Validation Contraints of $ref (JSON Reference) components are not generated jaxrs-spec

Description

When generating from an openapi 3.0.0 yaml the Validation-Contraints for Java Beans are not generated correctly if $ref ((JSON Reference) is used.

Swagger-codegen version

3.0.0
generatorName: jaxrs-spec

Swagger declaration file content or url

openapi: 3.0.1
paths:
  /accountReferenceIban:
    get:
    responses:
      '200':
      $ref: "#/components/schemas/accountReferenceIban"
components:
  schemas:
    accountReferenceIban:
      type: object
      required:
        - iban
      properties:
        iban:
          $ref: "#/components/schemas/iban"
        currency:
          $ref: "#/components/schemas/currencyCode"
    currencyCode:
      type: string
      pattern: "[A-Z]{3}"
    iban:
      type: string
      pattern: "[A-Z]{2,2}[0-9]{2,2}[a-zA-Z0-9]{1,30}"

Command line used for generation

java -jar swagger-codegen-cli-3.0.0.jar generate -i test.yaml -l jaxrs-spec --api-package=api --model-package=model

Steps to reproduce

Execute command line above. Beside 2 java empty JavaBeans (Iban and CurrrencyCode) the AccountReferenceIban Bean looks like this:

public class AccountReferenceIban  implements Serializable {
  private @Valid String iban = null;  private @Valid String currency = null;

  /**
   **/
  public AccountReferenceIban iban(String iban) {
    this.iban = iban;
    return this;
  }

  
  @ApiModelProperty(required = true, value = "")
  @JsonProperty("iban")
  @NotNull
  public String getIban() {
    return iban;
  }
  public void setIban(String iban) {
    this.iban = iban;
  }

  /**
   **/
  public AccountReferenceIban currency(String currency) {
    this.currency = currency;
    return this;
  }

  
  @ApiModelProperty(value = "")
  @JsonProperty("currency")
  public String getCurrency() {
    return currency;
  }
  public void setCurrency(String currency) {
    this.currency = currency;
  }

Expected Result
iban should have: @Pattern(regexp="[A-Z]{2,2}[0-9]{2,2}[a-zA-Z0-9]{1,30}")
currencyCode should have: @Pattern(regexp="[A-Z]{3}")

if input.yaml looks like the following the output is correct:

openapi: 3.0.1
paths:
  /accountReferenceIban:
    get:
    responses:
      '200':
      $ref: "#/components/schemas/accountReferenceIban"
components:
  schemas:
    accountReferenceIban:
      type: object
      required:
        - iban
      properties:
        iban:
          type: string
          pattern: "[A-Z]{2,2}[0-9]{2,2}[a-zA-Z0-9]{1,30}"
        currency:
          type: string
          pattern: "[A-Z]{3}"

java bean output:

public class AccountReferenceIban  implements Serializable {
  private @Valid String iban = null;  private @Valid String currency = null;

  /**
   **/
  public AccountReferenceIban iban(String iban) {
    this.iban = iban;
    return this;
  }

  
  @ApiModelProperty(required = true, value = "")
  @JsonProperty("iban")
  @NotNull
 @Pattern(regexp="[A-Z]{2,2}[0-9]{2,2}[a-zA-Z0-9]{1,30}")  public String getIban() {
    return iban;
  }
  public void setIban(String iban) {
    this.iban = iban;
  }

  /**
   **/
  public AccountReferenceIban currency(String currency) {
    this.currency = currency;
    return this;
  }

  
  @ApiModelProperty(value = "")
  @JsonProperty("currency")
 @Pattern(regexp="[A-Z]{3}")  public String getCurrency() {
    return currency;
  }
  public void setCurrency(String currency) {
    this.currency = currency;
  }

Reproduce the issue with the supplied test.yaml and the swagger-codegen-cli command using the jaxrs-spec generator. Compare generated AccountReferenceIban output for referenced schemas with the inline-schema output, and verify that the expected @Pattern annotations are present for iban and currency.