option to the ModelManager constructor.

Strict mode​

Concerto v4 always enforces strict mode. Versioned namespaces and explicit versioned imports are required. Unversioned namespaces and wildcard imports are not supported.

Migrating from Concerto 3.x

Concerto 3.x allowed strict: false on the ModelManager constructor, which permitted unversioned namespaces and wildcard imports. This option has been removed in v4. All models must use versioned namespaces (e.g. namespace org.acme@1.0.0) and explicit imports (e.g. import org.acme@1.0.0.{Person}).

The following patterns are no longer valid in Concerto v4:

// ❌ unversioned namespace import — not supported in v4
import org.accordproject.address.PostalAddress
// ❌ wildcard import — not supported in v4
import org.accordproject.address.*